Mongabay: Corn expansion is hurting ladybugs

Expansion of corn acreage to meet ethanol targets is reducing the ability of beneficial insects to control pests, a loss valued at $58 million in the four states studied (Michigan, Iowa, Minnesota and Wisconsin), report researchers writing in the journal Proceedings of the National Academy of Sciences.

“Corn is a less favorable habitat for many ladybird beetles (ladybugs) and other beneficial insects that feed on pests such as the soybean aphid,” said Doug Landis, a professor of entomology at Michigan State University and lead author of the study. “As we plant more corn, we reduce the ability of that landscape to supply beneficial predators to control pests in soybeans and other crops. This results in increased pesticide use and yield losses. This research estimates the value of this biological pest control service in soybeans (in the four states) to be about $240 million each year.”

“Over-reliance on any one crop is likely to reduce the value of natural control of pest insects by beneficial insects,” added Scott Swinton, professor of agricultural, food and resource economics at Michigan State University and a co-author of the paper. “If we look at farmers who grow only corn and soybeans, increasing corn acreage and reducing soybean acreage will probably mean higher costs for soybean pest control. Beneficial insects help control pests so growers have lower pest control costs.”

Mongabay