Efficacy of Bacillus thuringiensis and mineral oil against Phyllocnistis citrella stainton (Lepidptera: Gracillariidae)
2007
Besheli, B.A. (Mazandaran Univ., Sari (Iran). Dept. of Plant Protection)
A laboratory experiments was conducted to examine the efficacy of Bacillus thuringiensis for control of citrus leaf miner, Phyllocnistis citrella Stainton, in isolated citrus leaves in Mazandaran province, Iran. Several preparations of Bt tested at the concentrations of 0.5, 1, 3 and 6 g per liter of water with or without mineral oil in these bioassays. In all tests, the bacterial suspensions or mineral oils were applied on the leaves of citrus with second or third instars of leaf miner larvae in a leaf-dip bioassay. For all concentrations of Bt treatments, with the exception of 0.5% the number of larval mortality was significantly (P less than 0.01) decreased compared to un-treated control group. The larval mortality positively correlated with Bt concentrations. The number of larvae per leaf, were significantly (P less than 0.01) reduced by treatment with Bt plus mineral oil. Treatment with Bt plus mineral oil reduced the CLM larvae numbers to a level not significantly different from treatment with Bt alone. These data suggest that the activity of Bt is enhanced, probably due to increased penetration of Bt into leaf cuticles by treatment of mineral oil.
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