1为害症状主要以若虫刺吸叶片汁液为害,也可为害果实。成虫亦可为害,但不严重。若虫多在叶片背面为害,常分泌黏液将2片或几片叶粘在一起。叶片受害后叶脉扭曲,叶面皱缩,产生黑斑,严重时叶片变黑,提早脱落。为害果实的若虫分泌黏液,使果实表面出现霉污。2发生规律梨木虱在全国各 1 damage to the main symptoms of nymphs sucking leaves juice damage, but also harmful fruit. Adults can also be harmful, but not serious. Nymphs more damage on the back of leaves, often mucus will be secreted 2 or a few leaves stick together. Leaf damage after the veins twisted, leaf folds, resulting in dark spots, severe black leaves, early off. Fruit nymphs secrete mucus, so that the surface of the fruit moldy. 2 occurs law pear psylla in the country each