اثر چند فراورده بیولوژیک در کاهش جمعیت لیسه زالزالک Yponomeuta padella در استان چهارمحال و بختیاری

Due to the droughts of recent years, human interference and indiscriminate grazing of livestock from pastures, minor and tertiary pests have become emerging pests, they caused to severe attack to natural resources, pastures and environment. One of such this pests is hawthorn ermine moth Yponomeuta padella which attacks the important and valuable species of wild hawthorn pasture tree Crataegus spp. in the forests of Bazofat region in the west of Chaharmahal and Bakhtiari province. This pest destroys the greenness of the plant, weaving web, branches are extensively die back, leading to disruption of photosynthesis, attracts dust and eventually dries the tree. Due to the lack of contamination spreading to other forest areas of the province, the method of destroying the contamination centers should be done immediately. For this purpose, an experiment was designed to investigate the effect of several biological products. One of the important centers of Sharmak village of Koohrang city was selected in the spring of 2023.This experiment was conducted in three treatments and three replications in a completely randomized design. The treatments include BT biological product (with wettable powder formulation) produced in the Fanavari Zist Tabiatgara company at the ratio of (1kg/ha), Azadirachtin herbal product (Nimazal) 1% produced by Zistbani Paya (2lit/ha) and spraying with water was chosen as control. Nine stations at a distance of 500 meters from each other and each station with an area of one 1000 square meters were selected in the region. Spraying was carried out in the first week of May 2023 by a lance tractor back sprayer, and five and ten days after spraying, visits and sampling were done by counting the active of pest colonies. The data were analyzed with SAS and Excel software, and variance analysis tables and regression charts were checked on pest frequency. The results showed that Bt powder treatment with 37% effect, followed by Nimazal treatment with 19% and control treatment with 5% effect had the most effect on the pest. Therefore, the microbial product of BT with powder formulation had the greatest effect on larvae and according to the sensitivities and prohibitions in the use of chemical pesticides in pastures and natural resources, it can be used to manage this pest in contaminated areas. In addition, more research is suggested regarding the protected use when necessary to destroy the center of emerging pests in order to prevent their establishment and localization.