Biological effects and field persistence of different insecticides in controlling the cotton mealybug, Phenacoccus solenopsis (Tinsley) (Hemiptera: Pseudococcidae)

Cotton mealybug, Phenacoccus solenopsis (Tinsley), is an invasive pest threatening cotton crop. The efficacy and persistence of spirotetramat, sulfoxaflor, flonicamid, and buprofezin against the second-instar nymphs of P. solenopsis were evaluated under laboratory and greenhouse conditions. So far, there is no detailed information available on the sublethal effects of tested insecticides on the biological parameters of P. solenopsis, and thus, these effects at LC25 concentrations were assessed. In laboratory assays, sulfoxaflor was the most toxic, followed by spirotetramat and flonicamid; also, buprofezin was the least toxic on P. solenopsis nymphs after 48 h of exposure. Tested insecticides prolonged the developmental durations of treated nymphs and adult longevity for both sexes but significantly reduced female fecundity. Sulfoxaflor was the most persistent on cotton plants, whereas flonicamid was the lowest. Our findings indicated that tested insecticides could be regarded as promising candidates for establishing an effective control strategy to face P. solenopsis.