Effect On The Inclusions Of Poplar Damaged By Apriona Germari (Hope)

Apriona germari(Hope) is an important trunk pest. With the characteristics of wide feeding habits and wide distribution, it is the main pest of many forest and fruit trees. A. germari is the new pest of poplar in Fujian. After damaged, poplar will become hollow tree, and even break in the wind. They seriously affect growth of poplar and its material quality. A. germari takes place one generation every two years in Fujian. Larvae become mature after feeding in the tunnel for about two years. From the last ten days of April to the first ten days of May, the mature larvae make emergence holes in the appropriate sites, then go back to the tunnel to build pupa cell and pupate. The pupal stage lasts about 25 days. After emergence, the adult stay in the tunnel for 2-3 days and go out in the last ten days of May. Ascending stage of emergence is from the last ten days of June to the first ten days of July. In this paper, inclusions of poplar are determined to demonstrate the effect of A. germari on inclusions of poplar. This will provide reference for selection and breeding of resistant poplar.The results indicate that secondary substances and nutrient substances in damaged poplar have significant change comparing with those in undamaged poplar. Contents of tannin and flavonoid increase, while contents of total phenols decrease. These may be the stress responses of poplar after damaged. Poplar may avoid pest's feeding by increasing the contents of tannin and flavonoid. The decreasing of total phenols content can condense synthesis of tannin. It can protect poplar from damaging by A. germari. Protein and carbohydrate are the important nutrient substances for the growth and development of insect. Content of protein, polysaccharide and soluble sugar in damaged poplar all decrease comparing with those in undamaged poplar. This may be due to the feeding of A. germari or due to the synthesis of other substances from protein and carbohydrate.At different damage stages of A. germari, contents of secondary substances and nutrient substances in damaged poplar are different from contents in undamaged poplar. During the damage initial and peak stage, content of tannin in damaged poplar decreases comparing with these in undamaged poplar. At terminal and over wintering stage, content of tannin in damaged poplar increase comparing with those in undamaged poplar. Content of flavonoid in damaged poplar increase at initial stage, terminal stage and over wintering stage, but decrease at peak stage. Content of total phenols in damaged poplar decrease in the whole damaged stage. In each damaged stage, content of protein in damaged poplar show significant difference comparing with these in undamaged poplar. Comparing with the undamaged poplar, content of protein in damaged poplar is higher at initial stage, peak stage and terminal stage, but lower at over wintering stage. Content of polysaccharide in damaged poplar is lower at initial stage, peak stage and terminal stage (especially at initial stage and peak stage). There exists greatly significant difference of polysaccharide content between damaged and undamaged poplar. At each damage stage, damage of A. germari results in extremely significant change of soluble sugar content. It decreases significantly at damage stages, but increase markedly at over wintering stage.Secondary substances and nutrient substances in different poplar varieties are different, and content changes are also different after damaged by A. germari. Comparing with European and American poplar, both of the damaged and undamaged Italian poplars have higher contents of tannin, flavonoid, total phenols and soluble sugar. Contents of polysaccharide and protein in damaged Italian poplar are lower than these in damaged European and American poplar. This illustrates that Italian poplar may defend A. germari by increasing secondary substances, and improve its resistance by decreasing nutrient substances.Contents of secondary substances and nutrient substances in poplar damaged by A. germari have relationship with distance to the damaged sites. The results suggest that, contents of tannin and flavonoid far away from the bore hole have no significant difference in damaged poplar. However, in damaged poplar, contents of total phenols, protein, polysaccharide and soluble sugar far away from the bore hole show extremely significant difference, the nearer to the damage sites, the lower they are.