CARACTERISATION PHENOTYPIQUE ET MOLECULAIRE D’UNE BACTERIE RHIZOSPHERIQUE Bacillus sp. H1 (LT547812) Et Etude De Son Efficacité Entomopathogène CONTRE LA PYRALE DE LA DATTE Ectomyelois ceratoniae

Abstract

Entomopathogenic bacteria occupy a special place in the natural regulation of many insects. It is mainly the species of the genus Bacillus that is mostly used in biological pest control and offers encouraging prospects. We have studied in the laboratory the sublethal effect of an indigenous bacterial strain from a coastal region in central Algeria, on some life parameters of the date palm moth Ectomyelois ceratoniae, a potential pest of palm groves in Algeria. The bacterium was identified on the basis of a molecular study by sequencing the 16s RNA. The characterisation was carried out on the basis of its morphology and certain physiological and biochemical criteria. The bacterial isolate showed different reactions to the identification tests carried out with the ability to degrade several substrates such as lipids, proteins and complex sugars as well as chitin, gelatin and cellulose. The phylogenetic study confirmed that the bacterium belongs to the genus Bacillus with a high percentage of similarity for Bacillus thuringiensis. Biological activity of the bacterium was tested for food intake, pupation and emergence rates in mature caterpillars (L4 and L5) of both male and female sexes of the moth of the date over a 22-day period. The results obtained show a significant decrease in the three studied parameters, which is all the more important in female larvae than in male larvae, under the effect of the different tested doses (D1, D2 / l, D3, D4 et D5) compared with controls. The amount of food ingested gradually increases from the 1st to the 5th day then it tends to decrease and the caterpillars stop feeding much earlier than the controls. The pupation and emergence rates of treated caterpillars remain low, not exceeding 40%.