Effects of chemical pesticides on beneficial and harmful insect populations on four farms in Central Massachusetts

Finding sustainable methods to control pest insects that affect crop yield is a pressing, worldwide concern for agriculture. In recent decades, there has been interest in developing less toxic chemical pesticides, and more sparse regimens for application of these pesticides to avoid also killing beneficial insects during pesticide applications. For this study, insects were collected from four farms in Central Massachusetts (Middlesex and Worcester Counties) to compare the population levels of beneficial and harmful insects at commercial farms using organic vs. chemical pest control methods. Three of the farms used organic insect controls and one of the farms used non – organic chemical insect controls. It was predicted that farms using only chemical pesticides would have lower numbers of both beneficial and harmful insects compared to farms that use organic pesticides. The total number of insects trapped at the four different farms employing different insect control strategies (non – organic chemicals vs. organic) did not have a statistically significant difference. However, there were fewer beneficial predatory beetles (Carabidae: Coleoptera) found at a farm (site the farm with fewer beetles) using non – organic chemical pest controls (Chlorantraniliprole, Lambda-cyhalothrin, and Imidacloprid) compared to
another farm using only one biopesticide, (Spinosad). Our results suggest chemical insect controls have unintended consequences on agroecosystems and merit further study.


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