Journal Article

Insecticide sprays, natural enemy assemblages and predation on Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae)

Monzo, C., Qureshi, J.A., Stansly, P.A.

2014

Overview

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of ‘huanglongbing’ (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests.

• Publisher: Cambridge University Press
• Subject: adverse effects / Agricultural ecosystems / Agricultural management / agroecosystems / Animal populations / Animal, plant and microbial ecology / Animals / Applied ecology / Araneae / Arthropoda / Bacterial diseases / beneficial arthropods / Biological and medical sciences / Biological control / Citrus / Citrus fruits / Control / Diaphorina citri / Ecotoxicology, biological effects of pollution / Effects of pollution and side effects of pesticides on protozoa and invertebrates / fauna / Formicidae / Fruits / Fundamental and applied biological sciences. Psychology / greening disease / Hemiptera / immatures / Insect Control - methods / Insecticides / Insecticides - adverse effects / Insects / Invasive insects / Kuwayama / mortality / natural enemies / orchards / Pest control / Pest Control, Biological / Pests / Phytopathology. Animal pests. Plant and forest protection / Plant diseases / predation / Predatory Behavior - drug effects / Protozoa. Invertebrates / Psyllidae / Research Paper / Spiders - drug effects / Spiders - physiology / Sprays / spring / trees / vector control / winter