• Muralikrishna, P.V.G.
  Nagarjuna University
  
• Venkateswarlu, K.
  Nagarjuna University
  

Soil algae, particularly blue-greens, have been implicated in the enrichment of soil due to their ability to fix nitrogen. The intensive and indiscriminate use of pesticides such as parathion, carbaryl and endosulfan against many insect pests of rice, cotton, tobacco and other crops might be harmful to the native algal population in soil. Toxicity of certain of these agrochemicals to algae was studied mainly in pure cultures (Singh 1973, Das and Singh 1977, Kar and Singh 1978). The impact of pesticides on the native algal flora in soil has not been investigated. This paper presents the effect of three commonly used insecticides viz., parathion [0, 0-diethyl 0-(p-nitroohenyl) phosphorothioate], carbaryl (1-Naphthyl N-methylcarbamate) and endosulfan (6,7,8,9,10, 10-Hexachloro-1, 5, 5a, 6, 9, 9a-hexa-hydro-6, 9-methano-2, 4, 3-benzodioxathiepin-3-oxide), on the algal population in an lateritic soil under two moisture levels.