| Abstract: | The impact of two insecticides applied at locally practised frequencies on the population fluctuations of soya bean arthropods was studied at two farmers' field sites in Indonesia. Temporal recovery was determined from observations taken consecutively at short intervals. Spatial recovery was determined from observations taken at diVerent distances from the unsprayed surroundings. Monocrotophos suppressed predaceous ants, spiders and beetles, but did not reduce all phytophages. Lambda-cyhalothrin had a large impact on generalist predators and suppressed phytophages. Multiple regression analysis showed that temporal recovery was low for generalist predators and highest for lepidopterous larvae, indicating a potential to resurge after spraying. Spatial recover was observed for spiders, beetles, crickets and lepidopterous larvae (Galerucinae and Empoasca sp.), indicating that the presence of refuge areas may encourage recovery. To reduce the dependency on insecticides, farmers require training in phytophage-predator-insecticide interactions through field exercises. |
