Abstract: Agrilus mali Matsumura causes a severe damage to the wild apple forests in the north Tianshan Mountains in Xinjiang since an invasion of insect pests from 1995.However,an assessment on the regional damage of insect pests is missed.In this study,the damage level of A.mali Matsumura and its impacts on the wild apple forests,fruit yield,old emergence hole density,etc.of wild apple trees in Xinyuan and Gongliu counties,where the wild apple trees grow widely,Xinjiang,were investigated.It was found that the damage of insect pests was the most serious in the Agricultural Improvement Farm in Xinyuan County,but it was the lightest in Jiaolesai,Second township and Damohe.There was a significant difference in the old emergence hole density because of the difference of A.mali Matsumura density and of fruit yield among seven sites.In apple orchards with the enhanced management,the infestation level was much lower.Therefore,it was suggested to extensively carry out the pruning at the sites with serious damage of insect pests.Insecticide spray by aircraft is thus recommended in the regions suitable for aircraft flight.Protected areas should be delimited and the pruning and bio-control programs could be applicable in the regions where local people cannot get easy access in the wild apple forests.

Key words: wild apple forest, Agrilus mali Matsumura, damage level, fruit yield, emergence hole density, north Tianshan Mountains, Xinjiang