粒肩天牛危害对杨树单宁含量的影响

粒肩天牛是福建省杨树的一种新蛀干性害虫，经对杨树受害与未受害、不同危害期、不同品系、不同危害部位单宁含量测定。结果表明：受害植株与健康植株间单宁含量差异显著；不同危害期单宁含量差异极显著，在天牛危害末期和越冬期，受害植株单宁的含量比健康植株增加；不同杨树品种单宁含量变化不同，意大利杨健康植株和受害植株的单宁含量均比欧关杨高；受害植株中远离蛀孔与蛀孔周边的单宁含量未表现出显著差异。杨树受害引起单宁含量的变化，可能是杨树受到危害后的一种应激反应的表现，具有诱导抗虫性，即通过增加单宁的含量来抵御害虫的取食。

Effects of Apriona germari Hope damage on the contents of tannin in poplar

Apriona germari Hope is a new pest appeared recently who damages of poplar in Fujian. By means of testing the contents of tannin in poplar of damaged and undamaged,different damaged stages, different poplar strains and damaged sites, it indicates that： tannin in damaged poplar have significant change comparing with undamaged poplar, but contents of tannin far away from the bore hole have no significant difference in damaged poplar;at different damage stages of A. germari,tannin in damaged poplar are differ- ent from contents in undamaged poplar, at terminal and over wintering stage, content of tannin in damaged poplar increase comparing with those in undamaged poplar; that a significant difference in tannin content was found in different poplar strains, comparing with European and American poplar,both of the damaged and undamaged Italian poplars have higher contents of tannin. It is thought that poplar damage and the tannin contents increase is related to poplars induced resistance to the pest.