Evaluation of Resistance of Asian Pear (Pyrus serotina Rehd.) Cultivars to Pear Lace Bug (Stephanitis pyri F.) and Investigate the Population Flactuations of the Pest under Environmental Conditions of Tehran

This project was conducted in 2008 growing season in order to explore and evaluate the resistance of some Asian pear (Pyrus serotina Rehd.) cultivars including " KS6 ", " KS7 ", "KS8", "KS9", "KS10", "KS11", "KS12", "KS13" and "KS14" to pear lace bug (Stephanitis-pyri F.). Evaluation of insect resistance were determined based on the number of insects on leaves, leaf damage rate, total fruit yield, amount of fruit loss, relative water content and leaf chlorophyll content. KS8 and KS14 cultivars with a few numbers of pear lace bug and lower leaf damage rate, KS6 and KS13 with the highest fruit yield and higher chlorophyll content, were found to be moderately resistant to the lace bug of the antixenosis and tolerance types, respectively. Assessed correlation of relative water content and resistance components, indicated positive correlations among them.