Effects of clothianidin‐treated seed on the arthropod community in a mid‐Atlantic no‐till corn agroecosystem

Abstract

Clothianidin primarily influenced arthropod communities during the 4 weeks following planting, with disruptions to major natural enemy taxa, but communities showed trends toward recovery at the later corn stages. While the insecticide suppressed multiple herbivores, none were economically damaging to corn; thus, the pest suppression benefits of clothianidin observed in this study did not justify the non-target impacts. © 2018 Society of Chemical Industry.

Ecological impacts of pesticide seed treatments on arthropod communities in a grain crop rotation

“…Additionally, it has been suggested that individual studies of pesticide non-target impacts lack the power to detect effects due to relatively small sample size and high variability in arthropod community datasets (Douglas & Tooker, 2016). A meta-analysis across 20 studies revealed small negative effects [effect size d = −0.30 ± 0.10 (95% confidence interval)] on natural enemy abundance associated with NSTs, with a trend towards soil taxa being more impacted than foliar taxa (Douglas & Tooker, 2016 we expected foliar communities to recover rapidly, as observed by Disque et al (2018) in maize. In contrast, PRC analysis for sticky cards showed increasing deviations from the control community over time in insecticide-treated winter wheat and for all pesticide treatments in maize, with no recovery over the sampling period.…”

“…In foliar sweep net and visual samples from soybeans, we also observed reduced abundance or activity density of lady beetles (Coccinellidae), which are known to be impacted by neonicotinoids (Amjad, Azam, Sarwar, Malik, & Sattar, 2018;Disque et al, 2018;Zhang et al, 2016), as well as predatory thrips; some of these impacts occurred across all three pesticide treatments and thus may have been driven by the fungicide treatments. In contrast, spider abundance was higher in the maize visual samples from the insecticide-treated plots, and to a lesser extent the fungicide-treated plots.…”

“…Other studies have described variable NSTs impacts on soil taxa in maize and soybeans (Atwood, Mortensen, Koide, & Smith, 2018;Disque et al, 2018). Clothianidin-treated maize reduced the activity density of scelionid wasps, ants, carabid beetles and staphylinid beetles early in the season with effects diminishing over the course of the season in PRC analysis of pitfall data (Disque et al, 2018).…”

“…We anticipated the strongest impacts on the soil community, given the potential soil persistence of active ingredients and the short activity period in plant tissue. We expected community disturbance early on with recovery during each cropping cycle as observed previously in maize (Disque et al, 2018), but hypothesized that disturbance in the soil community would increase over the course of the study due to potential cumulative impacts of repeated NST use. We also hypothesized that the fungicide-only treatment could also impact the arthropod community, due to direct toxicity of seed-applied fungicides towards arthropods (Minnesota Department of Agriculture, 2012) or indirect alteration of crop fungal communities.…”

Evaluating the ecological impacts of pesticide seed treatments on arthropod communities in a grain crop rotation

“…Increased taxon diversity and evenness is associated with reduced pest pressure (Lundgren & Fausti, 2015); therefore, community-level impacts of NSTs could disrupt natural pest control. In maize, clothianidin treated seed disturbed the overall arthropod community after planting, with several beneficial predators decreasing in abundance (Disque, Hamby, Dubey, Taylor, & Dively, 2018). Neonicotinoids can also negatively impact pollinators (Godfray et al, 2014).…”