Population Development and Infestation Rate of Pistachio twig Borer [Kermania pistaciella Amsel (Lepidoptera: Tineidae)] in Pistachio Orchards in Middle Euphrates Valley, Türkiye

Pistachio is a strategic crop for Turkey, and the country ranks third in global pistachio production after Iran and the United States. Numerous pests adversely affect pistachio production, with one of the most significant being Kermania pistaciella Amsel (Lepidoptera: Tineidae). This study was conducted to determine the population development of Kermania pistaciella adults and the infestation rate in shoots and fruit clusters in pistachio orchards of Innaplı, Surtepe and Keskince villages in the Middle Euphrates Valley in 2019. Three delta-type pheromone traps were installed in each orchard. Trap counts were conducted weekly. To determine the pest's infestation rates in shoots and fruits clusters, 100 shoots and 100 clusters were inspected in each orchard. The results showed that the first adult flights of K. pistaciella began in the last days of March. The pest population peaked on April 20 in all three locations, with 1263, 977, and 513 adult trap-1 captured in Innaplı, Surtepe, and Keskince, respectively. After an approximately six-week flight period in nature, the last adult flight was recorded on May 11. Throughout season in Innaplı, Surtepe, and Keskince, a total of 3 306, 2 574 and 1 651 adult trap-1 were captured, respectively. The infestation rates in the terminal shoots were 16%, 12%, and 8% while in fruit clusters were determined as 12%, 9%, and 6% in Innaplı, Surtepe, and Keskince, respectively. In conclusion, K. pistaciella formed a high population in pistachio orchards of the Middle Euphrates Valley, causing infestations above the economic damage threshold. Since chemical control measures have not provided sufficient success against K. pistaciella, the pest population and damage rates can be reduced through environmentally friendly biotechnical control methods, such as mass trapping, which must be implemented by all producers.