International Journal of Entomology Research

Authors
Abdullah RRH

Abstract
Chitin is the main component of insect cuticle also, it presents in the gut membrane. Thus the use of chitinolytic bacteria or their metabolites to control insect pests is very interesting. In the present work, chitinolytic bacterial isolates were isolated and identified to use them as a bioinsecticide to control the tomato leaf miner insect Tuta absoluta. A total of 18 chitinolytic bacterial isolates were obtained from 6 soil samples. Two isolates were found to be more active in chitinase activity in both broth and solid colloidal chitin medium. These isolates were designated IS16 and IS17. Based on sequence of the 16S rRNA gene, IS16 isolate was similar to Bacillus subtilis and IS17 isolate was similar to Lysobacter enzymogenes. The efficacy of both bacterial isolates was tested against Tuta absoluta by leaf dipping bioassay method. The treatments were supernatant that contains chitinase enzyme and original bacterial culture that contain bacterial cells and chitinase enzyme and bacterial cells solution. The obtained data revealed that the culture which contains cells and chitinase had larvicidal activity more than other treatments. More deformation was observed in larvae when were treated by supernatant which contains chitinase enzyme. This study recommended that the chitinolytic bacteria could be used in IPM programs to control tomato leaf miners for decreasing chemical pesticide usage.