萧氏松茎象幼虫食性、危害及防治技术

萧氏松茎象幼虫在南岳衡山主要危害华山松，在寄主树干基部皮层和裸露的根皮层蛀食，造成大量流脂，导致生长衰弱，引起松墨天牛暴发；同时取食新鲜松脂，越冬后的幼虫仅靠取食新鲜松脂就能正常发育。幼虫只危害健康松树，不危害衰弱木、枯立木，说明其蛀食危害与松树能否分泌松脂有关。在被害松林内，单株幼虫数在0～6头之间。幼虫在有虫株之问分布较均匀，1头／株的占82．5％，平均为1．38头／株，且单株虫口密度与树干基部直径呈明显正相关。混交林和非松树林分能阻止该虫扩散。5—10月间在幼虫危害期和蛹期，采用人工清除幼虫和蛹的方法可有效控制该虫危害，而采用化学药剂防治该幼虫，效果不明显。

Feeding habits,damage characters and control techniques of the larvae of Hylobitelus xiaoi

In Nanyue Mounts of Hunan Province, Hylobitelus xiaoi Zhang attacked mainly Pinus (armandi) with its larvae boring in the bark of base trunks and naked roots.The damage weakened the growth of the hosts resulting in the outbreak of Monochamus alternatus .Its larvae fed on fresh pine resin also and could grow and develop normally after overwintering,living on only the fresh resin.The larvae bored only in healthy pines and this (indicated) that its feeding was related to the secretion of pine-resin.There were 0-6 larvae per tree in the infested stands and their distribution among the infested trees was even.One larva per tree occupied 82.5% of the infested trees with the average of 1.38 larvae per tree.The number of larvae per pine was positively correlated with the diameter of the base trunks of the hosts.Mixed forests and non-pine forests can prevent this pest from spreading.During the larvae stage and the pupa stage,clearing away the larvae and pupae artificially could effectively control the pest while chemical control achieved little effect.