Objective Factors conducive to rapid rise and maintain the Dastarcus helophoroides population for a sustainable, long-term control of pine wood nematode disease in a forest were analyzed.

Method Experiments were conducted in nematode-infected areas in Jiangxi Province by releasing D. helophoroides without cutting down or clearing diseased trees were conducted from 2020 to 2023. Impacts of the body size and indoor breeding generations (activity) of D. helophoroides as well as the rate and frequency of the release on the insect density and disease control at the sites were monitored.

Result Both the increase rate and accumulation of D. helophoroides populations were significantly encouraged by not clearing the infected woods or cutting and burning the diseased trees at the sites. Thus, under the conditions, various D. helophoroides release measures were implemented. It was found that the release of the local species from parents with low indoor breeding generations (i.e., the highly active F3 generation) and large body at a rate of 1∶1 (i.e., number of nematode invasion holes on trees by Monochamus alternatus : number of D. helophoroides adults) once in March for 3 consecutive years significantly rose the insect density by 426.16%–706.23% in 4 years. The increase was 5.26 to 8.06 times higher than without the release.

Conclusion The experimented method significantly increased D. helophoroides population at the sites. The application conditions included, in addition to not clearing, cutting, or burning the diseased trees at the sites, releasing the local D. helophoroides of specific parental source, body size, and indoor breeding generations (activity) at the specified time, rate, and frequency. The implementation significantly accelerated the increase of the insect population and effectively helped control the pine wilt disease spread by M. alternatus infestation in the forest.