MSU scientists study tie between insecticides, bee health

MSU scientists study tie between insecticides, bee


Just mentioning bees and pesticides in the same sentence is sure to get a buzz,” said Angus Catchot, an entomologist with the Mississippi State University Extension Service. Media skirmishes about bee health, agriculture practices and the role of pollinators in food production are a mixture of fact, propaganda and general misunderstanding, Catchot said. “The plight of bees and beekeepers facing substantial losses over the past several years has motivated scientists all over the world to search for the causes,” he said. “As much as everyone wishes we could discover one simple fix or find one specific cause that could be eliminated, our research at MSU is discovering just how complex the relationship is between bees and the environment.” Neonicotinoids: friend or foe? One culprit suspected to be a serious threat to honeybee colonies is neonicotinoids, or neonics. In 2013, Europe banned their use for two years. The average consumer may wonder why the U.S. does not do the same, or why farmers would want to use something that might damage bees, when the pollinators seem to be in such a precarious position. It helps to understand why neonics are important to row crop farmers in the Mid-South, Catchot said. “First, Mississippi’s major row crops — corn, cotton and soybean — do not require honeybees for pollination, but they are magnets for all kinds of insect pests above and below the ground,” he explained. “Neonics are used primarily as seed treatments, which means they coat the seeds and first address pests in the soil. Neonics are also systemic, which means they move through the plant as it grows from seed into seedling. But the insecticide is not permanently present in the plant.” What research shows… Catchot said the seed treatments provide protection for about 21 to 28 days after planting to give young plants a chance for survival. Unlike treatments applied after seedlings emerge, seed treatments prevent plant death or loss of vigor due to below-ground insect pests feeding on developing root tissue and provide a short-term residual effect in the plant as it emerges. “Mid-South entomologists have conducted a lot of research on whether or not neonics are present in the nectar or pollen of our major row crops,” Catchot said. “Soybeans are the crop bees prefer to forage on based on our surveys, and in soybeans, we found zero occurrence of neonics in the flowers of the plant when the soybeans were planted with a neonic seed treatment.” In cotton, they found no occurrence of neonics in the nectar and very low occurrence in the pollen. “In corn, we did find low levels about 20 percent of the time, and they ranged from about three to six parts per billion, but they were more prevalent with chemical rates greater than what is typically used in the Mid-South,” he said. “Based on our research, it does not appear very likely in our region of the country that bees are picking up neonics at any appreciable level from nectar or pollen in the major row crops we grow.” Further research by Catchot’s group indicates 99 percent of the total amount of pesticide applied as a seed treatment in these three crops is gone before the plant produces flowers.

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