Negative effects of insecticides on non-target organism can be reduced by using selective and less toxic insecticides. We assessed the effect of subsequent application of flonicamid and Beauveria bassiana GHA on pests and natural enemies in soybean fields by recording their density in 6-8 d interval. Flonicamid controlled Aphis glycines Matsumura in 6 day after spray (DAS). Nymphs of Riptortus pedestris (F.) were also reduced by 46 and 48% in 12 and 19 DAS, respectively. Application of B. bassiana reduced R. pedestris nymph 50% in 16 DAS whereas adult R. pedestris, Medythia nigrobilineata Motschulsky and A. glycines were not significantly reduced in treated fields. Ladybird beetles, syrphid flies, hymenopteran wasps, and parasitism rate of R. pedestris eggs were not different between the treatment and control. These results suggest that flonicamid and B. bassiana showed less negative effect on the natural enemies and effective against aphids and nymphs stage of R. pedestris.

The cotton aphid, Aphis gossypii Glover is an important sap-sucking pest of many pant, including cucumber and pepper. The objective of the present study was to determine the effects of sublethal concentrations of two insecticides (imidacloprid and flonicamid) and the action mechanisms on the feeding behavior of A. gossypii. The median lethal concentrations (LC50) of imidacloprid and flonicamid for adult A. gossypii were 2.01 and 1.92 ppm, respectively. The sublethal concentrations of imidacloprid were 0.22 ppm (LC10) and 0.82 ppm (LC30), and those of flonicamid were 0.094 ppm (LC10) and 0.56 ppm (LC30). The developmental period of A. gossypii nymphs at LC30 was 3.6 days for both insecticide which shorter than controls (4.2 days). Adult longevities at LC10 and LC30 of imidacloprid were 15.2 and 13.6 days, respectively. Adult longevity at LC10 and LC30 of flonicamid was 11.1 and 9.9 days, respectively. Control adult longevity was 15.5 days. Total fecundity was decreased at both sublethal concentration of two insecticides. Feeding behavior analysis using an electrical penetration graph showed that sublethal doses of imidacloprid and flonicamid had significant effects on the duration of phloem ingestion. However, higher doses of flonicamid induced starvation by inhibition of phloem ingestion and higher doses of imidacloprid induced contact toxicity rather than inhibition of feeding behavior.

This study was performed to investigate the effect of flonicamid and thiamethoxam treated at sublethal concentration (LC10, LC30) on development period, adult longevity and fecundity and the feeding behaviour of Myzus persicae adult. Developmental period of M. Persicae nymph took 5.9 days in LC10, and 6.1 days in LC30 in both insecticides, comparing with control (5.7 days), it showed longer than those of the control, but there was no significance. Adult longevity treated at LC10 and LC30 of flonicamid was showed 13.2 and 13.7 days, respectively, and LC10 of thiamethoxam was examined as 14.7 days, it showed longer than control of 11.6 days. Mean daily fecundity exhibited higher in LC10 (3.1) and LC30 (3.1) of flonicamid than that of control (2.5), but thiamethoxam are not. Total fecundity exhibited higher in LC10 (41.8) and LC30 (43.0) of flonicamid, in LC10 (42.1) of thiamethoxam than that of control (29.5). Feeding behavior was examined using EPG (electrical penetration graph). EPG data indicated that flonicamid and thiamethoxam increased the duration of non-probing periods and decreased the duration of phloem ingestion.