Development of N-arylamide insecticides to control populations of the green aphid, Myzus persicae

The green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphididae), is one of the most damaging insect pests in agriculture due to photosynthate removal and horizontal transmission of plant viruses during feeding. We tested newly synthesized N-arylamide compounds for their ability to induce rapid knockdown and acute mortality to M. persicae. Contact toxicity was assessed through leaf dip bioassays and data indicate GMR031 (C₉H₃Cl₂F₇N₂O) and GMR138 (C₁₀H₃Cl₂F₈NO) are highly toxic with 4-hour LC₅₀ values of 44.7 ng/ml [95% CI: 28.51–71.86; Hillslope: 0.94; r²: 0.87] and 54.1 ng/ml [95% CI: 29.44–100.5; Hillslope: 0.70; r²: 0.84], respectively. Next, we performed electrical penetration graph (EPG) recordings to test if GMR031 and GMR138 alters feeding behavior relevant to horizontal transmission of viruses. Foliar applications of GMR031 and GMR138 significantly (P < 0.01) increased the time to first probe and the time required for initialization of a potential drop. Furthermore, foliar applications of GMR031 and GMR138 significantly (P < 0.0001) reduced the percentage of aphids that continued to initiate a new probe with potential drops after 1hr. This change in feeding behavior is relevant to aphicide development because nonpersistent virus acquisition and transmission occur during these potential drops, which are aphids sampling cell contents. Thus, disruption of probing and initiation of potential drops suggests N-arylamides are candidates to disrupt nonpersistent virus transmission. To conclude, GMR031 and GMR138 are toxic at concentrations approaching commercialized aphicides and could add to the small number of established aphicides that induce acute lethality and alter feeding biology relevant to pathogen transmission.