Bioassay of wettable powder formulation of Lecanicillium muscarium blastospore on Aphis gossypii

Wettable powder formulation of L. muscarium blastospore was evaluated on second nymphal instars of A. gossypii (Glover) in six experiments. Treatments consisted of fresh blastospores and fresh formulated blastospores with six concentrations and distilled water as control, arranged in a completely randomized design with three replications. The experiments were separately repeated one and seven months later, with previous formulated blastospore stored in laboratory conditions (22±2ºC temperature) and in refrigerator (4±1ºC temperature) at similar conditions. Variance analysis of experiments demonstrated significant differences among treatments and concentrations (p<0.01). Comparing means showed that 1 month formulated blastospore stored in refrigerator with 56.19±7.28% and 7 months formulated blastospore stored on laboratory shelf with 15.15±1.83 % had the highest and the lowest mortality percent, respectively. Comparison of lower and upper confidence limits of LC50s showed significant differences only between 7 months formulated blastospore stored on laboratory condition and the other treatments. Comparison of lower and upper confidence limits of LT50s showed significant difference only between 108 spore/ml. of 1 month formulated blastospore stored in refrigerator and the others. Result of recent experiments illustrated that produced blastospores on potato extract, and prepared formulation was virulent on A. gossypii.