Organic farming promotes natural control of weeds by promoting seed predators

Photo credit: Pavel Kirillov Photo credit: Pavel Kirillov

Numerous studies have demonstrated that organic farming promotes biodiversity and increases biological control of pests by supporting beneficial insect predators that prey on insect pests.  Now, a recent study has found that increases in beneficial insect predators on organic farms can help control weeds by consuming weed seeds. Researchers from Germany collected the seed-eating insect Harpalus affinis from conventional and organic fields of winter wheat that were surrounded by other organic and conventional farms.  They found 3.5 times more beneficial seed predators in organic fields than conventional fields when those fields were surrounded by conventional fields. “The results of the present study suggest that organic farming at local and landscape scales enhances the potential of species to control arable weeds by increasing activity densities and intraspecific body size,” the researchers wrote.