زیست شناسی، خسارت و تغییرات جمعیت کرم خراط گردو، Zeuzera pyrina L.، در استان چهارمحال و بختیاری

Leopard moth (Zeuzera pyrina L.) is one of the most important wood borers of walnut in different parts of Iran especially Chaharmahal va and Bakhtiari province. Unfortunately, this pest has outbroken in Saman and Shahre-kord orchards and is rapidly spreading to other areas in recent years. In this research, biology, damage and population fluctuation were studied (2007 to 2016) in Chaharmahal va Bakhtiari province for 12 years. Studies showed that the pest had one generation per year and hibernation was in the form of larvae inside the trunk and main branches. Adults’ emergence started in the middle of May depending on the climate conditions, and the peak of male moth population generally occurred in early June. The eggs were laid individually next to the buds and first instar larvae entered the young branches directly at the same place. From mid-September, the larvae gradually moved to the lower parts of the tree and entered the main branches and trunk. During the survey period, the average number of captured moth (in each trap), the percentage of infested branches per tree (in August), the number of active holes in each tree (in November) and the infested area (hectares) were calculated as 49.83 ± 4.84, 57.91± 4.02, 37.83 ± 4.97 and 566.6 ± 53.89, respectively. The highest number of captured moth observed during 2017-2018 and the lowest observed during 2006-2007 and 2012-2013 growing season. The same results were observed for percentage of infested branches and the number of active holes in each tree. The infested area (hectares) of walnut orchards increased from 100 hectares in 2006-2007 to 1100 in 2017-2018.