Researchers say they now know what allows some Western corn rootworms to survive crop rotation, a farming practice that once effectively managed the rootworm pests. The answer to the decades-long mystery of rotation-resistant rootworms lies – in large part – in the rootworm gut, the team reports.
The findings appear in the Proceedings of the National Academy of Sciences.
Differences in the relative abundance of certain bacterial species in the rootworm gut help the adult rootworm beetles feed on soybean leaves and tolerate the plant’s defenses a little better, the researchers report. This boost in digestive finesse allows rotation-resistant beetles to survive long enough to lay their eggs in soybean fields. Their larvae emerge the following spring and feast on the roots of newly planted corn.
“These insects, they have only one generation per year,” said University of Illinois entomology department senior scientist Manfredo Seufferheld, who led the study. “And yet within a period of about 20 years in Illinois they became resistant to crop rotation. What allowed this insect to adapt so fast? These bacteria, perhaps.”
Controlling rootworms is an expensive concern faced by all Midwest corn growers, said study co-author Joseph Spencer, an insect behaviorist at the Illinois Natural History Survey (part of the Prairie Research Institute at the U. of I.). Yield losses, the use of insecticides and corn hybrids engineered to express rootworm-killing toxins in their tissues cost U.S. growers at least $1 billion a year.
Read more at: Phys.org