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Öffentlich zugänglich Veröffentlicht von De Gruyter 30. November 2019

The application of essential oils as a next-generation of pesticides: recent developments and future perspectives

Radu Claudiu Fierascu, Ioana Catalina Fierascu, Cristina Elena Dinu-Pirvu, Irina Fierascu und Alina Paunescu

Abstract

The overuse of synthetic pesticide, a consequence of the rush to increase crop production, led to tremendous adverse effects, as they constitute a major pollutant for both soils and water, with a high toxicity towards humans and animals and, at the same time, led to development of pest resistance. In the last period, the researches were directed towards finding new solutions with a lower toxicity, less damaging behaviour towards the environment, and a better specificity of action. In this context, the use of essential oils, a complex and unique mixture of compounds, can be considered for the next-generation pesticides. This review aims to present the main applications of the essential oils as insecticides, herbicides, acaricides, and nematicides, as they emerged from the scientific literature published in the last 5 years (2015 to present). From the identified articles within the time period, only those dealing with essential oils obtained by the authors (not commercially available) were selected to be inserted in the review, characterized using established analytical techniques and employed for the envisaged applications. The review is concluded with a chapter containing the main conclusions of the literature study and the future perspectives, regarding the application of essential oils as next-generation pesticides.

1 Introduction

When referring to the possible threats for the agricultural sector, the pests are accountable for a reduction of the production up to 50% [1]. Over the last decades, this has led to an extensive usage of pesticides, mostly of synthetic origin [Figure 1 presents the global use of pesticide (Figure 1A), as well as details on the global pesticide trade (Figure 1B)].

Figure 1: (A) Pesticide use per cropland (world level); (B) pesticide trade (world level) – data collected from the Food and Agriculture Organization of the United Nations [2], [3].

Figure 1:

(A) Pesticide use per cropland (world level); (B) pesticide trade (world level) – data collected from the Food and Agriculture Organization of the United Nations [2], [3].

Under the general term pesticides, a wide range of compounds with very different actions can be found (such as herbicides, insecticides, nematicides, rodenticides, avicides, algicides, fungicides, bactericides, and others) [4]. Although the introduction of synthetic pesticides in the agricultural practice contributed to an increase in the agricultural output [4], the continuing need of a more performant crop production led to the overuse of these types of compounds in such extent that they become a major pollutant for both soils and water, with a high toxicity towards humans and animals [5], [6]. The worldwide usage of synthetic pesticides has presented the research community with the rise of several issues, such as the continuous development of pesticide resistance. This can be attributed to a misuse of the pesticides, meaning that the shortcoming of specific substances for certain pests will increase their adaptability and make the resistance traits to be passed on to the next pest generations [7]. One of the biggest concerns regarding the effects of synthetic pesticides is the influence upon human and animal health. Several studies have linked a higher occurrence of cancer within the farmers’ communities that have been exposed to pesticides. Ochoa-Acuña and Carbajo have pointed out the connection between birth defects, such as prematurity and congenital abnormalities, and the extensive use of pesticides [8]. Associated with the increased use of synthetic pesticides, the economic losses induced by their use also increased. For example, in the United States alone, the costs related to the pesticide use were estimated at greater than US $10 billion per year (2005), including the costs related to public health, development of pesticide resistance in pests, crop and bird losses, or groundwater contamination [9].

In the last years, in order to inhibit some of the negative effects of the existent pesticides, a new approach had risen to the attention of the research community, that of the essential oil–based pesticides [10], [11]. In previous studies, it has been proven that essential oils used as pesticides can be more advantageous, as their toxicity is much lower; they present a less damaging behaviour towards the environment and have a better specificity of action [12], [13], [14].

Essential oils (EOs), due to their nature (as plant secondary metabolites), represents a safer alternative in many applications, such as food preservation, biomedicine, cosmetics, or agriculture [15]. From the chemical point of view, EOs represent a complex and unique mixture of compounds, specific for each plant and extraction procedure, including, but not limited to alkaloids, flavonoids, isoflavones, monoterpenes, phenolic acids, carotenoids, and aldehydes [16], strongly lipophilic and volatile and nearly insoluble in water.

Although the costs for obtaining EOs for such applications are increased (when compared with synthetic pesticides), they represent a viable alternative (especially for application in organic agriculture, where the focus is shifted from costs and absolute efficacy towards human and animal safety) [17]. Their application can solve the problem of pesticide-resistant pests, as well as avoid the health issues related to pesticide accumulation [18]. Moreover, the world market for EOs is expected to reach 403.06 kilotons by 2025 [19]; the large-scale and worldwide production is expected to have a positive effect on the price of EOs, whereas their volatility makes EOs environmentally nonpersistent [17], thus eliminating several of the side effects of synthetic pesticides. The increasing interest in the application of EO formulations as pesticides can be observed by evaluating the number of scientific articles published on this topic over the years, in Web of Science indexed journals (Figure 2). Web of Science database was selected in order to consider the review-only research articles published in ISI-indexed journal. From the larger class of pesticides, the application of EOs as bactericidal, fungicidal, and virucidal agents was not considered. The primary selection in this review was made by using the following keywords: “essential oil” and selection “article” (52,804 results). Within those results, particular searches were made using “insecticide/insecticidal/insect repellent” (2025 results), “herbicide/herbicidal” (190 results), “acaricide/acaricidal” (140 results), and “nematicide/nematicidal” (51 results). From this preliminary selection, articles published in the last 5 years (2015–2019) were considered for the present review (1224 articles). The final selection of the articles was made after careful evaluation: “false-positive” articles were removed (articles containing the keywords but not truly presenting the application); only those articles dealing with EOs obtained by the authors in the laboratory (not commercialized EOs) and characterized using established analytical techniques (such as gas chromatography-mass spectrometry) were included in the present review (82 articles).

Figure 2: Evolution of the scientific articles published on the topic EO application as pesticides (bactericidal, fungicidal, and virucidal applications excluded). Highlighted area represents the time frame considered for the present review.

Figure 2:

Evolution of the scientific articles published on the topic EO application as pesticides (bactericidal, fungicidal, and virucidal applications excluded). Highlighted area represents the time frame considered for the present review.

The review covers the extraction procedures followed by the author, main components identified, and the targeted organisms. In addition, exhaustive tables, containing the main data regarding the application of EOs, are provided, for quick reference. The review ends with a chapter containing the main conclusions of the literature study and the future perspectives, regarding the application of EOs as “green” pesticides.

2 Application of EOs as insecticides and insect repellent

One of the most important categories of pesticides is represented by insecticides, as they can minimize the damages produced by pests and can lead to an improvement of the productivity of the horticultural sector. At the same time, insects can lead to a series of serious health issues, such as the yellow fever or those developed by dengue and chikungunya viruses [20]. The difference between insecticide and insect repellent is represented by the desired application (usually insect repellents are designed for human protection, whereas the insecticides are designed for agricultural applications) and by the interaction pathway between the pesticide and the targeted pest: insecticides act by direct contact, whereas for a compound to be classified as an insect repellent, it should create within 4 cm of the skin an atmosphere that would prevent the contact insect/skin [20]. The wide application of insecticides and insect repellents led to the proposal of “green” alternatives, based on natural products. As the two applications are often evaluated together, we have chosen to present the recent developments in those areas chronologically, in a single chapter.

Akkari et al. [21] used Ruta chalepensis (Rutaceae) EO obtained by vapour dragging and water distillation and evaluated it in terms of larvicidal effect against larvae of Orgyia trigotephras (a phytophagous insect). The authors obtained a mean time of mortality of 1.40 min (flower oil) and 1.27 min (leaf oil) for the third instar larvae, respectively, 42.53 and 20.68 min against the fourth instar larvae (at 0.5% EO in ethanol vol/vol), superior to a commercial insecticide (deltamethrin) used as positive control (time of mortality of 31.1 min against the third instar larvae, respectively, 596.35 min, against the fourth instar larvae, at 0.015% concentration).

Jalaei et al. [22] used the EO of Dracocephalum kotschyi Boiss. obtained by water distillation (with high monoterpene content) as an efficient insecticide against Myzus persicae Sulz. (an aphid causing major losses to the peach cultures), with LC50 (50% mortality) after 72 h of 0.27 μL/L and LC90 of 2.35 μL/L after 72 h (fumigant), comparable to the commercial insecticide Actara used as positive control. Li et al. [23] applied EO obtained by water distillation from the aerial parts of Clinopodium chinense (Benth.) Kuntze against the booklice (Liposcelis bostrychophila), with a 50% lethal concentration (LC50) of 215.25 μg/cm2 (contact), respectively, 423.39 μg/L air (fumigant), whereas Sumitha and Thoppi [24] used Ocimum gratissimum L. leaf EO as insecticidal agent against Aedes albopictus Skuse, with LC50 value of 26.10 mg/L and LC90 of 82.83 mg/L, at 24 h.

Wang et al. [25] used Dahlia pinnata Cav. EO against Sitophilus zeamais and Sitophilus oryzae (pests of stored cereals), with LC50 value of 308.11 and 163.55 mg/cm2 for the insecticidal effect (contact), respectively, and strong insect repellent properties at 13 nL/cm2. A similar approach regarding the evaluation of EOs as insecticide and insect repellent can be encountered in the studies published in the same year (2015), by Martínez-Evaristo et al. [26], Aguiar et al. [27], de Lira et al. [28], Guo et al. [29], Haider et al. [30], Wu et al. [31], Yang et al. [32], You et al. [33], and Zhang et al. [34] (details provided in Table 1). Among these articles, the work of Haider et al. [30] presents the variation in composition and effect of the EO of Tanacetum nubigenum Wallich. ex DC harvested from three different sites, at different elevations. Considering their results, it can be stated that the potential application of EOs is strongly correlated with their composition, which in turn varies with several factors, including the value of the cultivar, the harvesting time, and the environmental factors.

Table 1:

Origin and major composition of the essential oils presented in the review with insecticidal and insect repellent effects.

EffectPlant materialMajor composition (%)Targeted pestEffect quantificationRef.
IRuta chalepensis leaves2-Undecanone (85.94), 2-decanone (5.63), 2-dodecanone (1.21), by GC-MSOrgyia trigotephras larvaeMTM=1.27 min for third instar larvae, 20.68 min for fourth instar larvae[21]
IRuta chalepensis flowers2-Undecanone (89.89), 2-decanone (4.23), 2-dodecanone (1.22), by GC-MSOrgyia trigotephras larvaeMTM=1.40 min for third instar larvae, 42.53 min for fourth instar larvae[21]
IAerial flowering parts of Dracocephalum kotschyiLimonene-10-al (73.75), limonene (19.96), menth-1-en-9-ol (1.14), by GC-MSMyzus persicaeLC50=0.27 μL/L air, LC90=2.35 μL/L air after 72 h (fumigant)[22]
IAerial parts of Clinopodium chinenseSpathulenol (18.54), piperitone (18.9), caryophyllene (12.04), by GC-MSLiposcelis bostrychophilaLC50=215.25 μg/cm2 (contact), LC50=423.39 μg/L air (fumigant)[23]
IOcimum gratissimum L. leaves3-Allyl-6-methoxyphenol (19.30), 4-(5-ethenyl-1-azabicyclo (2, 2, 2) octan-2) (16.82), 1-(2, 5-dimethoxyphenyl)-propanol (12.23), by GC-MSAedes albopictusLC50=26.10 mg/L air, LC90=82.83 mg/L air, at 24 h[24]
I, IRDahlia pinnata4-Terpineol (25.71), methallyl cyanide (13.96), d-limonene (10.53), by GC-MSSitophilus zeamais, Sitophilus oryzaeLC50=308.11/163.55 mg/cm2

(contact); strong insect repellent properties at 13 nL/cm2
[25]
I, IRLippia palmeri S. WatsonThymol (58.9), p-cymene (21.8), carvacrol (5.2) by GC-MSSitophilus zeamais, Prostephanus truncatusLC50=441.45 μL/L air/320.52 μL/L air (fumigant)

LC90=1177.2 μL/L air/1558.9 μL/L air (fumigant)

RI=0.45/0.5 at 1000 μL/L air after 72 h
[26]
I, IRSiparuna guianensis Aubl. leavesβ-Myrcene (79.71), 2-undecanone (14.58), bicyclo-germacrene (1.21%), by GC-MSAedes aegypti, Culex quinquefasciatusLC50=1.76 (A. aegypti), 1.36 mg/L air (C. q.), fourth instar larvae;

RD50=0.438/0.662 μg/cm2
[27]
I, IRSiparuna guianensis Aubl. stemβ-Myrcene (26.91), δ-elemene (20.92), germacrene D (9.4%), by GC-MSAedes aegypti, Culex quinquefasciatusLC50=0.98 (A. aegypti), 0.89 mg/L air (C. q.), fourth instar larvae;

RD50=0.438/0.662 μg/cm2
[27]
I, IRSiparuna guianensis Aubl. fruits2-Tridecanone (38.75), 2-undecanone (26.5) and β-myrcene (16.42), by GC-MSAedes aegypti, Culex quinquefasciatusLC50=2.46 (A. aegypti), 2.45 mg/L air (C. q.), fourth instar larvae;

RD50=0.438/0.662 μg/cm2
[27]
I, IRAlpinia purpurata inflorescencesβ-Pinene (35.76), α-pinene (20.57), trans-caryophyllene (13.23), by GC-MSSitophilus zeamais MotschLC50=41.4 μL/L air (fumigant)

No repellent effect
[28]
I, IREtlingera yunnanensis rhizomesEstragole (65.2), β-caryophyllene (6.4), 1,8-cineole (6.4), by GC-MSTribolium castaneum (Herbst) and Liposcelis bostrychophila (Badonnel)LC50=23.33 μg/adult/47.38 μg/cm2 (contact)

PR=84%, 2 h, 15.73 nL/cm2/82%, 2 h, 12.63 nL/cm2
[29]
I, IRTanacetum nubigenum Wallich. ex DC from 4000 mSelin-11-en-4-α-ol (10.3), methyl acetopyronone (9.5), 2,6,8-trimethyl-4-nonanone (8.8), by GC-MSTribolium castaneum (Herbst)LC50=33.25 μL/L air, at 48 h;

RE=1.3 adults, 1 h treatment, 20 μL/plate EO
[30]
I, IRTanacetum nubigenum Wallich. ex DC from 3200 mBorneol (19.8), p-menthene-1-ol (11.7), 1,8-cineole (10.9), by GC-MSTribolium castaneum (Herbst)LC50=36.88 μL/L air, at 48 h;

RE=2.7 adults, 1 h treatment, 20 μL/plate EO
[30]
I, IRTanacetum nubigenum Wallich. ex DC from 3500 mBornyl acetate (38.1), borneol (9.5), 1,8-cineole (7.3), by GC-MSTribolium castaneum (Herbst)LC50=35.28 μL/L air, at 48 h;

RE=2.2 adults, 1 h treatment, 20 μL/plate EO
[30]
I, IRLiriope muscari aerial partsMethyl eugenol (42.15), safrole (17.15), myristicin (14.18), by GC-MSTribolium castaneum, Lasioderma serricorne, Liposcelis bostrychophilaLC50=13.36/11.28 μg/adult, respectively, 21.37 μg/cm2

PR=92%, 2 h, 15.73 nL/cm2 (T.c.), 86%, 2 h, 78.63 nL/cm2 (L.s.), 100% 2 h, 6.32 nL/cm2 (L.b.)
[31]
I, IRDictamnus dasycarpus rootsSyn-7-hydroxy-7-anisylnorbornene (49.9), 1,3,4,5,6,7-hexahydro-2H-inden-2-one (11.6), 5,6-diethenyl-1-methylcyclohexene (7.38), by GC-MS andLasioderma serricorne, Liposcelis bostrychophilaLC50=12.4 mg/adult/27.2 mg/cm2

PR=90%, 4 h, 39.32 nL/cm2/98%, 4 h, 6.32 nL/cm2
[32]
I, IRArtemisia mongolica aerial partsEucalyptol (39.88), (S)-cis-verbenol (14.93), 4-terpineol (7.20), by GC-MSLasioderma serricorneLC50=22.32 μg/adult;

LC50=6.08 mg/L air

RE=~76%, 39.32 ng/cm2, 2, 4 h
[33]
I, IRMentha haplocalyx aerial partsMenthol (59.71), menthyl acetate (7.83), limonene (6.98), by GC-MS andLasioderma serricorneLC50=16.5 μg/adult

RE=>95%, 2 h, 39.32 ng/cm2
[34]
IPinus kesiya Royle ex. Gordon needlesβ-Pinene (38.9), α-pinene (21.8), myrcene (11.6), by GC-MSAnopheles stephensi, Aedes aegypti, Culex quinquefasciatusLC50=52/57/62 mg/L air; LC90=101/110/115 mg/L air (fumigant)[35]
ITeucrium quadrifarium aerial partsGermacrene D (8.8), linalool (8.2), camphene (7.8), by GC-MSLiposcelis bostrychophilaLC50=95.1 μg/cm2 (contact), 222.0 μg/L (fumigant)[36]
ICyperus rotundus rhizomesα-Cyperone (29.38), cyperene (13.97), caryophyllene oxide (6.71), by GC-MSLiposcelis bostrychophilaLC50=102.11 μg/cm2 (contact)[37]
IElsholtzia ciliate aerial partsDehydroelsholtzia ketone (26.5), (R)-carvone (16.6), elsholtzia ketone (14.6), by GC-MSLiposcelis bostrychophilaLC50=145.5 μg/cm2 (contact), 475.2 μg/L (fumigant)[38]
IMentha pulegium L. leavesPulegone (70.66), neo-menthol (11.21), menthone (2.63), by GC-MSSitophilus granarius (L.)LC50=9.11 mL/L (contact), 100% mortality at inhalation and ingestion after 24 h, using 5/10 mL EO/L acetone[39]
IPistacia atlantica subsp. kurdica gumα-Pinene (81.6), terpinolene (4.09), β-pinene (3.6), by GC-MSTribolium castaneum (Herbst)LC50=29 μL/L air; LC90=57 μL/L air (fumigant)[40]
IPistacia atlantica subsp. kurdica fruitα-Pinene (47.7), β-myrcene (16.1), d-limonene (8.75), by GC-MSTribolium castaneum (Herbst)LC50=39 μL/L air; LC90=66 μL/L air (fumigant)[40]
IPistacia atlantica subsp. kurdica leavesSpathulenol (24.1), α-pinene (19.2) and δ-elemene (7.05), by GC-MSTribolium castaneum (Herbst)LC50=64 μL/L air; LC90=87 μL/L air (fumigant)[40]
I, IRCinnamomum camphora L. Presl leavesCamphor (18.48), eucalyptol (16.46), linalool (11.58), by GC×GC-TOFMSAphis gossypii GloverLC50=245.79 mg/L at 48 h (contact);

PR=83.83 at 24 h, 20 mL/L EO
[41]
I, IRCinnamomum camphora L. Presl twigsEucalyptol (17.21), camphor (13.17), 3,7-dimethyl-1,3,7-octatriene (11.47), by GC×GC-TOFMSAphis gossypii GloverLC50=274.99 mg/L at 48 h (contact);

PR=72.13 at 24 h, 20 mL/L EO
[41]
I, IRCinnamomum camphora L. Presl seedsEucalyptol (20.90), methyleugenol (19.98), linalool (14.66), by GC×GC-TOFMSAphis gossypii GloverLC50=146.78 mg/L at 48 h (contact);

PR=89.86 at 24 h, 20 mL/L EO
[41]
I, IRPluchea carolinensis (Jacq.) G. Don flowers5-Angeloyloxycarvotagetone (18.1), selin-11-en-4α-ol (17.7), 2,5-dimethoxycymene (8.9), linalool (14.66), by GC-MS, NMR, HRMSAedes aegyptiPTA=1.6% at 1% EO; PIA=66.2% at 0.1% EO; PR=36.6% at 1% EO[42]
I, IRCryptocarya alba [Molina] Looser foliage(E)-β-bergamotene (15.6), viridiflorol (8.5), germacrene-D (7.65), by GC-MSSitophilus zeamais MotschulskyLC50=14.6 mL/kg grain;

RI=0.28 at 2.5 mL EO/kg grain
[43]
I, IRJuniperus formosana leavesα-Pinene (21.66), 4-terpineol (11.25), limonene (11.00), by GC-MSTribolium castaneum, Liposcelis bostrychophilaLC50=29.14 μg/adult/81.50 μg/cm2 (contact);

PR=>90% at 2 h, 78.63 nL/cm2 (T.c.), 76% at 4 h, 63.17 nL/cm2 (L.b.)
[44]
I, IRRhododendron thymifolium leavesGermacrone (20.83), γ-elemene (11.10), selina-3,7(11)-diene (6.18), by GC-MSLiposcelis bostrychophila, Tribolium castaneumLC50=19.63 μg/cm2/29.82 μg/cm2 (contact);

PR >90% at 4 h, at 15.73 nL/cm2 (T.c.), 12.64 nL/cm2 (L.b.)
[45]
I, IRLaureliopsis philippiana (Looser) Schodde leavesMethyleugenol (61.38), safrole (17.04), β-terpinene (4.49), by GC-MSSitophilus oryzae, Sitophilus zeamais, Sitophilus granariusMR=94.8/60.2/67.1 at 4% EO (contact);

MR=100% at 200 μL EO/L air (fumigant);

RI=0.4/0.2/0.5 at 4% EO
[46]
I, IREucalyptus floribundi leaves1,8-Cineole (58), α-pinene (26.2), trans-pinocarveol (4.05), by GC-MSRhyzopertha dominica, Oryzaephilus surinamensisLC50=34.39/43.54 μg/L air (fumigation);

RI=0.21/0.11 at 280/140 μL/L air
[47]
IBidens frondosa L. aerial partsCaryophyllene oxide (20.50), borneol (17.66), 4-terpineol (17.26), by GC-MSLiposcelis bostrychophilaLC50=507.35 μg/L (fumigation);

LC50=210.73 μg/cm2 (contact)
[48]
ILeaves of Psidium guajava L. cultivars(E)-Caryophyllene (26.6-7.6), caryophyllene oxide (3.2-16.6), β-bisabolol (2.4-19.5), others, by GC-MSAedes aegypti L.LC50=39.48-64.25 mg/L[49]
ICitrus sinensis peelsLimonene (92.14), β-myrcene (2.7), 1,8-cineole (0.33), by GC-MSTribolium confusum, Callosobruchus maculatus, Sitophilus oryzaeLC50=14.45/10/29.51 μL/L, at 72 h (fumigant)[50]
I, IRZingiber zerumbet (L.) Smith rhizomesZerumbone (40.2), α-caryophyllene (8.6), humulene epoxide II (7.3), by GC-MSLasioderma serricorneLC50=48.3 μg/adult (contact);

PR=72%, at 2 h, 78.63 nL/cm2
[51]
I, IRCymbopogon nardus L. leavesGeraniol (19.34), methyl eugenol (8.8), (E)-methyl isoeugenol (8.19), by GC-MSBemisia tabaciLC50=1.028 μL/L, at 24 h (fumigant);

RI=0.29% at 6 h, 0.5% EO
[52]
I, IREupatorium buniifolium Hook et Arn. aerial parts(−)-α-Pinene (38.02-75.77), others, depending on year and location, by GC-MSTriatoma infestansMortality 92-100% for 50-150 μL/L (fumigant);

Repellent at 25 and 50% EO
[53]
ILantana camaraSabinene (32.1), 1.8 cineole (20.9), (E)-caryophyllene (13), by GC-MSAnopheles gambiae (Meigen)LC50=0.24/1.04/0.85/1.22%;

LC90=0.89/1.54/1.38/2.00% (contact)
[54]
IHyptis spicigeraα-Pinene (24.5), (E)-caryophyllene (23.6), β-pinene (10.3), by GC-MSAnopheles gambiae (Meigen)LC50=1.04%;

LC90=1.54% (contact)
[54]
IHyptis suaveolensSabinene (26.9), 1.8 cineole (26.4), (E)-caryophyllene (11.1), by GC-MSAnopheles gambiae (Meigen)LC50=0.85%;

LC90=1.38% (contact)
[54]
IOcimum canum1.8 Cineole (44.6), camphor (15.9), α-pinene (7.1), by GC-MSAnopheles gambiae (Meigen)LC50=1.22%;

LC90=2.00% (contact)
[54]
IGeranium macrorrhizum L. – wild aerial partsβ-Elemenone (30.53), thymol (18.52), germacrone (15.54), by GC-MSSpodoptera littoralis, Myzus persicae, Rhopalosiphum padiFI=55.5 (S.l.); SI=31.1 (M.p.), 69.9 (R.p.), at 10 mg/mL[55]
IGeranium macrorrhizum L.–commercial aerial partsLinalool (26.45), linalyl acetate (25.11), geranyl acetate (7.56), by GC-MSSpodoptera littoralis, Myzus persicae, Rhopalosiphum padiFI=87.8 (S.l.); SI=55.1 (M.p.), 77.8 (R.p.), at 10 mg/mL[55]
I, IREvodia lenticellata HuangCaryophyllene oxide (28.5), β-caryophyllene (23.1), β-elemene (14.5, by GC-MSTribolium castaneum, Lasioderma serricorne, Liposcelis bostrychophilaLD50=41.5 μg/adult (L.s.), 98 μg/cm2 (against L.b.) (contact);

PR=>80% against T.c., L.s., at 78.63nL/cm2 and 2 h
[56]
I, IREvodia rutaecarpa (Juss.) Benth. leavesα-Pinene (39.4), β-elemene (13.5), α-ocimene (7.6), by GC-MSTribolium castaneum, Lasioderma serricorne, Liposcelis bostrychophilaLD50=46.2 μg/adult (L.s.) (contact);

PR=>80% E.l. against T.c., L.s.; >80% against all insects, at 78.63nL/cm2 and 2 h
[56]
I, IRAmomum villosum Lour. fruitsBornyl acetate (51.6), camphor (19.8), camphene (8.9), by GC-MSTribolium castaneum, Lasioderma serricorneLD50=32.4/20.4 μg/adult (contact);

LC50=6.2 mg/L air (fumigant);

PR=>70%, 2 h, 78.63 nL/cm2
[57]
IRosmarinus officinalis–Middle Atlas site1, 8-Cineole (46.23), camphor (17.29), β-pinene (5.62), by GC-MSBruchus rufimanusLC50=1.19 μL/L air (males, after 7 days)/2.08 μL/L air (females, after 7 days)[58]
IRosmarinus officinalis–Loukkos siteCamphor (21.33), 1, 8-cineole (17), β-pinene (8.58), by GC-MSBruchus rufimanusLC50=11.57 μL/L air (males, after 6 days)/5.38 μL/L air (females, after 11 days)[58]
IBoenninghausenia albiflora1,8-Cineol (18.5), germacrene-D (17.75), bicyclo germacrene (14.60)/, by GC-MSSpilarctia obliquaMR=66.67 at 2.5 μL (larval stage); 26.33 at 2.5 μL (pupal stage)[59]
ITeucrium quadrifariumE-caryophyllene (25.0), α-cubebene (20.1) and copane 4-α-ol (10.0), by GC-MSSpilarctia obliquaMR=70.83 at 2.5 μL (larval stage); 20 at 2.5 μL (pupal stage)[59]
IPimpinella anisum(E)-anethole (96.7), methyl chavicol (1.6), γ-himachalene (0.5), by GC-EIMSCulex quinquefasciatusLC50=2.39 mL microemulsion (1.5% EO)/L on 3rd instar larvae

LM=80.7 after 144 h; AE=9.3% at 1.7 mL/L emulsion
[60]
ITrachyspermum ammi schizocarpsThymol (62.6), p-cymene (18.7), γ-terpinene (15.8), by GC-EIMSCulex quinquefasciatusLC50=1.57 mL microemulsion (1.5% EO)/L on 3rd instar larvae

LM=51.7 after 144 h; AE=45.2% at 1.3 mL/L emulsion
[60]
ICrithmum maritimum flowering aerial partsγ-Terpinene (33.0), thymol methyl ether (22.0), dillapiole (17.5), by GC-EIMSCulex quinquefasciatusLC50=2.23 mL microemulsion (1.5% EO)/L on 3rd instar larvae

LM=56.7 after 144 h; AE=27.7% at 1.8 mL/L emulsion
[60]
I, IRSeverinia monophylla leaves–site 1β-Caryophyllene (14.8), bicyclogermacrene (8.9), germacrene D (7), by GC-MSAedes aegypti, Aedes albopictus/Triatoma rubrofasciataLC50=7.1 μg/mL at 48 h;

PR=80% after 48 h
[61]
I, IRSeverinia monophylla leaves–site 2β-Caryophyllene (10.9), bicyclogermacrene (9.2), germacrene D (7.6), by GC-MSAedes aegypti, Aedes albopictus/Triatoma rubrofasciataLC50=36 μg/mL at 48 h;

PR=80% after 48 h
[61]
IPlectranthus amboinicusCarvacrol (61.53), β-caryophyllene (12.79), p-cymene (9.42), by GC-MSAedes aegypti, Aedes albopictus, Culex quinquefasciatusLC50=42.9/51.62/22.88 mg/L air[62]
IMentha requieniiPulegone (60.33), isopulegone (17.32), isomenthone (2.55), by GC-MSAedes aegypti, Aedes albopictus, Culex quinquefasciatusLC50=53.92/56.13/49.65 mg/L air[62]
IVitex rotundifoliaα-Pinene (23.64), 1.8-cineole (23.86), sabinene (8.94), by GC-MSAedes aegypti, Aedes albopictus, Culex quinquefasciatusLC50=53.53/68.06/47.46 mg/L air[62]
ICrossostephium chinenseSantolina triene (50.90), 1.8-cineole (17.89), thuj-3-en-10-al (5.68), by GC-MSAedes aegypti, Aedes albopictus, Culex quinquefasciatusLC50=72.20/72.77/65.74 mg/L air[62]
IOcimum campechianumEugenol (18.6), β-caryophyllene (17), 1,8-cineole (11.4), by GC-MSAedes aegyptiLC50=69.3 mg/L air[63]
IOcotea quixos1,8-Cineole (39.2), sabinene (6.5), α-pinene (6.3), by GC-MSAedes aegyptiLC50=75.5 mg/L air[63]
IPiper aduncumDillapiole (48.2), trans-ocimene (7.5), β-caryophyllene (17.0), by GC-MSAedes aegyptiLC50=25.7 mg/L air[63]
IMyrciaria floribunda leaves1,8-Cineole (10.4), β-selinene (8.4), α-selinene (7.4), by GC-MSRhodnius prolixusLD50=742.49-10.51 (1st–30th days after treatment) μg/insect[64]
IKadsura coccinea (Lem.) A. C. Smβ-Caryophyllene (24.73), caryophyllene oxide (5.91), α-humulene (3.48), by GC-MSCimex lectularius L.MR=61.9%, Bayonne strain, 1st day of treatment, 90.5% Ft. Dix strain, 5th day of treatment, at 100 μg/bug[65]
IAtriplex cana Ledeb. aerial partsDibutyl phthalate (21.79), eucalyptol (20.14), myrtenyl acetate (15.56), by GC-MSAphis pomi DeGeerMR=84.5% at 12 h, 100% at 48 h, with 5 μL/Petri dish[66]
I, IROriganum vulgareCarvacrol (78.2), p-cymene (4.4), γ-terpinene (3.2), by GC-MSIps typographusLC50=0.006 μL/cm2 at 96 h RI=70.1% at 0.286 μL/cm2, 2 h[67]
I, IRThymus vulgarisThymol (50.4), limonene (33.6), fenchyl acetate (4.6), by GC-MSIps typographusLC50=0.11 μL/cm2 at 96 h

RI=83.7% at 0.286 μL/cm2, 4 h
[67]
I, IRHyssopus officinaliscis-Pinocamphone (44.4), isopinocamphone (25.2), β-pinene (12.3), by GC-MSIps typographusRI=91.3%, at 0.286 μL/cm2, 2 h[67]
I, IRMentha×piperitaMenthol (49.3), menthone (22.4), limonene (9.4), by GC-MSIps typographusNo repellent activity[67]
I, IRPimpinella anisumAnethole (88.6), estragole (4.4), linalool (1.4), by GC-MSIps typographusLC50=0.053 μL/cm2 at 96 h, RI=79.5%, at 0.077 μL/cm2, 2 h[67]
I, IRFoeniculum vulgareAnethole (65.5), fenchone (20.2) and estragole (5.0), by GC-MSIps typographusRI=93.6% at 0.077 μL/cm2, 2 h[67]
I, IRAgave Americana leavesHexacosane (23.38), heptacosane (21.48), pentacosane (16.66), by GC-MSSitophilus oryzae (L.)LC50=10.55 μg/insect (topical), LC50=8.99 μg/cm2 (treated filter paper);

RC50=0.055 μg/cm2
[68]
I, IRValeriana officinalis rootsBornyl acetate (48.2), camphene (13.8), β-pinene (2.8), by GC-MSLiposcelis bostrychophila, Tribolium castaneumLC50=2.8 mg/L air

(fumigant) (L.b.);

LD50=50.9/10 μg/cm2

PR=>95% at 2 h at 12.63/15.73 nL/cm2
[69]
I, IRHaplophyllum dauricum (L.) G. Don October fruitsβ-Pinene (42.37), limonene (15.77), β-thujene (13.15), by GC-MSTribolium castaneum, Lasioderma serricorneLC50=14.55/25.89 mg/L air (fumigant); LC50=>50/31.24 μg/adult (contact)

RE=92% at 2 h, 78.63 nL/cm2/72% at 2 h, 3.15 nL/cm2
[70]
I, IRHaplophyllum dauricum (L.) G. Don October stems and leavesβ-Pinene (29.19), β-thujene (17.77), α-pinene (17.61), by GC-MSTribolium castaneum, Lasioderma serricorneLC50=14.91/17.17 mg/L air (fumigant); LC50=20.21/25.46 μg/adult (contact)

RE=92% at 2 h, 78.63 nL/cm2/34% at 2 h, 3.15 nL/cm2
[70]
I, IRHaplophyllum dauricum (L.) G. Don November fruitsβ-Pinene (40.86), α-pinene (16.47), β-phellandrene (14.49), by GC-MSTribolium castaneum, Lasioderma serricorneLC50=54.41/19.54 mg/L air (fumigant); LC50=39.58/26.18 μg/adult (contact)

RE=100% at 2 h, 15.83 nL/cm2/86% at 4 h, 3.15 nL/cm2
[70]
I, IRHaplophyllum dauricum (L.) G. November leavesβ-Pinene (30.57), 3-carene (26.84), β-phellandrene (21.34), by GC-MSTribolium castaneum, Lasioderma serricorneLC50=12.09/74.08 mg/L air (fumigant); LC50=>50/28.04 μg/adult (contact)

RE=100% at 4 h, 78.63 nL/cm2/76% at 2 h, 78.63 nL/cm2
[70]
I, IRHaplophyllum dauricum (L.) G. Don November stemsα-Bisabolol oxide B (12.04), bornyl acetate (7.12), limonene (6.24), by GC-MSTribolium castaneum, Lasioderma serricorneLC50=22.75/19.08 mg/L air (fumigant); LC50=20.21/25.46 μg/adult (contact)

RE=100% at 2 h, 15.83 nL/cm2/100% at 4 h, 78.63 nL/cm2
[70]

  1. All EOs were obtained by water distillation/steam distillation. Entries are ordered chronologically. FI, Feeding inhibition; GC-MS, gas chromatography-mass spectrometry; I, insecticidal; IR, insect repellent; LC50, lethal concentration that kills 50% of the exposed organisms; LC90, lethal concentration that kills 90% of the exposed organisms; LM, larval mortality; MR, mortality rate; PIA, percentage of irritating activity; PR, percentage repellency; PTA, percentage of toxic activity; RC50, concentration that repels 50% of organisms; RD50, (repellency dose) dose that repels 50% of insects; RE, repellent efficiency; RI, repellency index; SI, setting inhibition.

A very interesting study was published in 2016 by Govindarajan et al. [35] regarding the application of EO extracted from an Asian pine species (Pinus kesiya Royle ex. Gordon) as a potent insecticide against three species of mosquitos (malaria vector Anopheles stephensi, dengue vector Aedes aegypti, lymphatic filariasis vector Culex quinquefasciatus). Their results (mortality between 96% and 100% for all species at a 125 mg/L concentration EO) suggested the potential of EOs for controlling the larvae of dangerous mosquito species. The insecticidal effect of different EOs was tested in the same year by several groups against the booklice (L. bostrychophila) [36], [37], [38] and against stored products pests (Sitophilus granarius, Tribolium castaneum) [39], [40], with good results (more details provided in Table 1).

Jiang et al. [41] evaluated the insecticidal and insect repellent potential of EOs obtained from leaves, twigs, and seeds of Cinnamomum camphora L. Presl against the cotton aphid (Aphis gossypii Glover), the best results being obtained for the seeds EO (LC50=146.78 mg/L after 48 h, respectively, 89.86% repellency at 20 mL/L EO after 24 h), whereas Kerdudo et al. [42] evaluated the insecticidal and insect repellent potential of Pluchea carolinensis (Jacq.) G. Don flowers EO against the yellow fever mosquito (A. aegypti), obtaining superior results for the repellent and irritating activities (36.6%, respectively, 66.2%, at 1% EO in ethanol vol/vol), compared to the commercial standard DEET (N,N-diethyl-3-methylbenzamide) (20.7%, respectively, 21%). Similar studies, incorporating the evaluation of the insecticidal and insect repellent activity, were performed in the same year by Pinto et al. [43], Guo et al. [44], Liang et al. [45], Norambuena et al. [46], and Aref et al. [47] against some common pests (S. zeamais Motschulsky, T. castaneum, L. bostrychophila, S. oryzae, S. granarius, Rhyzopertha dominica, Oryzaephilus surinamensis).

In their works published in 2017, Li et al. [48], Mendes et al. [49], and Oboh et al. [50] studied the insecticidal effect of EOs obtained from Bidens frondosa L. aerial parts, different Psidium guajava L. cultivars, respectively, orange peels, against different pests (L. bostrychophila, A. aegypti, respectively, Tribolium confusum, Callosobruchus maculatus, and S. oryzae). Other authors used both assays discussed in this chapter for the evaluation of EOs. Wu et al. [51] presented the potent contact and repellent activity effect of EOs obtained from Zingiber zerumbet (L.) Smith rhizomes on the cigarette beetles (Lasioderma serricorne), whereas Saad et al. [52] used citronella EO against the sweet potato whitefly, contributing to the list of pests that could be controlled by the use of EOs.

Application of EO as insecticides against some severe illnesses vectors was described in 2018 by Guerreiro et al. [53], who used Eupatorium buniifolium against the Chagas disease vector Triatoma infestans (Klug), and Wangrawa et al. [54], who applied several EOs against the malaria vector Anopheles gambiae (results detailed in Table 1), assigning the biological potential of EOs to the presence of oxygenated monoterpenes, sesquiterpenes hydrocarbons, and hydrocarbon monoterpenes. Several other studies describe the application of various EOs for the control of insects causing severe economic losses [55], [56], [57], [58], [59]. Among those studies, it is worth to mention the studies of Navarro-Rocha et al. [55], who evaluated two populations of Geranium macrorrhizum L. The wild variety (cultivated in Hungary) showed superior properties (in terms of feeding inhibition and setting inhibition) against Spodoptera littoralis, M. persicae, and Rhopalosiphum padi, respectively, of Hannour et al. [58], who evaluated the properties of rosemary EO collected from two different sites and obtained superior results for EO richer in oxygenated monoterpenes.

In their 2019 study, Pavela et al. [60] encapsulated EOs of Pimpinella anisum, Trachyspermum ammi, and Crithmum maritimum into microemulsions, as effective mosquito larvicides. Their study (on C. quinquefasciatus, a known vector of Wuchereria bancrofti, avian malaria, and several arboviruses, including Zika or West Nile viruses) showed toxicity against the larvae (registering high larval mortality and low percentage hatched adults). Satyal et al. [61] evaluated the Severinia monophylla EO as a larvicidal agent (against Aedes mosquito) and insect repellent (against Triatoma rubrofasciata). Their results showed good larvicidal activity of EOs, as well as repellent activity at a concentration of 0.5%. The larvicidal activity of several EOs was also evaluated by Huang et al. [62] and Scalvenzi et al. [63] against the mosquito species C. quinquefasciatus, A. albopictus, and A. aegypti, whereas other studies identified the insecticidal potential of EOs against Rhodnius prolixus nymphs (vector of Chagas disease) and Cimex lectularius (bed bug) [64], [65]. Regarding the agricultural pests, several studies evaluated the insecticidal role of EOs against Aphis pomi DeGeer [66], Ips typographus [67], S. oryzae [68], L. bostrychophila, and T. castaneum [69], respectively, and T. castaneum and L. serricorne [70]. Noteworthy is the study performed by Cao et al. [70], who evaluated the differences in terms of insecticidal and insect repellent activity of EO obtained from different parts of Haplophyllum dauricum (L.) G. Don (fruits, stems, leaves) harvested in different months (October and November). The authors assign the repellent activity to the content in oxygenated monoterpenes and the insecticidal effect to their monoterpene content.

The presented examples do not intend to exhaustively review all the articles published in the selected time period on the topic of EO applications as insecticides and insect repellents, but to paint a picture of recent developments on this topic, briefly presenting the targeted pests and the results obtained, results that allow the perspective of developing of “green” insecticides (valuable for the agricultural domain in special) and pest repellents (valuable tools in the context of serious illnesses of which various insects are vectors). The insecticidal potential of the described EOs was often found to be superior to the commercial synthetic insecticides, at very low concentrations (generally <1% EO concentration; Table 1). The mechanisms of action of EOs as insecticidal agents represent a topic of interest and current debate. Starting from the fact that most monoterpenes are toxic to plants and animal tissues, many authors assign the main role in EOs’ insecticidal action to these compounds. The mechanism through which EOs act as insecticidal or insect repellent agent is also different, considering the method of application: for direct contact, the most probable mechanism is through a neurotoxic action [71]; for fumigant application, the most probable mechanism is through the action of monoterpenoids on the respiratory system [18], whereas for the repellent activity, the exact mechanisms through which EOs act still remain unclear, considering the differences between the olfactory receptors of insects, despite the relatively high number of studies on this topic [18].

3 Herbicidal properties of EOs

One important category of pesticides, both synthetic and natural, is the herbicides. As in the case of insecticides, the extensive use of synthetic herbicide can lead to a wide range of toxic effects both on the environment and fauna [72], [73]. These potential harmful effects led in turn to the development of alternative, “greener” herbicides, either of microbial or plant origin [74], [75]. Although EO-based herbicides could help overcome many disadvantages of the synthetic products, some of the chemical and physical properties of EOs can prove to be impediments, such as high volatility and low water solubility [76].

Blázquez and Carbó [77] used boldo EO (compared with a commercially available lemon EO) as an efficient herbicide against Portulaca oleracea (a highly adaptable weed encountered on the summer crops). The herbicidal effect was tested by the authors against weed seeds, evaluating the germination of the seeds when exposed to EOs. If the commercial lemon EO does not affect the germination, the boldo EO induced complete inhibition of the germination at 0.5 and 1 mL/L concentration in some growth conditions (details presented in Table 2). Fouad et al. [78] evaluated the herbicidal effect of EOs obtained from four plants cultivated in Morocco against wild mustard (a weed especially affecting the cereals and row crops). The best results were obtained for Cymbopogon citratus, which provided 100% inhibition at a 0.4 mL/L dose (EO in 1:1 twin:water solution), much superior to the commercial herbicides 2.4 D (for which the same inhibition was achieved for a 2 mL/L concentration) and glyphosate (36.5% inhibition at a 1 mL/L concentration). Mahdavikia and Saharkhiz [79] evaluated the herbicidal potential of peppermint EO against three common weeds: field bindweed, purslane, and jungle rice. Their study showed complete inhibition of purslane and jungle rice (at concentrations of 1.8 mL/L, respectively, 1.2 mL/L), but also revealed the lack of selectivity, as also inhibiting the germination of tomato and radish seeds. Ali et al. [80] proposed the potential use of Thymus algeriensis Boiss. et Reut. EO obtained from different parts of plants, using Medicago sativa L. and Triticum aestivum L. as plant models.

Table 2:

Origin and major composition of the essential oils presented in the review with herbicidal effect.

Plant materialMajor composition (%)Targeted pestEffect quantificationRef.
Peumus boldus Mol. leavesAscaridole (31.56), p-cymene (21.58), 1,8-cineole (12.57), by GC-MSPortulaca oleracea L.PSG=0 (paper/sand/clay soilless culture and silty clay soil), 9 (loam soil), 47.5 (sandy clay)[77]
Cymbopogon citratus (DC) StapfNeral (29.2), geranial (18.2), α-pinene (4.8), by GC-MSSinapis arvensis L.PSG=0 at 0.4 mL/L EO[78]
Eucalyptus cladocalyxSpathulenol (21.6), 1,8-cineole (20.5), p-cymene (15.1), by GC-MSSinapis arvensis L.PSG=0 at 1 mL/L EO[78]
Origanum vulgare L.Carvacrol (34.0), γ-terpinene (21.6), p-cymene (9.4), by GC-MSSinapis arvensis L.PSG=0 at 2 mL/L EO[78]
Artemisia absinthium L.β-Thujone (35.6), chamazulene (3.1), linalool (1.9), by GC-MSSinapis arvensis L.PSG=0 at 2 mL/L EO[78]
Mentha×piperita L. CV. MitchamMenthol (35), mentone (17.48), menthofuran (11.7), by GC-MSConvolvulus arvensis L., Portulaca oleracea L., Echinochloa colonum L.PSG=0 at 1.2 mL/L (P.o.) at 1.8 mL/L (E.c.), 23.5 at 1.8 mL/L (C.a.)[79]
Thymus algeriensis Boiss. et Reut. leavesα-Pinene (13.6–23.2),1,8-cineole (7.4–17.8), caryophyllene oxide (4.3–17.8), by GC-MSMedicago sativa L., Triticum aestivum L.PSG=0, at 1 mg/mL concentration[80]
Cullen plicata (Delile) C.H. Stirt. aerial parts(−)-Caryophyllene oxide (33.42), Z-nerolidol (17.92), epi-cadinol (9.06), by GC-MSBidens Pilosa, Urospermum picroidesPSG=0, at 200 μg/L concentration[81]
Origanum onites L.Carvacrol (57.1), linalool (8.39), p-cymene (7.86), by GC-MSAvena sterilis, Sinapis arvensisPSG=0 at 4 μL EO/Petri dish[82]
Rosmarinus officinalis L.1,8-Cineole (21.45), camphor (19.7), borneol (8.58), by GC-MSAvena sterilis, Sinapis arvensisPSG=0 at 4 μL EO/Petri dish (S.a.) and <15% at 16 μL EO/Petri dish A.a[82]
Tetraclinis articulata (Vahl.) Mastersα-Pinene (56.21), β-myrcene (3.08), 1,8-cineole (9.91), GC-MSSinapis arvensis L., Phalaris canariensis L.PSG=0 (S.a.) at 4 mL/L, 6.66 (P.c.) at 3 mL/L[83]
Different genotypes of Myrtus communis L. fruits1,8-Cineole (29.20–31.40), linalool (15.67 –19.13), α-terpineol (8.40– 18.43), α-pinene (6.04–20.71), by GC-MSAmaranthus retroflexus L., Chenopodium album L., Cirsium arvense (L.) Scop., Lactuca serriola L., Rumex crispus L.Best results: PSG=0 for 1 mg/mL (A.r., C.a., L.s.), <5 (Ch.a.), <35 (R.c.), superior to 2,4 D[84]
Cupressus macrocarpa HartwegThujene (15.35), citronellal (11.09), farnesol (9.9), by GC-MSDactyloctenium australe L., Amaranthus hybridus L.PSG=0 at 5 mL/L EO in laboratory, 13/10.8 in pot culture[85]
Murraya koenigii (L.) SprengCaryophyllene (30.21), selinene (12.09), α-humulene (11.23), by GC-MSDactyloctenium australe L., Amaranthus hybridus L.PSG>40% in laboratory, >50% in pot culture, at 5 mL/L EO[85]
Plectranthus amboinicus (L.) SprengCarvacrol (27.11), caryophyllene (16.6), α-humulene (10.23), by GC-MSDactyloctenium australe L., Amaranthus hybridus L.PSG>50% in laboratory, >55% in pot culture, at 5 mL/L EO[85]
Persicaria odorata (L.) SojakDodecanal (31.66), decanal (21.47), 1-decanol (8.12), by GC-MSDactyloctenium australe L., Amaranthus hybridus L.PSG<10% in laboratory, >30% in pot culture, at 5 mL/L EO[85]
Pelargonium radula (Cav.)cis-Geraniol (31.16), γ-eudesmol (10.84), geranyl tiglate (8.49), by GC-MSDactyloctenium australe L., Amaranthus hybridus L.PSG=0 at 5 mL/L EO in laboratory, 9/6.7 in pot culture[85]
Twenty Asteraceae speciesOxygenated monoterpenes, monoterpenes hydrocarbons, sesquiterpenes hydrocarbons, heterogeneous among species, individual components identified by GC-EIMSAmaranthus retroflexus, Setaria viridisBest results PSG=0 (Artemisia annua, Artemisia verlotiorum, Xanthium strumarium, against A.r., at 10 μg/L, Artemisia annua, Xanthium strumarium, against S.v., at 100 μg/L)[86]
Nepeta nuda subsp. albiflora aerial parts4aα,7α,7α,β-Nepetalactone (74.27), 2(1H)-naphthalenone, octahydro-8a-Methyl-trans- (10.09), trans-caryophyllene (1.98), by GC-MSPortulaca oleraceaPSG=14% at mL/L[87]
Citrus aurantiifolia leavesLimonene (40.92), citral (27.46), geranyl acetate (4.67), by GC-MSAvena fatua, Echinochloa crus-galli, Phalaris minorPSG=0 at 1 mg/mL (A.f.), 1.5 mg/mL (E.c-g.), 0.75 mg/mL (P.m.)[88]
Satureja hortensis L. aerial partsCarvacrol (55.6), γ-terpinene (31.9), α-terpinene (3.75), by GC-MSAmaranthus retroflexus, Chenopodium albumPSG=0 (laboratory conditions), 16.6 (greenhouse), at 1 mL/L[89]
Tagetes erecta L. leavesPiperitone (17.12), neophytadiene (16.18), caryophyllene (11.10), by GC-MSEchinochloa crus-galli (L.) Beauv.PSG=0 at 2 mL/L formulation (pre-emergence);

CaC=17.72, CbC=20.99, CC=10.08, at 6 h after treatment, at 80 mL/L formulation foliar application
[90]
Cuminum cyminum L. seedsα-Pinene (29.20), limonene (21.70), 1,8-cineole (18.10), by GC-MSRumex crispus L., Convolvulus arvensis L.PSG=0. at 5 μg/cm2[91]
Mentha longifolia L. leavestrans-Piperidone epoxide (48.70), piperidone oxide (21.20), germacrene D (9.80), by GC-MSRumex crispus L., Convolvulus arvensis L.PSG=0 at 5 μg/cm2[91]
Allium sativum L. bulbsDiallyl trisulfide (33.40), diallyl disulfide (20.80), allyl methyl trisulfide (19.20), by GC-MSRumex crispus L., Convolvulus arvensis L.PSG=0 (C.a.) at 5 μg/cm2; 0 (R.c.) at 10 μg/cm2[91]
Rosmarinus officinalis L. leaves and flowers1,8-Cineole (54.6), camphor (12.27), α-pinene (7.09), by GC-MSTrifolium incarnatum, Silybum marianum, Phalaris minorPSG=0 at 5 mM (pre-emergence);

HA=71.3/18/46.33 at 3.4% formulated EO (foliar application)
[92]
Hyptis suaveolens leavesα-Phellandrene (22.8), α-pinene (10.1), limonene (8.5), by GC-MSEchinochloa crus-galliPSG=0 at 2 mg/mL (pre-emergence);

VI=100% after 21 days of spray, 5% formulated EO (foliar application)
[93]
Eucalyptus citriodora HookCitronellal (73.6), isopulegol (4.5), citronellol (2.6), by GC-MSAngallis arvensis, Cyperus rotundus, Cynodon dactylonA.a.–VI=100% after 7 days, at 50 mM, after 1 day at 100 mM; C.r.–VI=70% 1st day, second spray at 100 mM; C.d.–VI=>80% 1st day, second spray, at 150 mM[76]
Ocimum basilicum L.Methyl chavicol (71.2), linalool (24), geranial (18.9), by GC-MSAngallis arvensis, Cyperus rotundus, Cynodon dactylonA.a.–VI=100% after 7 days, at 50 mM, after 1 day at 100 mM; C.r.–VI=80% 7 days, second spray at 100 mM; C.d.–VI=100% 7 days, third spray, at 150 mM[76]
Mentha arvensis L. leavesMenthol (60.13), menthone (11.83), iso-methanone (5.46), by GC-MSAngallis arvensis, Cyperus rotundus, Cynodon dactylonA.a.–VI=100% after 7 days, at 50 mM, after 1 day at 100 mM; C.r.–VI=100% 1st day, second spray at 100 mM; C.d.–VI=100% 7 days, first spray at 150 mM[76]

  1. All EOs were obtained by water distillation/steam distillation. Entries are ordered chronologically. CaC, Chlorophyll a content; CbC, chlorophyll b content; CC, carotenoid content; H, herbicidal; HA, herbicidal activity; GC-MS, gas chromatography-mass spectrometry; PSG, percentage seed germination; VI, visible injury.

In his 2016 study, El-Gawad [81] evaluated the herbicidal potential of EO obtained from the aerial parts of Cullen plicata (Delile) C.H. Stirt. against Bidens pilosa and Urospermum picroides, whereas Atak et al. [82] used oregano and rosemary EO as herbicides against Avena sterilis and Sinapis arvensis. Ghnaya et al. [83] evaluated Tetraclinis articulata (Vahl.) Masters. EO against S. arvensis L. and Phalaris canariensis L., whereas Kordali et al. [84] used EOs obtained from four myrtle genotypes on Amaranthus retroflexus L., Chenopodium album L., Cirsium arvense (L.) Scop., Lactuca serriola L., and Rumex crispus L. In the same year, Almarie et al. [85] evaluated a series of EOs extracted from Malaysian plants against Amaranthus hybridus and Dactyloctenium australe, the best results being obtained for Cupressus macrocarpa and Pelargonium radula EOs.

In a 2017 study, Benvenuti et al. [86] evaluated 20 EOs extracted from Asteraceae species collected in Tuscany as natural herbicides against A. retroflexus and Setaria viridis, the best results being obtained for EOs of Artemisia annua, Artemisia verlotiorum, and Xanthium strumarium against A. retroflexus (0% germination at 10 μg/L EO), respectively, for A. annua and X. strumarium against S. viridis (0% germination at 100 μg/L EO). Bozok et al. [87] evaluated EOs obtained from the aerial parts of Nepeta nuda subsp. albiflora against P. oleracea, whereas Fagodia et al. [88] used Citrus aurantiifolia EO as herbicide against Avena fatua, Echinochloa crus-galli, and Phalaris minor. In the same year, Hazrati et al. [89] formulated nanoemulsion containing Satureja hortensis L. EO (2%) and evaluated its herbicidal activity against A. retroflexus and C. album, with good efficiency, both in laboratory and greenhouse conditions.

In a 2018 study, Laosinwattana et al. [90] used Tagetes erecta L. EO formulated as emulsifiable concentrate (50%) as herbicidal agent against E. crus-galli (L.) Beauv., applied both pre- and post-emergence. The pre-emergence application led to a complete inhibition, that the authors assign to the inhibition of α-amylase activity, whereas the post-emergence application led to the degradation of the weed (wilted and desiccated appearance, decreased chlorophyll a, chlorophyll b, and carotenoid content), assigned to the interference of the herbicide with the photosynthetic metabolism. In the same year, Üstüner et al. [91] applied EOs obtained from Cuminum cyminum L., Mentha longifolia L., and Allium sativum L. as herbicidal agents against R. crispus L. and Convolvulus arvensis L., two widely encountered crop weeds. Their results showed remarkable inhibition of the seed germination at almost all tested concentrations.

Kaab et al. [92] used EO obtained from the leaves and flowers of Rosmarinus officinalis L. as herbicidal agent in a formulation containing 3.4% EO against the weeds Trifolium incarnatum, Silybum marianum, and P. minor obtaining a complete seed germination inhibition at 5 mM EO concentration. Sharma et al. [93] used Hyptis suaveolens EO as herbicidal agent (pre- and post-emergence) against E. crus-galli (the major weed of rice). More than the very good herbicidal results, it is to be noticed that the formulation containing EO shows good selectivity to the weed (60% germination of the rice, compared with 0% for the weed at 2 mg/mL EO concentration), thus allowing the practical use of the herbicide for the protection of rice culture. In the same year, Khare et al. [76] evaluated the herbicidal impact of three EOs (Eucalyptus citriodora Hook, Ocimum basilicum L., and Mentha arvensis L.) formulated as emulsions against Angallis arvensis, Cyperus rotundus, and Cynodon dactylon, in greenhouse conditions. The most promising material (from the obtained results) was the formulation containing M. arvensis EO, which at 100- to 150-mM concentration and different foliar application conditions led to 100% visible injuries (weed death).

When considering the use of EOs as a potential herbicide, one of the most important aspects is the selectivity, as the formulation should affect mainly the weeds and not the crops, as demonstrated by Sharma et al. [93]. The general mechanism through which EOs act as herbicides is considered to be inhibition of mitochondrial respiration, accompanied by damages induced to the membrane integrity (increasing membrane permeability), and oxidative stress, affecting pH homoeostasis and equilibrium of inorganic ions [86].

4 Application of EOs as acaricidal and nematicidal agents

In close connection to their insecticidal potential, the natural extracts and EOs can be applied as acaricidal agents. The Acari, in its largest sense, refers to mites and ticks, both types of arachnids having economical and medical importance, affecting multiple crops types, as well as representing vectors for a large number of diseases [94], [95], [96]. In the last years, several review articles described the use of natural alternatives to the synthetic acaricides [97], [98], [99], works that we recommend for further reading. As the Acari, the nematodes represent important pests, affecting both the agricultural and horticultural crops, but also affecting the livestock and human health [100], [101].

Zandi-Sohani and Ramezani [102] evaluated in 2015 five EOs (S. hortensis L., Mentha pulegium L., Mentha viridis L., R. officinalis L., Zataria multiflora Bioss.) as acaricidal solutions against Tetranychus turkestani Ugarov and Nikolskii (strawberry spider mite). The best results were obtained for Z. multiflora, with an LC50 value of 5.5 μL/L air (fumigant assay) and 100% mortality at 24-h exposure time to 12 μL/L EO. The acaricidal effect against Rhipicephalus (Boophilus) microplus (a thick that parasites multiple livestock species) of EOs obtained from different Ocimum species was studied by Hüe et al. [103], the best results being obtained for Ocimum urticaefolium and O. gratissimum originating from Cameroon. The same tick was used by Costa-Júnior et al. [104], Monteiro et al. [105], and Vinturelle et al. [106] to test the acaricidal effect of EOs isolated from Lippia gracilis, Cinnamomum verum Presl, respectively, Piper nigrum, and Citrus limonum (further details presented in Table 3). While Costa-Júnior et al. [104] assigned the acaricidal effect of EOs to the monoterpenes present, especially carvacrol and thymol, Vinturelle et al. [106] compared the efficiency of two different composition EOs (C. limonum dominated by monoterpenes, respectively, P. nigrum dominated by sesquiterpenes), obtaining superior results for the C. limonum EO, thus suggesting a more potent acaricidal effect related to the presence of monoterpenes.

Table 3:

Origin and major composition of the essential oils presented in the review with acaricidal and nematicidal effect.

EffectPlant materialMajor composition (%)Targeted pestEffect quantificationRef.
ASatureja hortensis L.Carvacrol (38.33), γ-terpinene (22.72), p-cymene (9.55), by GC-MSTetranychus turkestani Ugarov and NikolskiiLC50=9.4 μL/L air; LC90=31.3 μL/L air(fumigant);

MR=100% at 24 h, 12 μL/L
[102]
AMentha pulegium L.Piperitone (32.16), piperitenone (29.62), α-terpineol (6.4), by GC-MSTetranychus turkestani Ugarov and NikolskiiLC50=14.5 μL/L air; LC90=19.9 μL/L air (fumigant);

MR=100% at 24 h, 20 μL/L
[102]
AMentha viridis L.Carvone (51.03), limonene (21.12), cis-dihydrocarvone (3.23), by GC-MSTetranychus turkestani Ugarov and NikolskiiLC50=15.3 μL/L air; LC90=23.4 μL/L air (fumigant);

MR=100% at 24 h, 20 μL/L
[102]
ARosmarinus officinalis L.Borneol (21.17), α-pinene (15.17), α-terpineol (7.54), by GC-MSTetranychus turkestani Ugarov and NikolskiiLC50=29.8 μL/L air; LC90=35.6 μL/L air (fumigant);

MR=91.1% at 24 h, 17 μL/L
[102]
AZataria multiflora BiossThymol (30.61), carvacrol (22.18), p-cymene (7.34), by GC-MSTetranychus turkestani Ugarov and NikolskiiLC50=5.5 μL/L air; LC90=11.8 μL/L air (fumigant);

MR=100% at 24 h, 12 μL/L
[102]
AOcimum gratissimum L.–Cameroonγ-Terpinene (33), thymol (30.5), p-cymene (7), by GC-MSRhipicephalus (Boophilus) microplusMR at 2.5% EO=100

LC50=0.98%
[103]
AOcimum gratissimum L.–New Caledonia(Z)-β-ocimene (49.8), eugenol (22,3), β-caryophyllene (4.7), by GC-MSRhipicephalus (Boophilus) microplusMR at 5% EO=65.17[103]
AOcimum urticaefolium RothEugenol (33), β-bisabolene (21.6), elemicin (18.1), by GC-MSRhipicephalus (Boophilus) microplusMR at 2.5% EO=100

LC50=0.90%
[103]
AOcimum canum Sims leaves1,8-Cineole (70.2), β-pinene (5.7), α-terpineol (4), by GC-MSRhipicephalus (Boophilus) microplusMR at 5% EO=0[103]
ALippia gracilis Schauer leaves genotype 106Thymol (59.26), β-caryophyllene (8.57), methylthymol (8.32), by GC-MSRhipicephalus (Boophilus) microplus susceptible

and organophosphate-resistant larvae
LC50=1.02 (susceptible strain), 0.84 mg/mL (resistant strain)[104]
ALippia gracilis Schauer leaves genotype 201Carvacrol (35.28), γ-terpinene (21.11), p-cymene (13.74), by GC-MSRhipicephalus (Boophilus) microplus susceptible

and organophosphate-resistant larvae
LC50=1.03 (susceptible strain), 0.65 mg/mL (resistant strain)[104]
ACinnamomum verum Presl leavesBenzyl benzoate (65.4), linalool (5.4), E-cinnamaldehyde (4.0), by GC-MSRhipicephalus (Boophilus) microplusLC50=1 mg/mL (larvae) and 60.78 mg/mL (engorged female)[105]
APiper nigrumβ-Caryophyllene (26.2), σ-ocymene (5.8), α-pinene (5.5), by GC-MSRhipicephalus (Boophilus) microplusLC50=3.70%;

LC90=14.80%

MR=81.7% at 10% EO
[106]
ACitrus limonumLimonene (50.3), β-pinene (14.4), γ-terpinene (11.7), by GC-MSRhipicephalus (Boophilus) microplusLC50=2.2%;

LC90=4.9%

MR=100 at 10% EO
[106]
ACinnamomum zeylanicum bark - FranceCinnamaldehyde (63.97), eugenol (6.84), cinnamyl acetate (3.90), by GC-MSDermatophagoides farinae, Dermatophagoides pteronyssinus, Tyrophagus putrescentiaeLD50=0.92/0.81/1.82 μg/cm3 (fabric disk); 2.07/1.94/6.20 μg/cm2 (F) (paper assay)[107]
ACinnamomum zeylanicum bark - IndiaCinnamaldehyde (67.21), eugenol (19.79), cinnamyl acetate (4.34), by GC-MSDermatophagoides farinae, Dermatophagoides pteronyssinus, Tyrophagus putrescentiaeLD50=0.64/0.51/1.72 μg/cm3 (India) (fabric disk); 1.82/1.55/3.08 μg/cm2 (paper assay)[107]
AFerula gumosa Boiss. Resinsβ-Pinene (50.1), α- pinene (14.9), δ-3-carene (6.7), by GC-MSTetranychus urticae KochLC50=6.98/6.52 μL/L (eggs/adults) (fumigant)[108]
ALippia gracilis leavesCarvacrol (61), p-cymene (11), thymol (11), by GC-MSTetranychus urticae KochLC50=0.06 μL/L air (fumigant), LC50=29.7 μL/L air (residual effect)[109]
ACupressus macrocarpa Hartw. ex Gordon

Terpinen-4-ol (20.29), sabinene (18.67), β-citronellol (13.01), by GC-MSTetranychus urticae KochLC50=40.66 mg/L air (fumigant, 24 h), 17.39 mg/L air (slide dip, 48 h)[110]
ACallistemon viminals (Sol. ex Gaertn.) G. Don1,8-Cineole (71.77), α-pinene (11.47), terpinen-4-ol (3.18), by GC-MSTetranychus urticae KochLC50=5.69 mg/L air (fumigant, 24 h), 22.76 mg/L air (slide dip, 48 h)[110]
AOriganum vulgare L.Pulegone (77.45), menthone (4.86), cis-isopulegone (2.22), by GC-MSTetranychus urticae KochLC50=8.52 mg/L air (fumigant, 24 h), 10.26 mg/L air (slide dip, 48 h)[110]
APelargonium graveolens L’Herβ-Citronellol (35.92), geraniol (11.66), citronellylformate (11.40), by GC-MSTetranychus urticae KochLC50=12.27 mg/L air (fumigant, 24 h), 23.83 mg/L air (slide dip, 48 h)[110]
AThuja orientalis L. leavesα-Pinene (35.49), δ-3-carene (25.42), α-cedrol (9.05), by GC-MSTetranychus urticae KochLC50=7.51 mg/L air (fumigant, 24 h), 114.46 mg/L air (slide dip, 48 h)[110]
ACitrus paradisi Macfad peelLimonene (74.29), linalool (4.61), linalool oxide (4.18), by GC-MSTetranychus urticae KochLC50=6.96 mg/L air (fumigant, 24 h), 160.75 mg/L air (slide dip, 48 h)[110]
ACitrus aurantiifolia peelsLimonene (37.73), β-pinene (9.89), α-terpineol (5.04), by GC-MSTetranychus urticae KochLC50=11.24 μL/L air (fumigation); 106.14 mL/L (residual)[111]
ACitrus limon peelsLimonene (40.70), β-pinene (18.14), α-fenchene (3.84), by GC-MSTetranychus urticae KochLC50=9.34 μL/L air (fumigation); 25.18 mL/L (residual)[111]
ACitrus reticulata peelsLimonene (77.79), myrcene (6.50), linalool (3.56), by GC-MSTetranychus urticae KochLC50=6.09 μL/L air (fumigation); 167.8 mL/L (residual)[111]
ACitrus reticulata×Citrus sinensis peelsLimonene (60.96), p-mentha-2,4(8) -diene (9.8), myrcene (4.61), by GC-MSTetranychus urticae KochLC50=10.39 μL/L air (fumigation); 159.75 mL/L (residual)[111]
ASchinus molle L. fruitsp-Cymene (40.0), limonene (19.5), myrcene (7.7), by GC-MSRhipicephalus sanguineusMR=99.31 at 2% EO (larvae), IOv=29.62%, EH=59.43%, 22.61% at 2% EO (adults)[112]
NArtemisia herba-albaCamphor (25.88), cis-thujone (24.95), trans-thujone (16.26), by GC-MSMeloidogyne incognita,

Pratylenchus vulnus, Xiphinema index
MR=97.5 (M.i. at 48 h, 15 mg/L), 100 (X.i. at 24 h, 2 mg/L), 67 (P.v. at 96 h, 15 mg/L);

68.2% reduction of nematodes/g roots at 200 μg/kg soil (fumigation); 65.5% reduction at 100 μg/kg soil (drench)
[113]
NCitrus sinensis

Limonene (95.6), β-myrcene (1.96), α-pinene (0.54), by GC-MSMeloidogyne incognita,

Pratylenchus vulnus, Xiphinema index
MR=39.2/18.2/73.2 at 96 h, 15 mg/L;

46.7% reduction of nematodes/g roots at 200 μg/kg soil (fumigation); 61.18% reduction at 100 μg/kg soil (drench)
[113]
NRosmarinus officinalis1,8-Cineole (47), α-pinene (14.55), camphor (12.07), by GC-MSMeloidogyne incognita,

Pratylenchus vulnus, Xiphinema index
MR=100 (X.i. at 24 h, 2 mg/L), 98.3/75.2 at 96 h, 15 mg/L (M.i., P.v.)

67.5% reduction of nematodes/g roots at 200 μg/kg soil (fumigation); 56.74% reduction at 100 μg/kg soil (drench)
[113]
NThymus satureioidesBorneol (29.31), thymol (11.76), o-cymene (6.78), by GC-MSMeloidogyne incognita,

Pratylenchus vulnus, Xiphinema index
MR=100 (X.i. at 24 h, 2 mg/L), 85.7/39.9 (M.i., P.v.) at 96 h, 15 mg/L (in vitro);

53.89% reduction of nematodes/g roots at 200 μg/kg soil (fumigation); 60.17% reduction at 100 μg/kg soil (drench)
[113]
NTagetes zypaquirensisDihydrotagetone (42.2), tagetone (22.9), trans-ocimene (20.8), by GC-FID, GC-MSMeloidogyne spp.52% reduction of eggs/100 g roots; 42% reduction of stage 2 juvenils/100 g of soil[114]
NDysphania ambrosioides aerial parts(Z)-ascaridole (87.3), (E)-ascaridole (8.4), p-cymene (3.3), by GC-MSMeloidogyne incognitaLC50=307 mg/L; LC90=580 mg/L (in vitro);

Significant reduction of galls and eggs at 800 mg/L, respectively, 1100 mg/L
[115]

  1. All EOs were obtained by water distillation/steam distillation. Entries are ordered chronologically. A, Acaricidal; EH, egg hatching; GC-MS, gas chromatography-mass spectrometry; IOv, inhibition of oviposition; LC50, lethal concentration that kills 50% of the exposed organisms; LC90, lethal concentration that kills 90% of the exposed organisms; MR, mortality rate; N, nematicidal.

Jeon et al. [107] used EO obtained from Cinnamomum zeylanicum bark cultivated in France and India as acaricidal agents against Dermatophagoides spp. and Tyrophagus putrescentiae mites, offering the possibility to develop natural acaricides against the dust and stored food mites. Fatemikia et al. [108] applied the EO obtained from Ferula gummosa Boiss. as acaricidal agent against the plant-feeding mite Tetranychus urticae Koch., showing toxicity against the eggs and adults, as well as oviposition deterrent and repellent activity. Good results (LC50=0.06 mL/L air) were also obtained by Born et al. [109] against the same mite species, using L. gracilis EO; the results also proved a high selectivity towards the tested mite, compared with its natural enemy, Neoseiulus californicus. Similar results were also obtained by Mahmoud et al. [110] and Ribeiro et al. [111]. Rey-Valeirón et al. [112] used Schinus molle EO against Rhipicephalus sanguineus (brown tick of the dog) larvae and engorged adult females, obtaining superior results compared with the control acaricide used (cypermethrin).

Similar with the insecticidal potential, the acaricidal potential of EOs is usually assigned by the authors to their monoterpenes content [104], and more than that, those monoterpenes components (such as carvacrol or thymol) were proposed as efficient agents against the metabolic resistance mechanisms or insensitive acetylcholinesterases (AChE) in the case of organophosphate resistant Acari [104].

Avato et al. [113] used EOs obtained from Moroccan ecotypes of Artemisia herba-alba, Citrus sinensis, R. officinalis, and Thymus satureioides for the control of the phytonematodes M. incognita, Pratylenchus vulnus, and Xiphinema index, whereas Álvarez et al. [114] used EO extracted from the leaves and inflorescences of Tagetes zypaquirensis against Meloidogyne spp. (further details presented in Table 3). Barros et al. [115] used EO of Dysphania ambrosioides aerial parts (formulated in aqueous Tween 80 solutions) against Meloidogyne incognita applying in vitro and in vivo assays, observing a significant nematicidal activity, compared with commercial EOs.

The mechanism responsible for the nematicidal action of EOs still represents a subject of debate. Avato et al. [113] propose as most probable action of EOs the permeability change of nematode cell membranes or the inhibition of AChE activity (as already observed for insects), whereas Barros et al. [115] observed the neurotoxicity effects of EOs on nematodes.

5 Current limitations and future perspectives

The application of EOs current represents an attractive area of research, focusing especially on their potential insecticidal and herbicidal potential (covered by the present article; Figure 3), as well as on their antibacterial, antifungal, and antiviral potential (not covered by the review), based on the properties of constituent compounds. Several databases regarding the composition of EOs and the toxicity of the individual compounds are available to the public [117], [118], constituting an important instrument for specialists working in this area. A closer look at progress in the last years can offer the first key perspective: the study on the pesticidal applications of EOs should also focus on other areas (insufficiently explored up to date), such as their applications as rodenticidal/rodent repellent or algicidal agents.

Figure 3: General pathways of EOs’ pesticide action (adapted from Mossa [18], Benvenuti et al. [86], and El-Hadary and Chung [116]).

Figure 3:

General pathways of EOs’ pesticide action (adapted from Mossa [18], Benvenuti et al. [86], and El-Hadary and Chung [116]).

Indifferent on their final applications, the selectivity of EOs should be explored. Several works reviewed described the selectivity of the materials used. The proposed pesticides should have a high selectivity (either we are talking about herbicides, insecticides, or other activities) towards the targeted organisms, influencing as little as possible the nontarget organisms.

Another key factor that should be explored in future research is represented by their application methods. Being limited by the physicochemical characteristics of EOs (especially by their volatility and a generally low bioavailability of the active polyphenolic compounds), EOs should usually be formulated as microemulsion or nanoemulsion. The current research is focused on the application of aqueous microemulsions using commercially available surfactants. In this area, the use of natural surfactants could bring a supplementary “green” component. More than that, the application of nanotechnology tools for developing new formulations, using polymer-based nanocapsules, could enhance or encapsulation with metallic nanoparticles could increase the availability of EOs and, at the same time, potentiate their activities.

An important aspect to be considered by future studies is the advantages that can be provided by biotechnology, from the cocultures that can be used for pesticidal screening [119] to engineering plants with higher EO content or richer in biological active terpenoids [120], [121].

Finally, the extraction method of EOs could benefit from the latest technological developments. The reviewed articles used hydrodistillation (either water or steam distillation for isolation of EOs, the method of choice being based on the sensitivity of known compounds in EOs and availability). Other techniques developed in the last years, such as microwave-assisted extraction (with or without solvent) [122] or membrane extraction [123], proved to be efficient for the extraction of EOs and can be used for industrial-scale development of pesticides based on EOs.

6 Conclusions

The captivating field of EOs finds practical applications in numerous areas. Among those areas, the application of EOs for replacing the synthetic pesticides currently used can lead to a tremendous increase in the life quality (by considering the potential toxic effect of the pesticides on the environment and on fauna and human health) and, at the same time, provide an efficient tool for preventing resistance development in the targeted pests. Although several authors proposed some type of compounds (especially monoterpenes and oxygenated monoterpenes) as responsible for the pesticidal effect of EOs, in our opinion, the most probable mechanism is represented by a synergistic action of several compounds found in EOs.

As a concluding remark, EOs, although currently under study for their pesticidal activity, should be further explored, as they can provide important tools in fighting the pests that not only have important economic implications, but can also prove to be vectors of serious illnesses.

Acknowledgements

The authors gratefully acknowledge the support obtained through the project SusMAPWaste, SMIS 104323, contract no. 89/09.09.2016, from the Operational Program Competitiveness 2014–2020, project cofinanced by the European Regional Development Fund.

References

1. Batish DR, Singh HP, Kohli RK, Kaur S. Eucalyptus essential oil as a natural pesticide. Forest Ecol Manag 2008;256:2166–74.10.1016/j.foreco.2008.08.008Suche in Google Scholar

2. Food and Agriculture Organization of the United Nations (FAO). Pesticides. http://www.fao.org/faostat/en/#data/EP/visualize. Accessed: 9 October 2019.Suche in Google Scholar

3. Food and Agriculture Organization of the United Nations (FAO). Pesticides Trade. http://www.fao.org/faostat/en/#data/RT. Accessed: 9 October 2019.Suche in Google Scholar

4. Aktar MW, Sengupta D, Chowdhury A. Impact of pesticides use in agriculture: their benefits and hazards. Interdisc Toxicol 2009;2:1–12.10.2478/v10102-009-0001-7Suche in Google Scholar PubMed PubMed Central

5. Domingues PM, Santos L. Essential oil of pennyroyal (Mentha pulegium): composition and applications as alternatives to pesticides – new tendencies. Ind Crop Prod 2019;139:111534.10.1016/j.indcrop.2019.111534Suche in Google Scholar

6. Kim KH, Kabir E, Jahan SA. Exposure to pesticides and the associated human health effects. Sci Total Environ 2017;575:525–35.10.1016/j.scitotenv.2016.09.009Suche in Google Scholar PubMed

7. Miller AL, Tindall K, Leonard BR. Bioassays for monitoring insecticide resistance. J Vis Exp 2010;46:e2129.10.3791/2129Suche in Google Scholar PubMed PubMed Central

8. Ochoa-Acuňa H, Carbajo C. Risk of limb birth defects and mother’s home proximity to cornfields. Sci Total Environ 2009;407:4447–51.10.1016/j.scitotenv.2009.04.028Suche in Google Scholar PubMed

9. Pimentel D. Environmental and economic costs of the application of pesticides primarily in the United States. Environ Dev Sustain 2005;7:229–52.10.1007/s10668-005-7314-2Suche in Google Scholar

10. Amaral AC, Ramos AS, Pena MR, Ferreira JL, Menezes JM, Vasconcelos GJ, et al. Acaricidal activity of Derris floribunda essential oil and its main constituent. Asian Pac J Trop Biomed 2017;7:791–6.10.1016/j.apjtb.2017.08.006Suche in Google Scholar

11. Bossou AD, Ahoussi E, Ruysbergh E, Adams A, Smagghe G, De Kimpe N, et al. Characterization of volatile compounds from three Cymbopogon species and Eucalyptus citriodora from Benin and their insecticidal activities against Tribolium castaneum. Ind Crop Prod 2015;76:306–17.10.1016/j.indcrop.2015.06.031Suche in Google Scholar

12. Kumar P, Mishra S, Malik A, Satya S. Insecticidal properties of Mentha species: a review. Ind Crop Prod 2011;34:802–17.10.1016/j.indcrop.2011.02.019Suche in Google Scholar

13. Nikolic M, Jovanovic K, Markovc TL, Markovic DL. Chemical composition, antimicrobial and cytotoxic properties of five Lamiaceae essential oils. Ind Crop Prod 2014;61:225–32.10.1016/j.indcrop.2014.07.011Suche in Google Scholar

14. Campos EV, Proença PL, Oliveira JL, Bakshi M, Abhilash PC, Fraceto LF. Use of botanical insecticides for sustainable agriculture: future perspectives. Ecol Indic 2019;105:483–95.10.1016/j.ecolind.2018.04.038Suche in Google Scholar

15. Ju J, Chen X, Xie Y, Yu H, Guo Y, Cheng Y, et al. Application of essential oil as a sustained release preparation in food packaging. Trends Food Sci Technol 2019;92:22–32.10.1016/j.tifs.2019.08.005Suche in Google Scholar

16. Seow YX, Yeo CR, Chung HL, Yuk HG. Plant essential oils as active antimicrobial agents. Crit Rev Food Sci Nutrit 2014;54:625–44.10.1080/10408398.2011.599504Suche in Google Scholar PubMed

17. Isman MB, Miresmailli S, Machial C. Commercial opportunities for pesticides based on plantessential oils in agriculture, industry and consumer products. Phytochem Rev 2011;10:197–204.10.1007/s11101-010-9170-4Suche in Google Scholar

18. Mossa AT. Green pesticides: essential oils as biopesticides in insect-pest management. J Environ Sci Technol 2016;9:354–78.10.3923/jest.2016.354.378Suche in Google Scholar

19. Grand View Research. Essential oils market size, share & trends analysis report by application (cleaning & home, medical, food & beverages, spa & relaxation), by product, by sales channel, and segment forecasts, 2019–2025. Grand View Research, Inc. 2019. Report ID: 978-1-68038-549-6 (187 pages).Suche in Google Scholar

20. Diaz JH. Chemical and plant-based insect repellents: efficacy, safety, and toxicity. Wilderness Environ Med 2016;27:153–63.10.1016/j.wem.2015.11.007Suche in Google Scholar PubMed

21. Akkari H, Ezzine O, Dhahri S, B’chir F, Rekik M, Hajaji S, et al. Chemical composition, insecticidal and in vitro anthelmintic activities of Ruta chalepensis (Rutaceae) essential oil. Ind Crop Prod 2015;74:745–51.10.1016/j.indcrop.2015.06.008Suche in Google Scholar

22. Jalaei Z, Fattahi M, Aramideh S. Allelopathic and insecticidal activities of essential oil of Dracocephalum kotschyi Boiss. from Iran: a new chemotype with highest limonene-10-al and limonene. Ind Crop Prod 2015;73:109–17.10.1016/j.indcrop.2015.04.020Suche in Google Scholar

23. Li HY, Liu XC, Chen XB, Liu QZ, Liu ZL. Chemical composition and insecticidal activities of the essential oil of Clinopodium chinense (Benth.) Kuntze aerial parts against Liposcelis bostrychophila Badonnel. J Food Prot 2015;78:1870–4.10.4315/0362-028X.JFP-15-089Suche in Google Scholar PubMed

24. Sumitha KV, Thoppi JE. Larvicidal efficacy and chemical constituents of O. gratissimum L. (Lamiaceae) essential oil against Aedes albopictus Skuse (Diptera: Culicidae). Parasitol Res 2016;115:673–80.10.1007/s00436-015-4786-3Suche in Google Scholar PubMed

25. Wang DC, Qiu DR, Shi LN, Pan HY, Li YW, Sun JZ, et al. Identification of insecticidal constituents of the essential oils of Dahlia pinnata Cav. against Sitophilus zeamais and Sitophilus oryzae. Nat Prod Res 2015;29:1748–51.10.1080/14786419.2014.998218Suche in Google Scholar PubMed

26. Martínez-Evaristo XC, Borboa-Flores J, Wong-Corral FJ, Cinco-Moroyoqui FJ, Del-Toro-Sánchez CL, de León AG, et al. Insecticidal efficacy and repellency of Oregano (Lippia palmeri) essential oil for control of Sitophilus zeamais and Prostephanus truncatus in stored maize. Southwest Entomol 2015;40:713–20.10.3958/059.040.0410Suche in Google Scholar

27. Aguiar RW, dos Santos SF, da Silva Morgado F, Ascencio SD, de Mendonça Lopes M, Viana KF, et al. Insecticidal and repellent activity of Siparuna guianensis Aubl. (Negramina) against Aedes aegypti and Culex quinquefasciatus. PLoS One 2015;10:e0116765.10.1371/journal.pone.0116765Suche in Google Scholar PubMed PubMed Central

28. de Lira CS, Pontual EV, de Albuquerque LP, Paiva LM, Paiva PM, de Oliveira JV, et al. Evaluation of the toxicity of essential oil from Alpinia purpurata inflorescences to Sitophilus zeamais (maize weevil). Crop Prot 2015;71:95–100.10.1016/j.cropro.2015.02.004Suche in Google Scholar

29. Guo SS, You CX, Liang JY, Zhang WJ, Geng ZF, Wang CF, et al. Chemical composition and bioactivities of the essential oil from Etlingera yunnanensis against two stored product insects. Molecules 2015;20:15735–47.10.3390/molecules200915735Suche in Google Scholar PubMed PubMed Central

30. Haider ZS, Mohan M, Pandey AK, Singh P. Repellent and fumigant activities of Tanacetum nubigenum Wallich. ex DC essential oils against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). J Oleo Sci 2015;64:895–903.10.5650/jos.ess15094Suche in Google Scholar PubMed

31. Wu Y, Zhang WJ, Wang PJ, Yang K, Huang DY, Wei JY, et al. Contact toxicity and repellency of the essential oil of Liriope muscari (DECN.) Bailey against three insect tobacco storage pests. Molecules 2015;20:1676–85.10.3390/molecules20011676Suche in Google Scholar PubMed PubMed Central

32. Yang K, Guo SS, Geng ZF, Du SS, Wang CF, Deng ZW. Contact toxicity and repellency of the essential oil of Dictamnus dasycarpus roots from China against two stored-product insects. Chem Biodivers 2015;12:980–6.10.1002/cbdv.201400262Suche in Google Scholar PubMed

33. You C, Guo S, Zhang W, Yang K, Geng Z, Du S, et al. Identification of repellent and insecticidal constituents from Artemisia mongolica essential oil against Lasioderma serricorne. J Chem 2015;2015:549057.10.1155/2015/549057Suche in Google Scholar

34. Zhang WJ, Yang K, You CX, Wang CF, Geng ZF, Su Y, et al. Contact toxicity and repellency of the essential oil from Mentha haplocalyx Briq. against Lasioderma serricorne. Chem Biodivers 2015;12:832–9.10.1002/cbdv.201400245Suche in Google Scholar PubMed

35. Govindarajan M, Rajeswary M, Benelli G. Chemical composition, toxicity and non-target effects of Pinus kesiya essential oil: an eco-friendly and novel larvicide against malaria, dengue and lymphatic filariasis mosquito vectors. Ecotoxicol Environ Safe 2016;129:85–90.10.1016/j.ecoenv.2016.03.007Suche in Google Scholar PubMed

36. Liu XC, Liu SL, Liu ZL. GC-MS analysis of the essential oil and insecticidal activity of Teucrium quadrifarium Buch.-Ham. (Lamiaceae) aerial parts against Liposcelis bostrychophila. J Essent Oil Bear Pl 2016;19:1794–800.10.1080/0972060X.2016.1141067Suche in Google Scholar

37. Liu XC, Lu XN, Liu QZ, Liu ZL. Chemical composition and insecticidal activity of the essential oil of Cyperus rotundus rhizomes against Liposcelis bostrychophila (Psocoptera: Liposcelididae). J Essent Oil Bear Pl 2016;19:640–7.10.1080/0972060X.2014.963168Suche in Google Scholar

38. Zhao MP, Liu XC, Lai D, Zhou L, Liu ZL. Analysis of the essential oil of Elsholtzia ciliate aerial parts and its insecticidal activities against Liposcelis bostrychophila. Helv Chim Acta 2016;99:90–4.10.1002/hlca.201500232Suche in Google Scholar

39. Abdelli M, Moghrani H, Aboun A, Maachi R. Algerian Mentha pulegium L. leaves essential oil: chemical composition, antimicrobial, insecticidal and antioxidant activities. Ind Crop Prod 2016;94:197–205.10.1016/j.indcrop.2016.08.042Suche in Google Scholar

40. Sadeghi A, Pourya M, Smagghe G. Insecticidal activity and composition of essential oils from Pistacia atlantica subsp. kurdica against the model and stored product pest beetle Tribolium castaneum. Phytoparasitica 2016;44:601–7.10.1007/s12600-016-0551-0Suche in Google Scholar

41. Jiang H, Wang J, Song L, Cao X, Yao X, Tang F, et al. GC×GC-TOFMS analysis of essential oils composition from leaves, twigs and seeds of Cinnamomum camphora L. Presl and their insecticidal and repellent activities. Molecules 2016;21:423.10.3390/molecules21040423Suche in Google Scholar PubMed PubMed Central

42. Kerdudo A, Gonnot V, Ellong EN, Boyer L, Chandre F, Adenet S, et al. Composition and bioactivity of Pluchea carolinensis (Jack.) G. essential oil from Martinique. Ind Crop Prod 2016;89:295–302.10.1016/j.indcrop.2016.04.076Suche in Google Scholar

43. Pinto JJ, Silva G, Figueroa I, Tapia M, Urbina A, Rodríguez JC, et al. Insecticidal activity of powder and essential oil of Cryptocarya alba (Molina) Looser against Sitophilus zeamais Motschulsky. Chilean J Agric Res 2016;76:48–54.10.4067/S0718-58392016000100007Suche in Google Scholar

44. Guo S, Zhang W, Liang J, You C, Geng Z, Wang C, et al. Contact and repellent activities of the essential oil from Juniperus formosana against two stored product insects. Molecules 2016;21:504.10.3390/molecules21040504Suche in Google Scholar PubMed PubMed Central

45. Liang JY, You CX, Guo SS, Zhang WJ, Li Y, Geng ZF, et al. Chemical constituents of the essential oil extracted from Rhododendron thymifolium and their insecticidal activities against Liposcelis bostrychophila or Tribolium castaneum. Ind Crop Prod 2016;79:267–73.10.1016/j.indcrop.2015.11.002Suche in Google Scholar

46. Norambuena C, Silva G, Urbina A, Figueroa I, Rodríguez-Maciel JC. Insecticidal activity of Laureliopsis philippiana (Looser) Schodde (Atherospermataceae) essential oil against Sitophilus spp. (Coleoptera Curculionidae). Chilean J Agric Res 2016;76:330–6.10.4067/S0718-58392016000300010Suche in Google Scholar

47. Aref SP, Valizadegan O, Farashiani ME. The insecticidal effect of essential oil of Eucalyptus floribunda against two major stored product insect pests; Rhyzopertha dominica (F.) and Oryzaephilus surinamensis (L.). J Essent Oil Bear Pl 2016;19:820–31.10.1080/0972060X.2014.958569Suche in Google Scholar

48. Li XY, Chen XB, Liu QZ, Liu ZL. Chemical composition and insecticidal properties of the essential oil of Bidens frondosa L (Asteraceae) against booklice (Liposcelis bostrychophila). Trop J Pharm Res 2017;16:171–7.10.4314/tjpr.v16i1.23Suche in Google Scholar

49. Mendes LA, Martins GF, Valbon WR, da Silva de Souza T, Menini L, Ferreira A, et al. Larvicidal effect of essential oils from Brazilian cultivars of guava on Aedes aegypti L. Ind Crop Prod 2017;108:684–9.10.1016/j.indcrop.2017.07.034Suche in Google Scholar

50. Oboh G, Ademosun AO, Olumuyiwa TA, Olasehinde TA, Ademiluyi AO, Adeyemo AC. Insecticidal activity of essential oil from orange peels (Citrus sinensis) against Tribolium confusum, Callosobruchus maculatus and Sitophilus oryzae and its inhibitory effects on acetylcholinesterase and Na+/K+-ATPase activities. Phytoparasitica 2017;45:501–8.10.1007/s12600-017-0620-zSuche in Google Scholar

51. Wu Y, Guo SS, Huang DY, Wang CF, Wei JY, Li ZH, et al. Contact and repellant activities of zerumbone and its analogues from the essential oil of Zingiber zerumbet (L.) Smith against Lasioderma serricorne. J Oleo Sci 2017;66:399–405.10.5650/jos.ess16166Suche in Google Scholar PubMed

52. Saad KA, Roff MN, Idris AB. Toxic, repellent, and deterrent effects of Citronella essential oil on Bemisia tabaci (Hemiptera: Aleyrodidae) on Chili plants. J Entomol Sci 2017;52:119–30.10.18474/JES16-32.1Suche in Google Scholar

53. Guerreiro AC, Cecati FM, Ardanáz CE, Donadel OJ, Tonn CE, Sosa ME. Assessment of the insecticidal potential of the Eupatorium buniifolium essential oil against Triatoma infestans (Hemiptera: Reduviidae). A chiral recognition approach. Neotrop Entomol 2018;47:418–28.10.1007/s13744-018-0601-zSuche in Google Scholar PubMed

54. Wangrawa DW, Badolo A, Ilboudo Z, Guelbéogo WM, Kiendrébeogo M, Nébié RC, et al. Insecticidal activity of local plants essential oils against laboratory and field strains of Anopheles gambiae s. l. (Diptera: Culicidae) from Burkina Faso. J Econ Entomol 2018;111:2844–53.10.1093/jee/toy276Suche in Google Scholar PubMed

55. Navarro-Rocha J, Barrero AF, Burillo J, Olmeda AS, González-Coloma A. Valorization of essential oils from two populations (wild and commercial) of Geranium macrorrhizum L. Ind Crop Prod 2018;116:41–5.10.1016/j.indcrop.2018.02.046Suche in Google Scholar

56. Cao JQ, Guo SS, Wang Y, Pang X, Geng ZF, Du SS. Contact toxicity and repellency of the essential oils of Evodia lenticellata Huang and Evodia rutaecarpa (Juss.) Benth. leaves against three stored product insects. J Oleo Sci 2018;67:1027–34.10.5650/jos.ess17251Suche in Google Scholar PubMed

57. Chen ZY, Guo SS, Cao JQ, Pang X, Geng ZF, Wang Y, et al. Insecticidal and repellent activity of essential oil from Amomum villosum Lour. and its main compounds against two stored-product insects. Int J Food Prop 2018;21:2265–75.10.1080/10942912.2018.1508158Suche in Google Scholar

58. Hannour K, Boughdad A, Maataoui A, Bouchelta A. Chemical composition of Rosmarinus officinalis (Lamiaceae) essential oils and evaluation of their toxicity against Bruchus rufimanus (Coleoptera: Chrysomelidae: Bruchinae) in Morocco. Int J Trop Insect Sci 2018;38:192–204.10.1017/S1742758418000012Suche in Google Scholar

59. Tandon S, Mittal AK. Insecticidal and growth inhibitory activity of essential oils of Boenninghausenia albiflora and Teucrium quadrifarium against Spilarctia obliqua. Biochem Syst Ecol 2018;81:70–3.10.1016/j.bse.2018.09.010Suche in Google Scholar

60. Pavela R, Benelli G, Pavoni L, Bonacucina G, Cespi M, Cianfaglione K, et al. Microemulsions for delivery of Apiaceae essential oils – towards highly effective and eco-friendly mosquito larvicides? Ind Crop Prod 2019;129:631–40.10.1016/j.indcrop.2018.11.073Suche in Google Scholar

61. Satyal P, Hieu HV, Chuong NT, Hung NH, Sinh LH, The PV, et al. Chemical composition, Aedes mosquito larvicidal activity, and repellent activity against Triatoma rubrofasciata of Severinia monophylla leaf essential oil. Parasitol Res 2019;118:733–42.10.1007/s00436-019-06212-1Suche in Google Scholar PubMed

62. Huang HT, Lin CC, Kuo TC, Chen SJ, Huang RN. Phytochemical composition and larvicidal activity of essential oils from herbal plants. Planta 2019;250:59–68.10.1007/s00425-019-03147-wSuche in Google Scholar PubMed

63. Scalvenzi L, Radice M, Toma L, Severini F, Boccolini D, Bella A, et al. Larvicidal activity of Ocimum campechianum, Ocotea quixos and Piper aduncum essential oils against Aedes aegypti. Parasite 2019;26:23.10.1051/parasite/2019024Suche in Google Scholar PubMed PubMed Central

64. Tietbohl LA, Mello CB, Silva LR, Dolabella IB, Franco TC, Enríquez JJ, et al. Green insecticide against Chagas disease: effects of essential oil from Myrciaria floribunda (Myrtaceae) on the development of Rhodnius prolixus nymphs. J Essent Oil Res 2019; in press. DOI: 10.1080/10412905.2019.1631894.Suche in Google Scholar

65. Rehman JU, Wang M, Yang Y, Liu Y, Li B, Qin Y, et al. Toxicity of Kadsura coccinea (Lem.) A. C. Sm. essential oil to the bed bug, Cimex lectularius L. (Hemiptera: Cimicidae). Insects 2019;10:162.10.3390/insects10060162Suche in Google Scholar PubMed PubMed Central

66. Shao H, Wei C, Zhou S, Li W, Jiang C, Yang W, et al. Chemical composition and allelopathic, phytotoxic and pesticidal activities of Atriplex cana Ledeb. (Amaranthaceae) essential oil. Chem Biodivers 2019;16:e1800595.10.1002/cbdv.201800595Suche in Google Scholar PubMed

67. Mudrončeková S, Ferenčík J, Gruová D, Barta M. Insecticidal and repellent efects of plant essential oils against Ips typographus. J Pest Sci 2019;92:595–608.10.1007/s10340-018-1038-1Suche in Google Scholar

68. Maazoun AM, Hamdi SH, Belhadj F, Jemâ JM, Messaoud C, Marzouki MN. Phytochemical profile and insecticidal activity of Agave americana leaf extract towards Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Environ Sci Pollut Res 2019;26:19468–80.10.1007/s11356-019-05316-6Suche in Google Scholar PubMed

69. Feng YX, Wang Y, Chen ZY, Guo SS, You CX, Du SS. Efficacy of bornyl acetate and camphene from Valeriana officinalis essential oil against two storage insects. Environ Sci Pollut Res 2019;26:16157–65.10.1007/s11356-019-05035-ySuche in Google Scholar PubMed

70. Cao JQ, Pang X, Guo SS, Wang Y, Geng ZF, Sang YL, et al. Pinene-rich essential oils from Haplophyllum dauricum (L.) G. Don display anti-insect activity on two stored-product insects. Int Biodeter Biodegrad 2019;140:1–8.10.1016/j.ibiod.2019.03.007Suche in Google Scholar

71. Plata-Rueda A, Martínez LC, Dos Santos MH, Fernandes FL, Wilcken CF, Soares MA, et al. Insecticidal activity of garlic essential oil and their constituents against the mealworm beetle, Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae). Sci Rep 2017;7:46406.10.1038/srep46406Suche in Google Scholar PubMed PubMed Central

72. Mohanty SS, Jena HM. A systemic assessment of the environmental impacts and remediation strategies for chloroacetanilide herbicides. J Water Process Eng 2019;31:100860.10.1016/j.jwpe.2019.100860Suche in Google Scholar

73. Islam F, Wang J, Farooq MA, Khan MS, Xu L, Zhu J, et al. Potential impact of the herbicide 2,4-dichlorophenoxyacetic acid on human and ecosystems. Environ Int 2018;111:32–51.10.1016/j.envint.2017.10.020Suche in Google Scholar PubMed

74. Li Y, Sun Z, Zhuang X, Xu L, Chen S, Li M. Research progress on microbial herbicides. Crop Prot 2003;22:247–52.10.1016/S0261-2194(02)00189-8Suche in Google Scholar

75. M’barek K, Zribi I, Ullah MJ, Haouala R. The mode of action of allelochemicals aqueous leaf extracts of some Cupressaceae species on lettuce. Sci Hortic 2019;252:29–37.10.1016/j.scienta.2019.03.009Suche in Google Scholar

76. Khare P, Srivastava S, Nigam N, Singh AK, Singh S. Impact of essential oils of E. citriodora, O. basilicum and M. arvensis on three different weeds and soil microbial activities. Environ Technol Inno 2019;14:100343.10.1016/j.eti.2019.100343Suche in Google Scholar

77. Blázquez MA, Carbó E. Control of Portulaca oleracea by boldo and lemon essential oils in different soils. Ind Crop Prod 2015;76:515–21.10.1016/j.indcrop.2015.07.019Suche in Google Scholar

78. Fouad R, Bousta D, Lalami AE, Fouad OC, Amri I, Jamoussi B, et al. Chemical composition and herbicidal effects of essential oils of Cymbopogon citratus (DC) Stapf, Eucalyptus cladocalyx, Origanum vulgare L and Artemisia absinthium L. cultivated in Morocco. J Essent Oil Bear Pl 2015;18:112–23.10.1080/0972060X.2014.901631Suche in Google Scholar

79. Mahdavikia F, Saharkhiz MJ. Phytotoxic activity of essential oil and water extract of peppermint (Mentha×piperita L. CV. Mitcham). J Appl Res Med Aromat Plants 2015;2:146–53.10.1016/j.jarmap.2015.09.003Suche in Google Scholar

80. Ali IB, Chaouachi M, Bahri R, Chaieb I, Boussaïd M, Harzallah-Skhiri F. Chemical composition and antioxidant, antibacterial, allelopathic and insecticidal activities of essential oil of Thymus algeriensis Boiss. et Reut. Ind Crop Prod 2015;77:631–9.10.1016/j.indcrop.2015.09.046Suche in Google Scholar

81. El-Gawad AM. Chemical constituents, antioxidant and potential allelopathic effect of the essential oil from the aerial parts of Cullen plicata. Ind Crop Prod 2016;80:36–41.10.1016/j.indcrop.2015.10.054Suche in Google Scholar

82. Atak M, Mavi K, Uremis I. Bio-herbicidal effects of oregano and rosemary essential oils on germination and seedling growth of bread wheat cultivars and weeds. Rom Biotechnol Lett 2016;21:11149–59.Suche in Google Scholar

83. Ghnaya AB, Amri I, Hanana M, Gargouri S, Jamoussi B, Romane A, et al. Tetraclinis articulata (Vahl.) Masters essential oil from Tunisia: chemical characterization and herbicidal and antifungal activities assessment. Ind Crop Prod 2016;83:113–7.10.1016/j.indcrop.2015.12.026Suche in Google Scholar

84. Kordali S, Usanmaz A, Cakir A, Komaki A, Ercisli S. Antifungal and herbicidal effects of fruit essential oils of four Myrtus communis genotypes. Chem Biodivers 2016;13:77–84.10.1002/cbdv.201500018Suche in Google Scholar PubMed

85. Almarie AA, Mamat AS, Wahab Z, Rukunudin IH. Chemical composition and phytotoxicity of essential oils isolated from Malaysian plants. Allelopathy J 2016;37:55–70.Suche in Google Scholar

86. Benvenuti S, Cioni PL, Flamini G, Pardossi A. Weeds for weed control: Asteraceae essential oils as natural herbicides. Weed Res 2017;57:342–53.10.1111/wre.12266Suche in Google Scholar

87. Bozok F, Cenet M, Sezer G, Ulukanli Z. Essential oil and bioherbicidal potential of the aerial parts of Nepeta nuda subsp. albiflora (Lamiaceae). J Essent Oil Bear Pl 2017;20:148–54.10.1080/0972060X.2016.1264279Suche in Google Scholar

88. Fagodia SK, Singh HP, Batish DR, Kohli RK. Phytotoxicity and cytotoxicity of Citrus aurantiifolia essential oil and its major constituents: limonene and citral. Ind Crop Prod 2017;108:708–15.10.1016/j.indcrop.2017.07.005Suche in Google Scholar

89. Hazrati H, Saharkhiz MJ, Niakousari M, Moein M. Natural herbicide activity of Satureja hortensis L. essential oil nanoemulsion on the seed germination and morphophysiological features of two important weed species. Ecotoxicol Environ Saf 2017;142:423–30.10.1016/j.ecoenv.2017.04.041Suche in Google Scholar PubMed

90. Laosinwattana C, Wichittrakarn P, Teerarak M. Chemical composition and herbicidal action of essential oil from Tagetes erecta L. leaves. Ind Crop Prod 2018;126:129–34.10.1016/j.indcrop.2018.10.013Suche in Google Scholar

91. Üstüner T, Kordali S, Bozhüyük AU. Herbicidal and fungicidal effects of Cuminum cyminum, Mentha longifolia and Allium sativum essential oils on some weeds and fungi. Rec Nat Prod 2018;12:619–29.10.25135/rnp.80.18.05.106Suche in Google Scholar

92. Kaab SB, Rebey IB, Hanafi M, Berhal C, Fauconnier ML, De Clerck C, et al. Rosmarinus officinalis essential oil as an effective antifungal and herbicidal agent. Spanish J Agricult Res 2019;17:e1006.10.5424/sjar/2019172-14043Suche in Google Scholar

93. Sharma A, Singh HP, Batish DR, Kohli RK. Chemical profiling, cytotoxicity and phytotoxicity of foliar volatiles of Hyptis suaveolens. Ecotoxicol Environ Safe 2019;171:863–70.10.1016/j.ecoenv.2018.12.091Suche in Google Scholar PubMed

94. Carvalho MM, Oliveira EE, Matioli AL, Ferreira CL, da Silva NM, De Dea Lindner J. Stored products mites in cheese ripening: health aspects, technological and regulatory challenges in Brazil. J Stored Prod Res 2018;76:116–21.10.1016/j.jspr.2018.01.010Suche in Google Scholar

95. Fischer K, Walton S. Parasitic mites of medical and veterinary importance – is there a common research agenda? Int J Parasitol 2014;44:955–67.10.1016/j.ijpara.2014.08.003Suche in Google Scholar PubMed

96. Rizzoli A, Tagliapietra V, Cagnacci F, Marini G, Arnoldi D, Rosso F, et al. Parasites and wildlife in a changing world: the vector-host-pathogen interaction as a learning case. Int J Parasitol Par 2019;9:394–401.10.1016/j.ijppaw.2019.05.011Suche in Google Scholar PubMed PubMed Central

97. Adenubi OT, Fasina FO, McGaw LJ, Eloff JN, Naidoo V. Plant extracts to control ticks of veterinary and medical importance: a review. S Afr J Bot 2016;105:178–93.10.1016/j.sajb.2016.03.010Suche in Google Scholar

98. Rosado-Aguilar JA, Arjona-Cambranes K, Torres-Acosta JF, Rodríguez-Vivas RI, Bolio-González ME, Ortega-Pacheco A, et al. Plant products and secondary metabolites with acaricide activity against ticks. Vet Parasitol 2017;238:66–76.10.1016/j.vetpar.2017.03.023Suche in Google Scholar PubMed

99. Adenubi OT, Ahmed AS, Fasina FO, McGaw LJ, Eloff JN, Naidoo V. Pesticidal plants as a possible alternative to synthetic acaricides in tick control: a systematic review and meta-analysis. Ind Crop Prod 2018;123:779–806.10.1016/j.indcrop.2018.06.075Suche in Google Scholar

100. Fourie H, Ahuja P, Lammers J, Daneel M. Brassicacea-based management strategies as an alternative to combat nematode pests: a synopsis. Crop Prot 2016;80:21–41.10.1016/j.cropro.2015.10.026Suche in Google Scholar

101. Otranto D, Deplazes P. Zoonotic nematodes of wild carnivores. Int J Parasitol Par 2019;9:370–83.10.1016/j.ijppaw.2018.12.011Suche in Google Scholar PubMed PubMed Central

102. Zandi-Sohani N, Ramezani L. Evaluation of five essential oils as botanical acaricides against the strawberry spider mite Tetranychus turkestani Ugarov and Nikolskii. Int Biodeter Biodegrad 2015;98:101–6.10.1016/j.ibiod.2014.12.007Suche in Google Scholar

103. Hüe T, Cauquil L, Hzounda Fokou JB, Jazet Dongmo PM, Bakarnga-Via I, Menut C. Acaricidal activity of five essential oils of Ocimum species on Rhipicephalus (Boophilus) microplus larvae. Parasitol Res 2015;114:91–9.10.1007/s00436-014-4164-6Suche in Google Scholar PubMed

104. Costa-Júnior LM, Miller RJ, Alves PB, Blank AF, Li AY, Pérez de León AA. Acaricidal efficacies of Lippia gracilis essential oil and its phytochemicals against organophosphate-resistant and susceptible strains of Rhipicephalus (Boophilus) microplus. Vet Parasitol 2016;228:60–4.10.1016/j.vetpar.2016.05.028Suche in Google Scholar PubMed

105. Monteiro IN, Monteiro OD, Costa-Junior LM, da Silva Lima A, Andrade EH, Maia JG, et al. Chemical composition and acaricide activity of an essential oil from a rare chemotype of Cinnamomum verum Presl on Rhipicephalus microplus (Acari: Ixodidae). Vet Parasitol 2017;238:54–7.10.1016/j.vetpar.2017.03.016Suche in Google Scholar PubMed

106. Vinturelle R, Mattos C, Meloni J, Nogueira J, Nunes MJ, Vaz IS Jr, et al. In vitro evaluation of essential oils derived from Piper nigrum (Piperaceae) and Citrus limonum (Rutaceae) against the tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae). Biochem Res Int 2017;2017:5342947.10.1155/2017/5342947Suche in Google Scholar PubMed PubMed Central

107. Jeon YJ, Lee SG, Lee HS. Acaricidal and insecticidal activities of essential oils of Cinnamomum zeylanicum barks cultivated from France and India against Dermatophagoides spp., Tyrophagus putrescentiae and Ricania sp. Appl Biol Chem 2017;60:259–64.10.1007/s13765-017-0276-xSuche in Google Scholar

108. Fatemikia S, Abbasipour H, Saeedizadeh A. Phytochemical and acaricidal study of the galbanum, Ferula gumosa Boiss. (Apiaceae) essential oil against Tetranychus urticae Koch (Tetranychidae). J Essent Oil Bear Pl 2017;20:185–95.10.1080/0972060X.2016.1257957Suche in Google Scholar

109. Born FS, da Camara CA, de Melo JP, de Moraes MM. Acaricidal property of the essential oil from Lippia gracilis against Tetranychus urticae and a natural enemy, Neoseiulus californicus, under greenhouse conditions. Exp Appl Acarol 2018;75:491–502.10.1007/s10493-018-0286-3Suche in Google Scholar PubMed

110. Mahmoud NF, Badawy ME, Marei AE, Abdelgaleil SA. Acaricidal and antiacetylcholinesterase activities of essential oils from six plants growing in Egypt. Int J Acarol 2019;45:245–51.10.1080/01647954.2019.1611919Suche in Google Scholar

111. Ribeiro NC, da Camara CA, Melo JP, de Moraes MM. Acaricidal properties of essential oils from agro-industrial waste products from citric fruit against Tetranychus urticae. J Appl Entomol 2019;143:731–43.10.1111/jen.12642Suche in Google Scholar

112. Rey-Valeirón C, Pérez K, Guzmán L, López-Vargas J, Valarezo E. Acaricidal effect of Schinus molle (Anacardiaceae) essential oil on unengorged larvae and engorged adult females of Rhipicephalus sanguineus (Acari: Ixodidae). Exp Appl Acarol 2018;76:399–411.10.1007/s10493-018-0303-6Suche in Google Scholar PubMed

113. Avato P, Laquale S, Argentieri MP, Lamiri A, Radicci V, D’Addabbo T. Nematicidal activity of essential oils from aromatic plants of Morocco. J Pest Sci 2017;90:711–22.10.1007/s10340-016-0805-0Suche in Google Scholar

114. Álvarez D, Botina J, Ortiz A, Botina L. Evaluación nematicida del aceite esencial de Tagetes zypaquirensis en el manejo del nematodo Meloidogyne spp. Rev Cienc Agr 2016;33:22–33.10.22267/rcia.163301.3Suche in Google Scholar

115. Barros AF, Campos VP, de Paula LL, Oliveira DF, de Silva FJ, Terra WC, et al. Nematicidal screening of essential oils and potent toxicity of Dysphania ambrosioides essential oil against Meloidogyne incognita in vitro and in vivo. J Phytopathol 2019;167:380–9.10.1111/jph.12803Suche in Google Scholar

116. El-Hadary MH, Chung G. Herbicides – a double edged sword. In: Price AJ, Kelton JA, editors. Herbicides – Current Research and Case Studies in Use. Rijeka: IntechOpen, 2013:621.Suche in Google Scholar

117. U.S. Department of Agriculture, Agricultural Research Service. 1992–2016. Dr. Duke’s Phytochemical and Ethnobotanical Databases. Home page, http://phytochem.nal.usda.gov/ http://dx.doi.org/10.15482/USDA.ADC/1239279. Accessed on October 28, 2019.Suche in Google Scholar

118. U.S. National Library of Medicine, TOXNET (TOXicology Data NETwork). Home page, https://toxnet.nlm.nih.gov/newtoxnet/index.html. Accessed on October 28, 2019.Suche in Google Scholar

119. Faria JM. Essential Oils as Anti-nematode Agents and Their Influence on In Vitro Nematode/Plant Co-cultures [PhD thesis]. Portugal: Universidade de Lisboa, 2015. https://pdfs.semanticscholar.org/3700/117e4723d16cb8b2911a6a76abbc7bcc55ad.pdf. Accessed on September 12, 2019.Suche in Google Scholar

120. Daviet L, Schalk M. Biotechnology in plant essential oil production: progress and perspective in metabolic engineering of the terpene pathway. Flavour Fragr J 2010;25:123–7.10.1002/ffj.1981Suche in Google Scholar

121. Lange BM, Mahmoud SS, Wildung MR, Turner GW, Davis EM, Lange I, et al. Improving peppermint essential oil yield and composition by metabolic engineering. Proc Natl Acad Sci U S A 2011;108:16944–9.10.1073/pnas.1111558108Suche in Google Scholar PubMed PubMed Central

122. Cardoso-Ugarte GA, Juárez-Becerra GP, Sosa-Morales ME, López-Malo A. Microwave-assisted extraction of essential oils from herbs. J Microw Power Electromagn Energy 2013;47:63–72.10.1080/08327823.2013.11689846Suche in Google Scholar PubMed

123. Chu LL, Kang XJ, Wang Y. Extraction of onion (Allium cepa) essential oil by polystyrene nanofibrous membranes. J Food Proc Eng 2017;40:e12318.10.1111/jfpe.12318Suche in Google Scholar

Received: 2019-08-26
Revised: 2019-10-29
Accepted: 2019-11-05
Published Online: 2019-11-30
Published in Print: 2020-07-28

©2019 Walter de Gruyter GmbH, Berlin/Boston