Effects of Diamide Insecticides on Predators in Soybean

Predatory arthropods can be important for preventing insect pests from reaching damaging levels in soybean. However, the predator community can be compromised when pest control strategies include the application of broad-spectrum insecticides. The use of selective insecticides such as diamides could conserve predators while still providing necessary pest control. We evaluated two selective diamide insecticides, chlorantraniliprole and flubendiamide, and a broad-spectrum insecticide, lambda-cyhalothrin in combination with chlorantraniliprole, for impact on predators in soybean. We applied insecticides to field plots and documented predator abundance prior to and up to 3 wk postapplication using sticky card, beat sheet, and sweep net sampling methods. In sweep net samples, total predator abundance in plots treated with the selective insecticides was not significantly different from untreated control plots. For beat sheet samples, there were no significant differences in the abundance of total predators on any day postapplication between the selective diamide insecticides or the untreated control, but abundance decreased after application of lambda-cyhalothrin + chlorantraniliprole and did not recover. For sticky cards, there were no differences in predator abundance among treatments on any day postapplication. Over all, results showed that there were no significant differences in the abundance of total predators, Anthocoridae, Araneae, or Geocoridae after application of flubendiamide or chlorantraniliprole compared with the untreated control for up to 3 wk after application. All insecticides significantly decreased populations of lepidopteran pests compared with the untreated control, but only lambda-cyhalothrin + chlorantraniliprole reduced predatory arthropod abundance.