Characterization and Bioassay of Different Commercial Products of B. thuringiensis Against Four Larval Stages and Adults of an Insect Tuta absoluta in Laboratory

Abstract

Among the diversity of insect pests affecting on the tomato crop in the Gaza Strip insect (Tuta absoluta Meyrick). As the damage caused by the larvae that attack the buds, flowers, and fruits. Larvae prefer clusters leaves and flowers, leading to the loss of these clusters as a whole. For its control, farmers mainly use chemical insecticides, which cause adverse effects to the environment and human health. Biological control of pests comes up as alternative, and among many biological agents, Bacillus thuringiensis (Bt) dominate 90% of biopesticide global market. So it was the aim of this study to characterize and find out the best effectiveness of commercial product effective against insect tomato leafminer Tuta absoluta. The first commercial products bacteria B .thuringiensis var kurstaki product (Agerin ®) and second bacterium B. thuringiensis var. israelensis product (Back tosh ®). The purpose is the protection of tomato crop from danger and threat of use of chemical pesticides on humans and the surrounding environment of Gaza Strip. The results showed the mean cumulative corrected % mortality After using B. thuringiensis var kurstaki bacteria from (Agerin®) product at the highest concentration 5 g\l after six days of exposure it reached 75, 73, 71, 71 % for 1st, 2nd, 3rd and 4th instars, respectively. Also, using of B. thuringiensis var kurstaki from (Agerin®) product was affected on the mean cumulative corrected % mortality of adults T.absoluta reached 64 % at the highest concentration 5 g\l after three days of exposure. The mean cumulative corrected % mortality after using B. thuringiensis var. israelensis from (Back tosh ®) product at the highest concentration 14 ml\l after six days of exposure reached 72, 65, 56, 53 % for 1st, 2nd, 3rd and 4th instars, respectively. Also, the using of B. thuringiensis var. israelensis from (Back tosh ®) product was affected on the mean cumulative corrected % mortality of adults T.absoluta. It reached 26 % at the highest concentration 14 ml\l after three days of exposure. Therefore, we conclude that the commercial product (Agerin®) is more effective against four larval stages and adult insect T.absoluta compared with commercial product (Back tosh®).