Determination of the effect of pesticide and biopesticide use against gray mold (Botrytis cinerea) disease in strawberry on fruit quality and residue

This thesis study was prepared to draw attention to the residue problem, which has become important in terms of food safety with the increasing use of pesticides, and to reveal the potential of biopesticides as safe alternatives to pesticides. The research was carried out in Çukurova University, Faculty of Agriculture, Department of Horticulture, Research and Application greenhouses in 2023 and 2024; two strawberry varieties, Rubygem and Calinda, were used. Signum® WG (boscalid + pyraclostrobin) was applied as chemical pesticide and T-22 Planter Box (Trichoderma harzianum) and Mikoks (Thyme oil) were applied as biopesticides. Rubygem cultivar was generally superior in many quality parameters, while Calinda cultivar was superior in some external colour and pesticide residue parameters. The highest quality values were generally obtained with T-22 (30) and Signum (30 or 100) treatments. The highest pesticide residue levels were observed in Calinda variety and Signum (100) treatment. In terms of sampling time, day 1 showed the highest values for most quality parameters and all residue levels. The results showed that the treatments had significant effects on both fruit quality and pesticide residues. Keywords: Strawberry, Quality, Residue, QuEChERS, Pesticide