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Dady ER, Kleczewski N, Ugarte CM, Ngumbi E. Plant Variety, Mycorrhization, and Herbivory Influence Induced Volatile Emissions and Plant Growth Characteristics in Tomato. J Chem Ecol 2023; 49:710-724. [PMID: 37924424 DOI: 10.1007/s10886-023-01455-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 09/06/2023] [Accepted: 09/13/2023] [Indexed: 11/06/2023]
Abstract
Plants produce a range of volatile organic compounds (VOCs) that mediate vital ecological interactions between herbivorous insects, their natural enemies, plants, and soil dwelling organisms including arbuscular mycorrhizal fungi (AMF). The composition, quantity, and quality of the emitted VOCs can vary and is influenced by numerous factors such as plant species, variety (cultivar), plant developmental stage, root colonization by soil microbes, as well as the insect developmental stage, and level of specialization of the attacking herbivore. Understanding factors shaping VOC emissions is important and can be leveraged to enhance plant health and pest resistance. In this greenhouse study, we evaluated the influence of plant variety, mycorrhizal colonization, herbivory, and their interactions on the composition of emitted volatiles in tomato plants (Solanum lycopersicum L.). Four tomato varieties from two breeding histories (two heirlooms and two hybrids), were used. Tomato plants were inoculated with a commercial inoculum blend consisting of four species of AMF. Plants were also subjected to herbivory by Manduca sexta (Lepidoptera: Sphingidae L.) five weeks after transplanting. Headspace volatiles were collected from inoculated and non-inoculated plants with and without herbivores using solid phase-microextraction. Volatile profiles consisted of 21 different volatiles in detectable quantities. These included monoterpenes, sesquiterpenes, and alkane hydrocarbons. We documented a strong plant variety effect on VOC emissions. AMF colonization and herbivory suppressed VOC emissions. Plant biomass was improved by colonization of AMF. Our results show that mycorrhization, herbivory and plant variety can alter tomato plant VOC emissions and further shape volatile-mediated insect and plant interactions.
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Affiliation(s)
- Erinn R Dady
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | | | - Carmen M Ugarte
- Department of Natural Resources and Environmental Sciences, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Esther Ngumbi
- Department of Entomology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
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Rodrigo F, Burgueño AP, González A, Rossini C. Better Together: Volatile-Mediated Intraguild Effects on the Preference of Tuta absoluta and Trialeurodes vaporariorum for Tomato Plants. J Chem Ecol 2023; 49:725-741. [PMID: 37924423 DOI: 10.1007/s10886-023-01458-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/29/2023] [Accepted: 10/05/2023] [Indexed: 11/06/2023]
Abstract
Plant-herbivore interactions have been extensively studied in tomato plants and their most common pests. Tomato plant chemical defenses, both constitutive and inducible, play a role in mediating these interactions. Damaged tomato plants alter their volatile profiles, affecting herbivore preferences between undamaged and damaged plants. However, previous studies on tomato volatiles and herbivore preferences have yielded conflicting results, both in the volatile chemistry itself as well as in the attraction/repellent herbivore response. This study revisits the volatile-mediated interactions between tomato plants and two of their main herbivores: the leafminer Tuta absoluta and the whitefly Trialeurodes vaporariorum. Tomato plant volatiles were analyzed before and after damage by each of these herbivores, and the preference for oviposition (T. absoluta) and settling (T. vaporariorum) on undamaged and damaged plants was assessed both after conspecific and heterospecific damage. We found that both insects consistently preferred damaged plants over undamaged plants. The emission of herbivore-induced plant volatiles (HIPVs) increased after T. absoluta damage but decreased after T. vaporariorum damage. While some of our findings are in line with previous reports, T. absoluta preferred to oviposit on plants damaged by conspecifics, which differs from earlier studies. A comparison of HIPVs emitted after damage by T. absoluta and T. vaporariorum revealed differences in up- or down-regulation, as well as significant variations in specific compounds (12 for T. absoluta and 26 for T. vaporariorum damaged-plants). Only two compounds, β-caryophyllene and tetradecane, significantly varied because of damage by either herbivore, in line with the overall variation of the HIPV blend. Differences in HIPVs and herbivore preferences may be attributed to the distinct feeding habits of both herbivores, which activate different defensive pathways in plants. The plant's challenge in simultaneously activating both defensive pathways may explain the preference for heterospecific damaged plants found in this study, which are also in line with our own observations in greenhouses.
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Affiliation(s)
- F Rodrigo
- Laboratorio de Ecología Química, Facultad de Química, Universidad de la República, Gral. Flores 2124, Montevideo, CP 11800, Uruguay
- Graduate Program in Chemistry, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - A P Burgueño
- Laboratorio de Ecología Química, Facultad de Química, Universidad de la República, Gral. Flores 2124, Montevideo, CP 11800, Uruguay
- Graduate Program in Chemistry, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - A González
- Laboratorio de Ecología Química, Facultad de Química, Universidad de la República, Gral. Flores 2124, Montevideo, CP 11800, Uruguay
| | - C Rossini
- Laboratorio de Ecología Química, Facultad de Química, Universidad de la República, Gral. Flores 2124, Montevideo, CP 11800, Uruguay.
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Xiao D, Liu J, Liu Y, Wang Y, Zhan Y, Liu Y. Exogenous Application of a Plant Elicitor Induces Volatile Emission in Wheat and Enhances the Attraction of an Aphid Parasitoid Aphidius gifuensis. PLANTS (BASEL, SWITZERLAND) 2022; 11:3496. [PMID: 36559606 PMCID: PMC9785975 DOI: 10.3390/plants11243496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
It is well known that plant elicitors can induce plant defense against pests. The herbivore-induced plant volatile (HIPV) methyl salicylate (MeSA), as a signaling hormone involved in plant pathogen defense, is used to recruit natural enemies to protect wheat and other crops. However, the defense mechanism remains largely unknown. Here, the headspace volatiles of wheat plants were collected and analyzed by gas chromatography-mass spectrometry (GC-MS), gas chromatography with electroantennographic detection (GC-EAD) and principal component analysis (PCA). The results showed that exogenous application of MeSA induced qualitative and quantitative changes in the volatiles emitted from wheat plants, and these changes were mainly related to Carveol, Linalool, m-Diethyl-benzene, p-Cymene, Nonanal, D-limonene and 6-methyl-5-Hepten-2-one. Then, the electroantennogram (EAG) and Y-tube bioassay were performed to test the physiological and behavioral responses of Aphidius gifuensis Ashmesd to the active volatile compounds (p-Cymene, m-Diethyl-benzene, Carveol) that identified by using GC-EAD. The female A. gifuensis showed strong physiological responses to 1 μg/μL p-Cymene and 1 μg/μL m-Diethyl-benzene. Moreover, a mixture blend was more attractive to female A. gifuensis than a single compound. These findings suggested that MeSA could induce wheat plant indirect defense against wheat aphids through attracting parasitoid in the wheat agro-ecosystem.
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Affiliation(s)
- Dianzhao Xiao
- College of Plant Protection, Shandong Agricultural University, No. 61 Daizong Road, Taian 271018, China
| | - Jiahui Liu
- College of Plant Protection, Shandong Agricultural University, No. 61 Daizong Road, Taian 271018, China
- Department of Functional and Evolutionary Entomology, University of Liège, Gembloux Agro-Bio Tech, Passage des Déportés 2, 5030 Gembloux, Belgium
| | - Yulong Liu
- College of Plant Protection, Shandong Agricultural University, No. 61 Daizong Road, Taian 271018, China
| | - Yiwei Wang
- College of Plant Protection, Shandong Agricultural University, No. 61 Daizong Road, Taian 271018, China
| | - Yidi Zhan
- College of Plant Protection, Shandong Agricultural University, No. 61 Daizong Road, Taian 271018, China
| | - Yong Liu
- College of Plant Protection, Shandong Agricultural University, No. 61 Daizong Road, Taian 271018, China
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Song C, Ma L, Zhao J, Xue Z, Yan X, Hao C. Electrophysiological and Behavioral Responses of Plutella xylostella (Lepidoptera: Plutellidae) to Volatiles from a Non-host Plant, Geranium, Pelargonium × hortorum (Geraniaceae). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:5982-5992. [PMID: 35576618 DOI: 10.1021/acs.jafc.1c08165] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The diamondback moth (DBM), Plutella xylostella (Lepidoptera: Plutellidae), is a notorious cruciferous vegetable pest globally. Mechanically damaged geranium (Pelargonium × hortorum) can strongly repel DBM, but specific plant bioactive compounds responsible for such effects have not been identified. The headspace volatiles from wounded geranium were analyzed using gas chromatography-electroantennographic detection and gas chromatography-mass spectrometry. The electrophysiological and behavioral responses of DBM females to these chemicals and two blends were investigated. The results showed that five components myrcene, γ-terpinene, linalool, camphor, and terpinen-4-ol in geranium plants mediated the repellence of DBM mated females. These substances significantly repelled the oviposition of females, and blend-2 (a mixture of the five components with a ratio 1:5:3:4:3) was most effective. The slow-release blend-2 had a repellent range of 0.9 m and a repellent longevity of 26 days. These five substances are promising behavioral regulators of the destructive moths and could be potential candidates for "push" components in plant-based "push-pull" strategies.
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Affiliation(s)
- Chengfei Song
- College of Plant Protection, Shanxi Agricultural University, Taigu 030801, PR China
| | - Li Ma
- College of Plant Protection, Shanxi Agricultural University, Taigu 030801, PR China
| | - Jinyu Zhao
- College of Plant Protection, Shanxi Agricultural University, Taigu 030801, PR China
| | - Zengsheng Xue
- College of Plant Protection, Shanxi Agricultural University, Taigu 030801, PR China
| | - Xizhong Yan
- College of Plant Protection, Shanxi Agricultural University, Taigu 030801, PR China
| | - Chi Hao
- College of Plant Protection, Shanxi Agricultural University, Taigu 030801, PR China
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Agbessenou A, Akutse KS, Yusuf AA, Khamis FM. The Endophyte Trichoderma asperellum M2RT4 Induces the Systemic Release of Methyl Salicylate and ( Z)-jasmone in Tomato Plant Affecting Host Location and Herbivory of Tuta absoluta. FRONTIERS IN PLANT SCIENCE 2022; 13:860309. [PMID: 35449888 PMCID: PMC9016226 DOI: 10.3389/fpls.2022.860309] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 03/11/2022] [Indexed: 05/30/2023]
Abstract
The use of endophytic fungi has dramatically increased plant performance through the enhancement of plant protection against abiotic and biotic stressors. We previously demonstrated that the endophytic fungus Trichoderma asperellum M2RT4 improves tomato defenses against the tomato leafminer Tuta absoluta through the reduction of oviposition, leafmining, pupation, and adult emergence. However, the underlying mechanism by which the presence of this endophytic fungus within tomato host plant affects T. absoluta host selection and life-history traits is unknown. We tested the behavioral responses of T. absoluta in Y-tube olfactometer bioassays and found that females preferred non-inoculated tomato plants against those inoculated by endophytes. Additionally, T. absoluta females were not attracted to non-inoculated infested nor to inoculated-infested tomato plants. Chemical analysis revealed the emission of methyl salicylate in inoculated tomato plant and an increase in the amounts of monoterpenes emitted from non-inoculated infested plants. Additionally, we found that upon herbivory, T. asperellum M2RT4 modulates tomato plant chemistry through the production of (Z)-jasmone thus activating both salicylic and jasmonic acid defense pathways. Further, T. absoluta females were attracted to monoterpernes including α-pinene, 2-carene, and β-phellandrene but repelled by methyl salicylate. Methyl salicylate could therefore be considered as a good semiochemical-based candidate for sustainable T. absoluta management using a "push-pull" approach. However, in dose-response bioassays, females of T. absoluta did not show any preference to the four component-blend (α-pinene, 2-carene, β-phellandrene, and methyl salicylate). (Z)-jasmone-treated tomato leaflets significantly reduced the leafmining activity of the pest at the concentration of 10 ng/μL and causing the highest larval mortality rate (83%) with the shortest LT50 (1.73 days) 7 days post-treatment. T. asperellum M2RT4 effect on herbivore performance was then (Z)-jasmone-mediated. These findings expand our understanding of how the endophytic fungus T. asperellum M2RT4 could mediate chemical interactions between T. absoluta and its host plant which are potentially important for development of environmentally friendly T. absoluta management programs.
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Affiliation(s)
- Ayaovi Agbessenou
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Komivi S. Akutse
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Abdullahi A. Yusuf
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
- Forestry and Agricultural Biotechnology Institute, University of Pretoria, Hatfield, South Africa
| | - Fathiya M. Khamis
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
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Botanic Garden as a Factory of Molecules: Myrtus communis L. subsp. communis as a Case Study. PLANTS 2022; 11:plants11060754. [PMID: 35336637 PMCID: PMC8949965 DOI: 10.3390/plants11060754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 03/09/2022] [Accepted: 03/09/2022] [Indexed: 11/30/2022]
Abstract
A novel perception of botanic gardens as complex “factories of molecules” (Lombardy Region Project–Lr. 25/2016, year 2021), that mediate plant–environment interactions, and are the basis of their utility for humans, is presented. The core-topic is the medicinal plant heritage of the Ghirardi Botanic Garden (Toscolano Maderno, Brescia, Italy) of the University of Milan. In this work, we studied Myrtus communis L. subsp. communis (Myrtaceae) at multiple scale levels: macro- and micromorphological, with special emphasis on the secretory structures responsible for the production of secondary metabolites; phytochemical, with the analysis of the essential oil (EO) composition from leaves (fresh, dried, stored at −20 °C and at −80 °C) and fruits over two consecutive years (2018 and 2019); bio-ecological, with a focus, based on literature data, on the ecology and biological activity of the main EO components. The occurrence of secretory cavities producing terpenes, along with flavonoids, was proven. A high level of chemical variability across the obtained EO profiles emerged, especially that concerning quantitative data. However, regardless of the different conservation procedures, the examined plant part, or the phenological stage, we detected the presence of three ubiquitous compounds: α-pinene, 1,8-cineole, and linalool. The overall results will serve to enrich the Ghirardi Botanic Garden with novel labeling showing accurate and updated scientific information in an Open science perspective.
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Ayelo PM, Yusuf AA, Chailleux A, Mohamed SA, Pirk CWW, Deletre E. Chemical Cues From Honeydew and Cuticular Extracts of Trialeurodes Vaporariorum Serve as Kairomones for The Parasitoid Encarsia Formosa. J Chem Ecol 2022; 48:370-383. [PMID: 35257255 DOI: 10.1007/s10886-022-01354-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/14/2022] [Accepted: 02/17/2022] [Indexed: 11/25/2022]
Abstract
Kairomones are semiochemicals that are emitted by an organism and which mediate interspecific interaction that is of benefit to an organism of another species that receives these chemical substances. Parasitoids find and recognize their hosts through eavesdropping on the kairomones emitted from the by-products or the body of the host. Hemipteran insect pests feed on plant sap and excrete the digested plant materials as honeydew. Honeydew serves as a nutritional food source for parasitoids and a medium for micro-organisms whose activity induces the release of volatiles exploited by parasitoids for host location. The parasitoid Encarsia formosa preferentially parasitizes its host, the greenhouse whitefly, Trialeurodes vaporariorum, on tomato Solanum lycopersicum, but little is known about the chemicals that mediate these interactions. We investigated the olfactory responses of the parasitoid E. formosa to odours from honeydew and nymphs of T. vaporariorum in a Y-tube olfactometer. Arrestment behaviour of the parasitoid to honeydew and nymph extracts, as well as to synthetic hydrocarbons, was also observed in Petri-dish bioassays. We found that T. vaporariorum honeydew volatiles attracted the parasitoid E. formosa but odours from the whitefly nymphs did not. We also found that the parasitoid spent more time searching on areas treated with extracts of honeydew and nymphs than on untreated areas. Gas-chromatography-mass spectrometric analysis revealed that the honeydew volatiles contained compounds such as (Z)-3-hexenol, δ-3-carene, 3-octanone, α-phellandrene, methyl salicylate, β-ocimene, β-myrcene, and (E)-β-caryophyllene which are known to be attractive to E. formosa. The cuticular extracts of the nymphs predominantly contained alkanes, alkenes, and esters. Among the alkanes, synthetic nonacosane arrested the parasitoid. Our findings are discussed in relation to how the parasitoid E. formosa uses these chemicals to locate its host, T. vaporariorum.
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Affiliation(s)
- Pascal Mahukpe Ayelo
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.
- Social Insects Research Group, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa.
| | - Abdullahi A Yusuf
- Social Insects Research Group, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Anaïs Chailleux
- CIRAD-UPR HORTSYS, University of Montpellier, Montpellier, France
- Biopass2, Cirad-IRD-ISRA-UGB, Dakar, Senegal
| | - Samira A Mohamed
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Christian W W Pirk
- Social Insects Research Group, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Emilie Deletre
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.
- CIRAD-UPR HORTSYS, University of Montpellier, Montpellier, France.
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Mwamba S, Kihika-Opanda R, Murungi LK, Losenge T, Beck JJ, Torto B. Identification of Repellents from Four Non-Host Asteraceae Plants for the Root Knot Nematode, Meloidogyne incognita. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:15145-15156. [PMID: 34882384 DOI: 10.1021/acs.jafc.1c06500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Olfactory cues guide plant parasitic nematodes (PPNs) to their host plants. We tested the hypothesis that non-host plant root volatiles repel PPNs. To achieve this, we compared the olfactory responses of infective juveniles (J2s) of the PPN Meloidogyne incognita to four non-host Asteraceae plants, namely, black-jack (Bidens pilosa), pyrethrum (Chrysanthemum cinerariifolium), marigold (Tagetes minuta), and sweet wormwood (Artemisia annua), traditionally used in sub-Saharan Africa for the management of PPNs. Chemical analysis by coupled gas chromatography-mass spectrometry (GC/MS) combined with random forest analysis, followed by behavioral assays, identified the repellents in the root volatiles of B. pilosa, T. minuta, and A. annua as (E)-β-farnesene and 1,8-cineole, whereas camphor was attractive. In contrast, random forest analysis predicted repellents for C. cinerariifolium and A. annua as β-patchoulene and isopropyl hexadecanoate. Our results suggested that terpenoids generally account for the repellency of non-host Asteraceae plants used in PPN management.
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Affiliation(s)
- Sydney Mwamba
- Behavioural and Chemical Ecology Unit, International Centre of Insect Physiology and Ecology, P.O. Box 30772, Nairobi 00100, Kenya
- Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000, Nairobi 00200, Kenya
- Ministry of Agriculture, Seed Control and Certification Institute, P.O. Box 350199, Chilanga 00100, Zambia
| | - Ruth Kihika-Opanda
- Behavioural and Chemical Ecology Unit, International Centre of Insect Physiology and Ecology, P.O. Box 30772, Nairobi 00100, Kenya
| | - Lucy K Murungi
- Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000, Nairobi 00200, Kenya
| | - Turoop Losenge
- Department of Horticulture, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000, Nairobi 00200, Kenya
| | - John J Beck
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Agricultural Research Service, U.S. Department of Agriculture, 1700 SW 23rd Drive, Gainesville, Florida 32608, United States
| | - Baldwyn Torto
- Behavioural and Chemical Ecology Unit, International Centre of Insect Physiology and Ecology, P.O. Box 30772, Nairobi 00100, Kenya
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Ayelo PM, Yusuf AA, Pirk CW, Chailleux A, Mohamed SA, Deletre E. Terpenes from herbivore-induced tomato plant volatiles attract Nesidiocoris tenuis (Hemiptera: Miridae), a predator of major tomato pests. PEST MANAGEMENT SCIENCE 2021; 77:5255-5267. [PMID: 34310838 DOI: 10.1002/ps.6568] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/26/2021] [Indexed: 05/19/2023]
Abstract
BACKGROUND Biological control plays a key role in reducing crop damage by Tuta absoluta (Meyrick) and Trialeurodes vaporariorum (Westwood), which cause huge yield losses in tomato (Solanum lycopersicum L.). The mirid predator Nesidiocoris tenuis (Reuter) preys heavily on these pests, with satisfying control levels in tomato greenhouses. Although N. tenuis is known to be attracted to volatiles of tomato plants infested by T. absoluta and whitefly, little is known about the specific attractive compounds and the effect of prey density on the predator response. RESULTS Y-tube olfactometer bioassays revealed that the attraction of N. tenuis to tomato volatiles was positively correlated with the density of T. absoluta infestation, unlike T. vaporariorum infestation. The predator was also attracted to volatiles of T. absoluta larval frass, but not to T. vaporariorum honeydew or T. absoluta sex pheromone. Among the herbivore-induced plant volatiles (HIPVs) that characterised the attractive plants infested with 20 T. absoluta larvae, olfactometer bioassays revealed that N. tenuis is attracted to the monoterpenes α-pinene, α-phellandrene, 3-carene, β-phellandrene and β-ocimene, whereas (E)-β-caryophyllene was found to repel the predator. In dose-response bioassays, the five-component blend of the attractants elicited a relatively low attraction in the predator, and removal of β-phellandrene from the blend enhanced the attraction of the predator to the resulting four-component blend, suggesting synergism among four monoterpenes. CONCLUSION These findings suggest that a four-component blend of α-pinene, α-phellandrene, 3-carene and β-ocimene could be used as a kairomone-based lure to recruit the predator for the biological control of T. absoluta and T. vaporariorum.
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Affiliation(s)
- Pascal M Ayelo
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Abdullahi A Yusuf
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Christian Ww Pirk
- Department of Zoology and Entomology, University of Pretoria, Hatfield, South Africa
| | - Anaïs Chailleux
- UPR HORTSYS, University of Montpellier, CIRAD, Montpellier, France
- Biopass2, Cirad-IRD-ISRA-UGB - Centre de coopération internationale en recherche agronomique pour le développement, Institut de Recherche pour le Développement-Institut Sénégalais de Recherches Agricoles, Université Gaston Berger, Dakar, Senegal
| | - Samira A Mohamed
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Emilie Deletre
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- UPR HORTSYS, University of Montpellier, CIRAD, Montpellier, France
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