*A part of Ph D thesis of D.C. Sharma. Department of Entomology-Apiculture, HPKV, Palampur, Distt. Kangra-176 062. India
Department of Entomology-Apiculture, Dr.Y.S. Parmar University of Horticulture and Forestry, Solan (H.P.) 173 230, India.
Online published on 3 November, 2011.
The bio-efficacy of hexachlorocyclohexane (HCH), pp’-DDT, fenvalerate, carbaryl and methyl parathion was tested singly and in combination against Corcyra cephalonica, Staint, Pieris brassicae linn and Schistocerca gregaria, Forsk. The order of their toxicity to C. cephalonica larvae was fenvalerate > gamma-HCH > methyl palathion > carbaryl > p'p’ -DDT. The insects were immune to alfa-HCH and beta-HCH. The two isomers synergised the toxicity of insecticides. Alfa-HCH was twice as effective as beta-isomer. It gave maximum synergist ratio (2:20) with p p’ -DDT and was followed by its combination with fenvalerate and carbaryl.
