The effects of pesticides and crop rotation on the soil-inhabiting fauna of sugar-beet fields. Part I: The crop and macroinvertebrates

The effects of two insecticide treatments (seed-furrow aldicarb, and gamma-HCH sprayed overall), herbicide and crop rotation on pest attack to sugar-beet seedlings, and pest and predator populations, were studied in a 3-year field trial. On continuous-beet plots without insecticide, seedling establishment declined sharply from the first to the third year of the trial due to a build-up in the numbers of pygmy beetles, Atomaria linearis Steph., a sugar-beet pest. Crop rotation, and both insecticides, decreased damage by the pest and thereby increased establishment considerably, in the second and third years of the trial whereas herbicide had no effect. The effects of the insecticides on numbers of creatures caught in pitfall traps varied with species and with insecticide. For example, more Bembidion lampros Herbst., a carabid beetle, were trapped on plots treated with gamma-HCH than on untreated plots, whereas the effect was less marked on aldicarb-treated plots and was not observed in other carabid species with either insecticide.