Biological control of silverleaf whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) using predatory bugs, Dicyphus hesperus (Hemiptera: Miridae) and Orius insidiosus (Hemiptera: Anthocoridae)

Résumé En Fr

The silverleaf whitefly (SLW), Bemisia tabaci, is an exotic pest that causes sporadic crop damage in Canadian greenhouses, mainly on tomatoes. Its plant feeding is responsible for both direct damage as well as the transmission of plant viruses. Interestingly, omnivorous predators, which are used as biological control agents for multiple whitefly species, can establish on greenhouse crops even before the pest has established, using alternative food resources and host plants to support the predator. However, the efficiency of such indigenous omnivorous biological agents in the suppression of high density and intense SLW infestations remains unknown. This research aimed to assess the potential of two indigenous omnivorous biological agents, Dicyphus hesperus and Orius insidiosus to control SLW infestations and their effects on tomato plant health and yield at both early stages of the crop cycle, and at high pest densities. This study showed that populations of B. tabaci are able to grow rapidly. However, neither of the introduced densities of B. tabaci nor the infestation time had a significant effect on the incidence of tomato irregular ripening disorder (TIR) and yield. Our results also show that the introduction of three or five D. hesperus adults per cage reduces the number of B. tabaci larvae and pseudo-nymphs, while O. insidiosus did not significantly reduce SLW populations. Our results suggest that D. hesperus could control high levels of SWL and at an early stage in the cropping cycle.

L’aleurode du tabac (SLW), Bemisia tabaci, est un ravageur exotique qui cause des dommages sporadiques dans les serres canadiennes, principalement en culture de tomates. Son comportement alimentaire est responsable de dommages directs et de la transmission de virus. Les prédateurs omnivores peuvent s’établir en serre avant l’arrivée des ravageurs, en utilisant des proies et hôtes alternatifs. Toutefois, l’efficacité des prédateurs indigènes contre B. tabaci reste inconnue. Cette étude avait pour objectif de tester la réponse des plants de tomate aux infestations hâtives et de fortes intensités de B. tabaci, et le potentiel de deux punaises omnivores indigènes, Dicyphus hesperus et Orius insidiosus. Les résultats démontrent que les populations de B. tabaci augmentent rapidement. Cependant, ni la densité ni le temps d’infestation n’avaient d’effet significatif sur le trouble du désordre de maturation (TIR) et sur le rendement. L’introduction de trois et cinq D. hesperus adultes réduisait le nombre de larves et nymphes de B. tabaci, alors que l’utilisation d’O. insidiosus n’a pas permis de réduire significativement les populations. Nos résultats suggèrent que D. hesperus pourrait réguler de fortes et brèves infestations de B. tabaci.