Analyzing the Counteractive Impact of Bacillus thuringiensis on Oriental Fruit Moth, Grapholita molesta in Peach Orchards of Armavir, Armenia

The present investigation, conducted during 2020–23 under both laboratory and field conditions, was aimed at isolation and evaluating Bacillus thuringiensis (Bt), specifically Bt ^MB-23 and Bt ^Tv-97, against larvae of the oriental fruit moth, Grapholita molesta. The oriental fruit moth is a major pest in peach cultivation in the Republic of Armenia, which causes substantial damage to fruit and leaves.

The Bt strains isolated from naturally deceased larvae were evaluated at a concentration of 600 million spores/ml, both individually and in combination with commercial insecticide at sublethal concentrations of 3x and 10x dilutions. Damage assessment in terms of the number of affected leaves and fruits per tree was recorded and analyzed.

All tested treatments with Bt strains showed high biological efficiency, recording 86.8-97.0% damage reduction as compared to the control. The combination treatments of Bt and chemical insecticide demonstrated the effectiveness of the treatments in pest suppression. Statistical analysis validated the experimental outcomes, showing that overall fruit yield and damage metrics were comparable between treatments and controls, while biocontrol treatments achieved these results with reduced chemical use, confirming the reliability of the findings.