Sublethal effects of an organophosphorous insecticide, dimethoate, on the isopod Porcellio scaber Latr

Dimethoate was more toxic to Porcellio scaber when mixed with soil than with food. LC(50) for the insecticide mixed with soil was <50% from that obtained with food. Exposure through artificial soil (OECD) was less effective than that through natural soil (LUFA 2.2). The influence of the soil on the growth retarding effect of dimethoate was calculed as EC(10) OECD/EC(10) LUFA and ECH, OECD/EC(50) LUFA, and these indices (SIIs) were 4.38 and 2.35, respectively. The 50% effective dimethoate concentration (EC(50)) for the sublethal outputs, growth and reproduction were approximately one half of LC(50). The sublethal sensitivity indices (SSIs) of growth and reproduction, calculated as LC(50)/EC(10) were 8.09 and 8.94, respectively. (C) 1997 Elsevier Science Inc.