Abstract:Abstracts:By releasing Datarcus helophoroides on Bait trees,we compared and analyzed their parasitic rates on Monochamus alternatus and the economic cost of the three releasing methods using Datarcus helophoroides spawns,adults,spawns and adults.The results showed that from the perspective of the parasitic rates,the method using Datarcus helophoroides spawns was the best,the method using spawns and adults was at the second place,and the adult was the worse.From the view point of the economic cost,if achieving the same parasitic rate,the method using Datarcus helophoroides spawns was the best,the method using adults was at the second place,and the method using spawns and adults was the worse.Therefore, releasing Datarcus helophoroides spawns was the most effective and economical way,and the parasitic rate increased with the increasing of releasing spawns.When we released 3000 spawns,the parasitic rate on Monochamus alternatus was 64.52%.