Testing the effect of commercialized aphicides on the feeding behavior of the cotton aphid, Aphis gossypii

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is one of the most destructive agricultural pests, due to both photosynthate removal and plant virus transmission. Horizontal transmission of plant viruses by aphids occurs during distinct feeding behavioral events, such as probing for non-persistent viruses or phloem feeding for persistent viruses. Thus, we employed electrical penetration graph (EPG) methodology to test the influence of commercialized aphicides on the feeding behavior of individual apterous cotton aphids. Products containing spirotetratmat, flonicamid, thiamethoxam, flupyradifurone, bifenthrin, sulfoxaflor, and pymetrozine applied to cotton significantly (P < 0.05) decreased the time to first probe with potential drops when compared to the untreated control. Conversely the total duration the aphids spent probing on cotton with potential drops was significantly (P < 0.001) reduced for products flonicamid, thiamethoxam, flupyradifurone, bifenthrin, sulfoxaflor, and thiamethoxam + lambda cyhalothrin. Interestingly, flupyradifurone was the only product that significantly reduced the proportion of aphids that probed on the cotton plant (38.5%) when compared to the control (69.2%). Further, E1 (phloem salivation) and E2 (phloem ingestion) waveforms were significantly (P < 0.05) reduced for products thiamethoxam, sulfoxaflor, thiamethoxam + lambda cyhalothrin, flupyradifurone, and flonicamid. We observed significant (P < 0.05) reduction of G phase (xylem ingestion) duration with flonicamid, thiamethoxam, flupyradifurone, bifenthrin, sulfoxaflor, thiamethoxam + lambda cyhalothrin, and pymetrozine. These data provide a baseline measure for the development of novel aphicides capable of inhibiting acquisition and transmission of plant viruses.