Effect of enhanced biodegradation of carbofuran on the control of striped cucumber beetle (Coleoptera: Chrysomelidae) on muskmelon

Soils traditionally used for muskmelon, Cucumis melo L., production in Indiana were studied for their capacity to develop enhanced (rapid) rates of carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) breakdown. The rate of carbofuran degradation in soils with a history of carbofuran treatment was compared with similar soils with no previous carbofuran treatment. Degradation estimates were based on bioassay with larval western corn rootworms, Diabrotica virgifera virgifera LeConte, and measurement of the release of 14C-CO2 from 14C-carbofuran. Uptake of carbofuran by muskmelon plants growing in enhanced (soil in which a pesticide is rapidly degraded by populations of microorganisms previously exposed to the pesticide or a structurally, related compound) and nonenhanced soils was also estimated. Both estimates of degradation showed rapid loss of carbofuran occurring in history soils as opposed to a much slower rate of degradation in nonhistory soils. Plant uptake of carbofuran, measured by bioassay with striped cucumber beetle, Acalymma vittatum (F.), and residue analysis by gas chromatography-mass spectrometry was dependent upon the concentration of the insecticide in soil. The control of striped cucumber beetle on plants growing in history soils was reduced compared with plants growing in nonenhanced soil