Garlic (Allium sativum L., Alliaceae) is consumed at all stages from fresh to dry in Turkey. Major harmful factors, pests for example, bring about a significant loss in garlic production. Studies carried out in Kastamonu garlic areas to determine the harmful pests revealed that the important harmful pest was Delia platura Meigen, (Diptera: Anthomyiidae) in the garlic fields. Population dynamics of D. platura was studied using yellow sticky traps in autumn and spring seasons of planting garlic fields. Plants were checked with trap controls and searched for D. platura on garlic plants. Plants tested were recorded as infested and non-infested. The testing of traps finished in two weeks after the harvest. As a result, D. platura, the first emergence of the adult, was detected on March 21, 2017 in autumn planting and in spring planting. In the autumn planting, the highest number of adults caught in traps was on April 2015 with 4 adult/trap/week. In spring planting, the first adult in the trap was 1 adult/trap/week on 14 March, 2015. The study conducted in 2017, the first time of adult determination on trap was on March 18, 2017 in autumn planting. In spring planting, the first adult emerged on March 18, 2017.