Effect of Some Bio- insecticides against Tetranychus urticae Koch

Abstract

Efficacy of fife bio-insecticides against Tetranychus urticae Koch. The most effective for controlling T. urticae , Marshal, followed by the botanical insecticide, Bemistop, Biosect, Admiral and Vertimec .Results revealed that, the addition of Marshal, at its half-recommended rate to Vertimec and/or Bemistop at two application rates had increased obviously their toxicity against and T. urticae. Than separately, and exhibited an additive effect at the two sprays. In addition, results obtained from addition of the botanical compound, Vertimec at 200 and 100 cm 3 /100L. to Admiral at its recommended and half-recommended rate at the two sprays increased its effectiveness than separately and induced an additive effect at two sprays with the two application rates. This increase was determined and termed as additive effect in which the total mortality of the combination is higher than the mortality of summation of each compound respectively.