Nematode response to methyl bromide and 1,3-dichloropropene soil fumigation at different temperatures

Abstract

Several heat-based methods, such as soil solarization, are being developed as alternative practices for managing soil-borne pests and pathogens. The effectiveness of these practices is often inconsistent or marginal, thus commanding the need for their integration with other methods. The main objective of this study was to determine synergistic interaction between soil fumigants and temperature. Soil infested with citrus nematode Tylenchulus semipenetrans was exposed to methyl bromide or 1,3-dichloropropene at various temperatures. Fumigant degradation was concurrently measured and concentration-time index (ct) was calculated and correlated to the recovered nematode population. In untreated soil, nematode survival was not affected by temperatures of 20–30 °C, but was strongly reduced at ≥ 40 °C. In fumigated soil, nematode suppression was much greater at 30 °C than at 20 °C, and the ct required for nematode elimination at 30 °C was < 50% of that needed at 20 °C for both fumigants. These results suggest that these fumigants became more active with increasing temperature in the sub-lethal temperature range. It also implies that, when integrated with a heat-based practice, reduced rates of fumigants may provide adequate pest control, thus minimizing the environmental input of chemical fumigants. © 2000 Society of Chemical Industry