الفهرس 
Introduction
Stement of the problemOnly 14 pages are availabe for public view
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Abstract
Certain synthetic pyrethroids are becoming of ever— increasing importance as insecticides for controlling the yptian cotton leafworm Spodop.tenct tto’taUo (Boisd.) Development of resistance in the cotton leafworm, cross— resistance and synergism of pyrethroids have been examined.
Effect of post-treatment temperature on toxicity of Dyrethroids and kinetic properties of esterase and oxidase
‘ctivity in susceptible and pyrethroid selected strains were also investigated.
Five synthetic pyrethroids (C-permethrin;tka.n6-per- :.athrin; cypermethrin; fenvalerate and deltamethrin) ; two carbamates (methomyl and aminocarb) ; five organophosphates (chiorpyrifos; phosfolan; mephosfolan; parathion and malathion) and three polychlorinated insecticides (Endrin, )ieldrin and lindane) were applied topically to fourth star larvae of susceptible laboratory strain of Spodop.te.ict. UonaA (Boisd.) to determine their relative toxicity. e LD50 values had indicated that the synthetic pyrethroids ere generally the most active compounds. Deltamethrin was the most potent compound (LD50 = 0.42 ug/gm) followed by ypermethrin (0.72 ug/gm); c.-permethrin (1.1 ug/gm); itan-permethrin (1.5 ug/gm) and fenvalerate (3.0 ug/gm)
Selection of the cotton leafworm with tn.czn4-permethrin cypermethrin for 28 and 20 generations, respectively, at D7580 level resulted in an increase in LD50 values of 5.5
3.7 fold as compared with the parent strain for the elective agents, respectively.