Long-term conservation tillage studies: Impact of no-till on seedcorn maggot (Diptera:Anthomyiidae)

A long-term study (12 years) was conducted to determine the feasibility of growing soybean in rotation with corn on the hill land of southeastern Ohio, USA, using conservation tillage practices that included investigating the effect of tillage on populations of seedcorn maggot, Delia platura Meigen. Corn and soybean were grown using various management and conservation tillage practices including no-till, paraplow, and chisel plow, multiple diskings, and conventional tillage. Adult seedcorn maggots were sampled over a 12-year period to assess the impact of tillage practice on population density. No-till and paraplow, where there was little soil disturbance, generally had fewest adults. Chisel plowing caused a slight increase in numbers of adults, although densities were never as high as plowing and/or disking treatments. The largest number of adults were collected from areas where soil was disturbed, either by plowing and disking or by multiple diskings. This study presents evidence that no-till systems do not enhance seedcorn maggot populations and indicates that population increases are associated with tillage systems involving substantial soil disturbance. (C) 1997 Elsevier Science Ltd.