Effect of Prepared Wettable Powder Based on Beauveria bassiana (Asc., Cordycipitaceae) Blastospores Against the Onion Thrips, Thrips tabaci (Thys., Thripidae)

Formulation of blastospores of entomopathogenic fungi may help to overcome unfavorable climatic conditions and may increase their effectiveness. In the present study, different products of wettable powder of blastospores were prepared for two isolates of Beauveria bassiana and were stored at two different temperature regimes, refrigerator (4±1°C) and laboratory (24±3°C) conditions. After storage durations (24 hours and 30 days), their effects were investigated against second instar larvae of the onion thrips. Results indicated that mortality percent of thrips larvae in blastospore's treatments maintained in laboratory (BML), blastospore's treatments maintained in refrigerator (BMR), new formulated blastospore (NFB) and new blastospore )NB) in 108 spore/ml concentration were 66, 89.4, 92.7 & 91% in B. bassiana EUT105 and 70, 93, 89.8 & 91 % in B. bassiana EUT116, respectively. These results indicated positive effects of storing at low temperature on preserving high viability in treatments maintained in refrigerator than those maintained in the laboratory. The results of this study can be valuable base for research on increasing stability and efficacy of fungal spores, changing or replacement of carrier ingredients in our country.