چرخه زيستي و نحوه خسارت كنه تاولي گلابي در غرب ايران

Study on biology and damage of the pear leaf blister mite (Phytoptus pyri) in western Iran

There are different phythophagous mites on pear trees in western Iran. Amongst them the pear leaf blister mite (Phytoptes pyri Pagenstecher) is the most serious pest. However, the influence of the prevailing climatologically conditions of western Iran on this species are unknown. Surveys were conducted during 2002 – 2003. It causes pinkish-red pustules on young leaves during spring. They subsequently turn yellow, red or green, occurring on both sides of infested leaves. They can be scattered randomly over the leaves, or in bands on each side of the midrib. About 22% of the leave surfaces become chlorotic and adult mites keep on migrating to new pastures. Eventually the blisters turn brown then black and then the leaves fall off. The fruit of severally infested trees can be malformed and also fall off, especially in urban areas (gardens). The infestation reaches its peak in the middle of September (end of Summer). In some regions it can cause 100% defoliation and loss of fruit, in these cases it affects the fruit production of the following year. During late Summer, early fall (last half of September) adult mites seek cover under bud scales where they over winter to re-appear again during Spring. This mite has 1-3 generation in a year.