Toxicity values of DEET to three mosquito strains and the housefly.

Letters after 95% confidence intervals (CI) represent statistical significance for LD50 or LC50 values among species within a given toxicity measurement column. Values not labeled by the same letter represent statistical significance (PaLC50 in the WHO filter paper assay.bLD50 by topical application in ng of compound/mg of mosquito weight.cLD50 (same units) by topical application after 4 hr pretreatment with 200 ng PBO.dSynergism ratio = LD50 with DEET alone/LD50 with DEET + PBO.