Astudy of thermal degradation kinetics on the biological activity of actellic in controlling of aphids ( Myzus persicae) on cucumber

Abstract

Several experiments were conducted at Al – Ramadi distinct / Al – Anbar province, Iraq in 2007 to investigate effect of thermal degradation kinetics of actellic (2-Diethylamino-6-methylprimidin-4-yl-dimethyl phosphorothionate) on the biological activity in controlling of aphids ( Myzus persicae) on cucumber . The insecticide was exposed to six tempertures levels in the laboratory ( 0 , 5 , 10 , 20 , 40 and 60 C˚ ) for five exposal periods ( 1 , 2 , 4 , 6 and 8 h ) before field application in infestation % of aphids and productivity of cucumber were estimated . Resulte showed that actellic activity was decreased at ( 0 C˚) with increasing exposing tempertures where as infestation % was ( 27 % ) at ( 60 C˚) , up to ( 10 % ) at ( 0 C˚ ) lead to decrease productivity of plant with increasing temperatures . The higher average obtained under ( 5 C˚ ) was ( 3347kg / D ) , While it decreased at ( 60 C˚ ) of ( 2815 kg / D ) . The results showed that thermal degradation of actellic which measured by ion phosphorus increased while pH reduced by increasing temperature. The kinetic studies indicated that the rate of reaction is of the first order by drawing the relation between Ln ( Po / Pt ) with time of temperature which showed a linear relation, Dissociation pesticide actellic. Thermodynamic functions actellic degradation calculated such as ( Activation Energy, Enthalpy , Entropy , Gibbs function ) Which is highly effect by temperature .