Effects of Diamide Insecticides on Predators in Soybean

Abstract

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.

Assessing Field‐Scale Risks of Foliar Insecticide Applications to Monarch Butterfly (Danaus plexippus) Larvae

“…The true armyworm is an example of a reemerging early‐season pest that is associated with the increased use of cover crops (Dunbar et al 2016). Although pyrethroids and organophosphates are the most commonly used foliar insecticides in soybean fields, neonicotinoids and diamides also are being used (Hodgson et al 2012; Whalen et al 2016). Potential risk of foliar insecticide applications to monarch larvae is a function of insecticide toxicity and exposure.…”

Monarch Butterfly (Danaus plexippus) Life‐Stage Risks from Foliar and Seed‐Treatment Insecticides

“…Pyrethroids and organophosphates are the most commonly used foliar insecticides; >190 000 kg were applied in Iowa in 2018 (US Department of Agriculture 2019). Neonicotinoids and diamides are also registered for foliar applications, though they are not as widely employed (Hodgson et al 2012; Whalen et al 2016). Less than a third of maize and soybeans in the north central United States are annually treated with foliar insecticides (US Department of Agriculture 2018); however, aerial applications, particularly of chlorantraniliprole, beta‐cyfluthrin, and chlorpyrifos, can result in high rates of downwind mortality.…”

Sublethal Effects of Diamide Insecticides on Development and Flight Performance of Chloridea virescens (Lepidoptera: Noctuidae): Implications for Bt Soybean Refuge Area Management

“…Several additional factors need to be considered in determining whether and to what degree these sublethal effects will disrupt resistance management. For example, diamides insecticides have been shown to have low toxicity to natural enemies [18,61]. Thus, target pests in refuge crops could be subject to higher levels of predation and parasitism from conserved natural enemies.…”