Objective It is a sustained and long-term control effect that releasing of Dastarcus helophoroides to control Pine Wood Nematode disease by controlling Monochamus alternatus in the forest. In order to identify the key factors affecting the accumulation and rapid increase of the population of D. helophoroides in the forest, experiments were conducted in some epidemic areas in Jiangxi Province from 2020 to 2023, which only involved releasing D. helophoroides without cutting down or clearing infected trees.

Method Through comparative experiments on the parental source, body size, indoor breeding generations (activity), release ratio, and release frequency of D. helophoroides, it was investigated and analyzed that the impact of these factors on the increase of D. helophoroides population density in the forest.

Result The results showed that it was beneficial for the rapid accumulation of the population of D. helophoroides species in the forest that not cleaning the epidemic wood, while it was not conducive to the accumulation of the population of D. helophoroides species that using the method of cutting and burning the epidemic wood on site in the forest; Under the condition of not clearing the epidemic wood, the comprehensive application of these measures can significantly and rapidly increase the density of D. helophoroides populations in the forest that releasing the local source of D. helophoroides, releasing the parents with low indoor breeding generations (i.e., the highly active F3 generation), and releasing larger body individuals into the forest, with an artificial release ratio of 1:1 (the number of invasion holes of M. alternatus : the number of D. helophoroides adult), and releasing three times (i.e., releasing once every March for three consecutive years). These experiments can increase by 426.16% to 706.23% over a period of 4 years, which is 5.26 to 8.06 times higher than before no release.The comprehensive analysis of these factors shows that the treatment method of epidemic wood is the most important factor affecting the rapid increase of D. helophoroides in the forest.

Conclusion It can be seen that these are key factors affecting the accumulation and rapid increase of the population of D. helophoroides in the forest, that including the characteristics of the released D. helophoroides itself (including its parental source, body size, indoor breeding generations (activity)), artificial release techniques (including release time, release ratio, release frequency), and treatment methods of epidemic wood.This can provide scientific basis for the application of D. helophoroides in forestry production to prevent and control pine wilt disease by controlling M. alternatus.