Effects of the residual activity of foliar-applied insecticides on Asian citrus psyllid (Diaphorina citri) feeding behavior

Citrus greening disease, also known as ‘Huanglongbing’ (HLB), is caused by a phloem-limited bacterium that is transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama. Application of insecticides to reduce psyllid populations is one of the primary methods used for HLB management. However, the ability of these insecticides to disrupt the psyllid feeding behaviors associated with pathogen acquisition and inoculation has not been previously determined. In this research, Electrical Penetration Graph (EPG) technology was used to study the feeding behaviors of D. citri and correlate them with successful pathogen acquisition and inoculation on citrus plants treated with one of five different insecticides: chlorpyrifos (Lorsban 4E), fenpropathrin (Danitol 2.4EC), imidacloprid (Provado 1.6F), spinetoram (Delegate WG) and spirotetramat (Movento 240SC). Untreated sour orange plants were used as controls. To replicate field conditions, treated plants were weathered outdoors during summer for 1 day, 1, 2, 3, or 4 weeks, and psyllids were recorded on mature leaves. Non-sequential feeding parameters for each treatment were compared using ANOVA. Results will be presented in terms of efficacy of each insecticide tested to disrupt psyllid feeding behaviors hypothesized to be responsible for pathogen acquisition and inoculation.