This study was conducted to evaluate the effectiveness of Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) release with as well as without Bacillus thuringiensis var. kurstaki (Berliner) in biological control of Cydia pomonella (L.) (Lepidoptera: Tortricidae) in the Galaxy Gala apple variety grafted onto M9 rootstock in 2016. | Turkish Journal of Agriculture and Forestry Turk J Agric For (2017) 41: 201-207 © TÜBİTAK doi: Research Article Efficacy of Trichogramma evanescens and Bacillus thuringiensis var. kurstaki in control of Cydia pomonella (L.) in Turkey 1, 1 2 3 3 Sevcan ÖZTEMİZ *, Ali KÜDEN , Serpil NAS , Işılay LAVKOR Department of Plant Protection, Faculty of Agriculture and Natural Sciences, Düzce University, Düzce, Turkey 2 Department of Horticulture, Faculty of Agriculture, Çukurova University, Adana, Turkey 3 Biological Control Research Institute, Adana, Turkey Received: Accepted/Published Online: Final Version: Abstract: This study was conducted to evaluate the effectiveness of Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae) release with as well as without Bacillus thuringiensis var. kurstaki (Berliner) in biological control of Cydia pomonella (L.) (Lepidoptera: Tortricidae) in the Galaxy Gala apple variety grafted onto M9 rootstock in 2016. Four treatments were analyzed: releasing T. evanescens alone (TE), applying B. thuringiensis var. kurstaki (BT) alone, applying both (TE + BT), and a control (C) without any application at all. The experiment design entailed randomized blocks with four replicates. In each generation of the egg stage, 100,000 parasitoids per hectare were released twice (1440 parasitoids/plot), with an interval of 7–10 days. In the larval stage, BT was applied twice for the first generation and once for the second. Weekly counts were performed regularly. The decrease in egg count was in TE, in BT, and in TE + BT plots. The decrease observed in larval numbers was 68%, , and , respectively. Egg parasitization rates varied between and . At harvest, fruit infestation rates were and in TE and BT plots and just in the TE + BT plot, versus 34% in the control plot. Promising .