Short‐term effects of methiocarb formulations on pasture earthworms (Oligochaeta:Lumbricidae)

Abstract Methiocarb was applied as spray and bait formulations at both 0.5 and 1.0 kg a.i./ha to the surface of a pasture. Moribund earthworms which subsequently died, appeared on the surface of all the treated plots. The treatments affected the populations of the 2 common earthworm species differently. Their resultant responses can be related to their respective behaviour patterns. Lumbricus rubellus Hoffmeister is a litter‐feeding species and populations of this species declined most. Mature and immature L. rubellus were similarly affected. Allolobophora caliginosa Savigny, a topsoil‐mixing species, was only slightly affected by methiocarb application. Earthworm numbers were lowest for this species, 29% less than control plots, on pasture sprayed with 1.0 kg/ha methiocarb.