بررسي آلودگي درختان راش به شپشك پنبه اي FAQISUQA BARSPAR)HOM.ERIOCCIDAE( CRYPTOCOCCUS در استان گيلان

Study on infestation rate of Beech trees to Cryptococcus fagisuga Barspar in Guilan province.

Cryptoccocus fagi Barspar is one of the major pest of beech stands in Iran. The main purpose of this study was to investigate population density of the pest on Beech trees as well as effecting of environmental factors. Research was carried out in 851 ha. of Shenrood forest in Siyahkal region in the eastern part of Guilan province. Beech trees were selected randomly with lattice in 200x250 m dimensions. Results of data analysis of variance showed that: a) This pest infested beech trees in lower section of tree trunks. b) About 23% of beech trees across the province were infested by C. fagi. c) There was a positive correlation between pest abundance and tree diameter. d) A negative correlation was found between infestation rate and forest altitude. e) In northern slopes, pest abundance was higher than southern slopes and the other sunlit areas. f) The most sever infestation were observed on north side of trees trunks. According to the results obtained, it seems that light and moisture have a major role on pest abundance. Therefore sound sylvicultural practices based on modern forestry science account as an important procedure to control this pest. Meanwhile identification and protection of natural enemies play an important role in alleviating pest damages.