Effectiveness of Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae (Metsch.) (Deuteromycotina: Hyphomycetes) as Biological Control Agents of the Onion Thrips, Thrips tabaci Lind.

Abstract

This experiment was carried out at the experimental farm, Faculty of Agriculture, Tanta University, during 2014 and 2015 seasons, to study the population density of onion thrips, Thrips tabaci Lind.(Thysanoptera: Thripidae) under onion field conditions. In the middel of February the population density exceeded 10 alive thrips per plant which the time of control. Population peak reached during 2nd week of April 2014. Two entomopathogenic fungi Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae (Metsch.) (Deuteromycotina: Hyphomycetes) isolates were treated on T. tabaci in labortatory conditions with concentrations of 104, 105, 106, 107 and 108 conidia/ml. Therefore the LC50 values were 0.9 x 105and 2.9 x 106conidia/ml. for B. bassiana and M. anisopliae isolates, respectively. Accordingly the two isolates were sprayed in the middel of february in the onion field to control T. tabaci with concentrations of 0.9 x 106 and 2.9 x 107 conidia/ml for B. bassiana and M. anisopliae isolates, respectively and compare with Actellic 50% as a recommended pesticide with 500 ml/Fadan. The reduction in insect numbers were 74, 62.87 and 87.08 % for B. Bassiana, M. anisopliae isolates and Actellic 50%, respectively. This result revealed that the two isolates may be effective against T. tabaci in field conditions especially B. bassiana isolate.