Sulfoxaflor Residues in Pollen and Nectar of Cotton Applied through Drip Irrigation and Their Potential Exposure to Apis mellifera L.

Jiang Jiang,Zhao Zhao,Chen Chen,Xu Xu,Zhang Zhang,Tian Tian

doi:10.3390/insects11020114

Jiang Jiang, Zhao Zhao + Show 4 more

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https://doi.org/10.3390/insects11020114

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Abstract

Systemic insecticides have been applied through drip irrigation for controlling crop pests, but few studies have addressed potential negative effects of the application on non-target organisms. In this study, the safety of sulfoxaflor applied at 450 or 700 g a.i. ha−1 through drip irrigation at different times before flowering or during flowering to honey bee (Apis mellifera L.) was studied in 2016–2017 in a cotton production field in Xinjiang, China. Results showed that sulfoxaflor residues in pollen and nectar of cotton treated with sulfoxaflor at 450 g a.i. ha−1 before and during flowering through drip irrigation were either undetectable or no more than 17 μg·kg−1. Application of sulfoxaflor at 700 g a.i. ha−1 before flowering resulted in ≤ 14.2 μg·kg−1 of sulfoxaflor in pollen and < 0.68 μg·kg−1 in nectar. Sulfoxaflor applied at this higher rate during flowering had the highest residue, up to 39.2 μg·kg−1 in pollen and 13.8 μg·kg−1 in nectar. Risk assessments by contact exposure and dietary exposure showed that drip application of sulfoxaflor at the two rates before or during flowering posed little risk to honey bees. Thus, drip application of sulfoxaflor could represent an environmentally benign method for controlling cotton aphid.

Highlights

Drip application of chemicals or chemigation is a method of delivering insecticides to plant root zones for the control of crop pests [1,2,3,4]
Our results showed that the drip application of sulfoxaflor at the two rates posed little risk to honey bee during cotton production in Xinjiang
Sulfoxaflor concentrations in pollen of plants treated with 700 g a.i. ha−1 during the flowering stage from day 5 to day 7 were significantly higher than the other treatments (F = 11.40, df = 13, 28, p < 0.001), but there were no significant differences within the other treatments

Summary

Introduction

Drip application of chemicals or chemigation is a method of delivering insecticides to plant root zones for the control of crop pests [1,2,3,4]. Increasing reports have shown that insecticides applied via drip irrigation exhibited higher efficacy against crop pests than the conventional foliar spray method [2,3,4,6,8,9,10]. Xinjiang is the world’s most important cotton-producing region, accounting for 10% of the annual global cotton lint production and about 50% of the cotton yield in China [11]. Cotton production in Xinjiang is primarily irrigated through a drip system [12,13]. Cotton farming has served as an engine of economic growth and provided income to millions of farmers in cotton production regions [14]

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