Assessment of the effects of novel insecticides on green peach aphid (Myzus persicae) feeding and transmission of Turnip mosaic virus (TuMV)

BACKGROUND Laboratory bioassays using treated leaf disks of peach were conducted to determine the efficacy of nine insecticides against the green peach aphid (GPA), Myzus persicae (Sulzer). The effects of these insecticides on aphid feeding behaviors and rates of transmission of Turnip mosaic virus (TuMV) to potted rutabaga plants were also determined. RESULTS Median lethal concentration (LC50) values after 48 h feeding varied considerably, ranging from lows of 1.5 and 4.6 mu g a.i./L for sulfoxaflor and lambda-cyhalothrin, respectively, to 97.2 and 167.9 mu g a.i./L for flonicamid and spirotetramat. LC50 values were lowest and roughly equivalent for lambda-cyhalothrin (1.2) acetamiprid (2.1), sulfoxaflor (0.23) and flupyradifurone (2.3) after 72 h feeding. Electrical penetration graph (EPG) recordings showed modest effects on feeding behaviors for certain insecticides, with sulfoxaflor, spirotetramat, and acetamiprid non-significant reduction in feeding duration and number of pathway and potential drop phases occurring during the first 5 min compared with the control. However, greenhouse experiments carried out to investigate the effect of these insecticides on rates of transmission of TuMV, which is transmitted non-persistently by GPA, resulted in only modest non-significant reductions in infection rates for acetamiprid, pymetrozine, lambda-cyhalothrin, and flonicamid of 27%, 23%, 20%, and 17%, respectively. CONCLUSION All test materials were efficacious to GPA at differing levels, and some such as sulfoxaflor and acetamiprid non-significantly reduced the duration and number of pathways and potential drop phases of feeding within the first 5 min. None, however, resulted in significant reductions in rates of transmission of TuMV.

Automated summary

Laboratory bioassays were conducted to determine the efficacy of nine insecticides against the green peach aphid. While some insecticides showed modest effects on aphid feeding behaviors, none resulted in significant reductions in rates of transmission of Turnip mosaic virus.