Captan is a trichloromethyl sulfenyl fungicide that degrades into thiophosgene, a highly reactive compound that reacts with thiol and non-thiol proteins, in cells.¹It reduces radial growth of and starch depletion byA. fumigatuson the leaf surface ofA. tenuiswhen used at a concentration of 50 μg/ml.²Captan (50-1,000 mg/kg) increases the number of micronuclei and chromosomal aberrations in polychromatic erythrocytes in bone marrow in mice.³It also induces chromosomal aberrations in spermatocytes and sperm head abnormalities in mice. Captan reduces survival of adult male and female alfalfa leafcutting bees (M. rotunda) when applied topically or administered in the diet at concentrations of 150-684 and 24.45-48.9 g/L, respectively.⁴

1.Long, J.W., and Siegel, M.R.Mechanism of action and fate of the fungicide chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) in biological systems. 2. In vitro reactionsChem. Biol. Interact.10(6)383-394(1975) 2.Kithubutheen, A.J., and Pugh, G.J.Effects of fungicides on Aspergillus fumigatusAntonie Van Leeuwenhoek45(2)303-312(1979) 3.Feng, J.Y., and Lin, B.Y.Cytogenetic effects of an agricultural antibiotic, captan, on mouse bone marrow and testicular cellsEnviron. Res.43(2)359-363(1987) 4.Huntzinger, C.I., James, R.R., Bosch, J., et al.Fungicide tests on adult alfalfa leafcutting bees (Hymenoptera: Megachilidae)J. Econ. Entomol.101(4)1088-1094(2008)