Influence of four commonly used pesticides on the survival, growth, and reproduction of the earthworm Aporrectodea trapezoides (Lumbricidae)

Abstract

The effects of 4 commonly used pesticides, endosulfan (insecticide), fenamiphos (nematicide), methiocarb (molluscicide), and ridomil (fungicide) on the survival, growth, and reproduction of the earthworm Aporrectodea trapezoides (Lumbricidae) were measured in laboratory and field experiments. When the earthworms were exposed to the pesticides on moist filter paper for 48 h, fenamiphos and, to a lesser extent, endosulfan caused significant mortality. In contrast, the survival of A. trapezoides was rarely affected by the pesticides during exposure for 5 weeks in pots and cages containing soil (only noted under 10 × normal application rate of endosulfan against adult worms). However, endosulfan did significantly reduce the weight of juvenile A. trapezoides within 5 weeks when applied to soil at normal application rate in both the field and laboratory. Fenamiphos did so at normal application rate in the field only. Fenamiphos and methiocarb reduced earthworm weight in the laboratory when applied at 10 × normal rate. The clitella of adult earthworms regressed with exposure to endosulfan at normal rate and also exposure to fenamiphos at 10 × normal rate. Cocoon production was inhibited by endosulfan and fenamiphos at normal application rates and methiocarb at 10 × normal rate. The use of some pesticides, in particular endosulfan, could significantly reduce the establishment of abundant and beneficial populations of earthworms in Australian pastures.