Soil and foliage arthropod communities in conventional, reduced and no-tillage corn (maize, Zea mays L.) systems: A comparison after 20 years of continuous cropping

Abstract

The influence of long-term (20 years) tillage - moldboard-plowed, reduced- and no-tillage practices - on soil-inhabiting and canopy arthropod communities was examined in corn (maize) systems during a 3-year period. Effects of a soil-applied insecticide (terbufos) on the anrthropod communities were also investigated. Damage by 3 major insect pest species of maize were evaluated: black cutworm, Agrotis ipsilon (Lepidoptera: Noctuidae); European corn borer, Ostrinia nubilalis (Lepidoptera: Pyralidae); corn rootworm beetles, Diabrotica spp. (Coleoptera: Chrysomelidae). Cutworm damage to corn was lowest in the conventional-tillage treatment. Damage by this species was greater in soil-applied insecticide treatments versus no-insecticide treatment. Neither tillage treatment nor insecticide usage had a significant impact on European corn borer damage to corn. Rootworm feeding on corn varied from year to year, with no discernible effect of tillage treatment on damage levels. Total numbers of microarthropods (mites and collembola) were lowest in the conventionally- (moldboard-) plowed treatments and highest in no-tillage treatments. Insecticide treatment significantly increased oribatid mite density, but consistently lowered (although not significantly so) mesostigmatid mite populations. Insecticide application had little if any noticable influence on collembolan (springtail) numbers. With macroarthropod populations, there was a trend toward greater numbers of ground beetles and spiders in the no-tillage systems. Corn rootworm and ladybird beetles (Coccinellidae) accounted for over 95% of the arthropods collected from the corn foliage. With the exception of 2 sampling dates, western corn rootworm beetle density was greater in no-tillage compared with reduced- and conventional-tillage treatments. Ladybird beetle populations were not affected by tillage or insecticide treatments.