Impact of Chemical Pesticides on Survival and Feeding Rate of the Woodlouse Porcellio Scaber (Isopoda, Oniscidea) in Benghazi, Libya

Studies were conducted for 21 days on the impact of nine commonly sprayed chemical pesticides in the agroecosystems of Benghazi, Libya, on the survival and feeding rate of the woodlouse Porcellio scaber Latreille, 1804. These pesticides were Bomex, Lannate (carbamate insecticides), Anthio, Supracid (organophosphorus insecticides), Cyperkill, Sumicidin (pyrethroid insecticides), Roundup (herbicide), and Tachigaren, Topas (fungicides). OP insecticides and herbicide were found to be toxic to these woodlice causing high mortality, whereas the survival was comparatively better in those exposed to carbamate insecticides and fungicides. Significant differences in the percentage mortality existed between control and pesticide-treated P.scaber (F=20.64; p 0.01), between those treated with different pesticides (F=3.79;p 0.01), and with different concentrations (0.5, 1,2 and 3 ppm) of pesticides (F=24.36;p 0.01). The feeding rates of P.scaber were adversely affected in those exposed to Topas (fungicide), Sumicidin (pyrethroid insecticide) Roundup (herbicide) and Supracid (OP insecticide). Differences in feeding rates between control and pesticidetreated P. scaber (F= 10.87; p 0.01) and between those kept in different concentrations of pesticides (F=24.87; p 0.01) were significant. The modes of action of different pesticides on P. scaber were discussed. The importance of protecting these beneficial non-target organisms against pesticide hazards has been stressed