RESUMO
Many trials were carried out for formulation of the organophosphorous insecticide, chlorypyrifos, as emulsifiable concentrate [EC] 48% by using local raw materials and products which are: solvent [xylene], co-solvent [n-butanol and dimethyl formamide] and many surfactants which used as emulsifiers, wetting and spreading agents. It was found that only four formulas [CP23, CP24, CP32 and CP33] passed successfully through the physico-chemical properties according to the world recommendation which are: emulsion stability test, foam test, free acidity or alkalinity, flash point, cold test and accelerated storage. This study also included the comparison between the locally formulated chlorpyrifos against commercial formulation [pestiban] under recommended field dilution rate through: 1-Physico-chemical properties [surface tension viscosity, pH and electrical conductivity] 2- Insecticidal efficiency against cotton leaf worm infested cotton plant 3- Deposit and residue of chlorpyrifos on treated cotton leaves. Results obtained indicated that all locally formulated and commercial chlorpyrifos showed good insecticidal efficiency against cotton leaf worm according to the Ministry of Agriculture recommendations but the locally formulated were the best than the commercial one, where deposit on treated plant leaves increased by decreasing surface tension, decreasing pH value with increasing electrical conductivity and increasing viscosity of spray solution, then due to increasing its insecticidal efficiency