Studies On Bioecology And Management Of The Dendroctonus Valens

The red turpentine beetles (Dendroctonus valens Leconte-RTB) is a forest pest firstly detected in 1998 in Shanxi Province in china. Since then, this exotic pest has spread rapidly from Shanxi Province to three other adjacent provinces ( Hebei , Henan and Shaanxi ) and caused severe mortality. At present, 25000 ha, 29.1% of total pine forest has been damaged in Shaanxi. To control the pest, its biology and ecology need to be studied. Based on the -observations in field and laboratory, its biology, ecology and management are studied in this project.The results show that the damage varies in different environments, including soil condition, canopy density, growth and slope ocation of tree. Trees along roadside are most seriously damaged, and trees at the peak are more seriously damaged than in inner forest, the trees on the north side of the hill were damaged more severe than on the south side, trees of . the low canopy density were invaded more than that of the high canopy density. Temperature and humidity also affect the activity of the red turpentine beetles.The insects occur one generation a year but some occur three generations in two years with generation overlapping in Huanglong forestry and Leisizhuang forestry. Imago, larva, pupa all overwinter inside roots of trees. The flying summit of overwintered adult appears from middle April to the end of May and the peak period of their egg hatching is in the middle June to the first ten days of July. Most overwintered elder larvae bore stick in the first ten days of May, and then the adults began to emerge in the first ten days of July, but most adults emerge from middle August to September, The life of adult is 60 to 90 days, egg 10 to 11 days, larva 70 to 90 days and pupae is 12 days.To investigate its behavior, baited woods and pheromone were used to attract the red turpentine beetle. The result showed standing timber fumigation, trunk injection of pesticide, low capacity spraying and separating control were effective methods to control the red turpentine beetles in the forest, among which standing timber fumigation and trunk injection of pesticide are significantly effective, and 90 percent beetles were killed.We proposed, based on the above results, a practical way to manage this beetle.