Influence of pesticide use on soil macrofauna in a fruit growing area

Abstract

ABSTRACT The action of pest insects directly affects agricultural productivity, thus requiring a large number of insecticide applications for their control. The main products used come from the organophosphate, pyrethroid and spinosyn groups, but indiscriminate use of these products can cause negative effects, especially on soil organisms. Thus, the objective of this study was to evaluate changes in soil macrofauna caused by the application of insecticides in a fruit production area. The insecticides malathion, deltamethrin and spinetoram were applied at the maximum dose indicated by the manufacturer, using twice the volume of solution for terrestrial applications. The experimental design was randomized blocks, consisting of four treatments with five replicates each, distributed in five blocks. After application, soil macrofauna was evaluated according to the Tropical Soil Biology and Fertility (TSBF) method. Individuals were quantified and identified by taxonomic groups for further determination of density, richness, Shannon-Weaver diversity index (H') and Pielou evenness index (J’). Malathion, deltamethrin and spinetoram did not affect the total density, as well as the density per taxonomic group, except for the Coleoptera group, which had lower density of individuals per m2 in soil treated with malathion and deltamethrin, differing from the soils treated with spinetoram and from the control treatment. Therefore, it is found that deltamethrin applications reduce the density of Coleoptera in the soil under the conditions tested.