K.A.M. Al-Khafaji*, S.A. Khleiwy, S.A. Mahmoud, M.A. Abdallah, S.A. Saleh, A.A. Mezban, A.J. Fayyadh and A.F. Abbas
Agricultural Research Center, Scientific Research Authority, Ministry of Higher Education and Scientific Research, Baghdad, Iraq
*Email address of the corresponding researcher: [email protected]
Date fruits is the most important agricultural product in Iraq. Date palms suffer from many deleterious insects that cause negative impact, and the most important among them is the fig moth larvae of Ephestia caultella that causes yield loss in date fruits on the trees and during storage. This study aimed to develop a bio-pesticide from Enterococcus bacterium isolated from the gut of insect larvae, in addition to develop an application protocol. Five 3rd instars of E. cautella were collected from a laboratory maintenance medium and dissected under the microscope to extract the gut, which was homogenized and enriched with peptone water. A loopful suspension was spread over Pfizer agar. Three isolates were separated on Pfizer agar and suspected to belong to the genus Enterococcus. Biological assay was carried out using a unified bacterial dosage of 105 cells/ml for all treatments. A mortality rate of 63% was observed for Enterococcus spp. designated as isolate KS1, which was chosen for the development of the bio-control agent. The bacteria was identified as E. faecalis KS1 based on biochemical tests, whereas molecular characterization revealed 97% similarity with E. faecium and 95% similarity with E. faecalis. Three treatments were evaluated, including live bacterial culture, heat-killed bacterial culture and cell-free extract from bacterial culture. The results obtained showed 76.7%, 43.3% and 53.3% mortality, for the three treatments, respectively. The estimated LC50 for insect larvae was 3.96×106 live cell/ml and 1.96×104 heat-killed cell/ml.
Entemopathogenic, biofilm formation, heat treatment, median lethal oncentration, LC50.
https://doi.org/10.22268/AJPP-001432