Pascal M Ayelo1,2, Abdullahi A Yusuf2, Christian W W Pirk2, Anaïs Chailleux3,4, Samira A Mohamed1, Emilie Deletre1,3. 1. International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya. 2. Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa. 3. UPR HORTSYS, University of Montpellier, CIRAD, Montpellier, France. 4. 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.
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 5-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 4-component blend, suggesting synergism among four monoterpenes. CONCLUSION: These findings suggest that a 4-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. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
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 5-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 4-component blend, suggesting synergism among four monoterpenes. CONCLUSION: These findings suggest that a 4-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. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.