Testing the host range of Cyanopterus ninghais (Hymenoptera: Braconidae), a candidate for the biological control of Monochamus alternatus, the vector of pine wilt disease in Asia

Abstract

Monochamus alternatus is a serious wood borer of pine trees and is a widespread vector of pine wilt disease in Asia. Cyanopterus ninghais, as a biological control agent of M. alternatus found in China, is expected to be applied for management of M. alternatus in Asia through introduction or augmentative release. To examine the host range of C. ninghais and minimize potential risk to non-target hosts in the release areas, the parasitism of this wasp on 22 species of wood boring insects from pine and other forests was determined by non-choice tests. Cyanopterus ninghais parasitized Spondylis buprestoides and M. saltuarius which also infested trees in Pinaceae, but the parasitism rates on these two beetles were significantly lower than its natural host, M. alternatus. Cyanopterus ninghais always preferred to parasitize M. alternatus in the choice tests. In addition, host plant selection tests revealed that C. ninghais was only attracted to Pinaceae, especially Masson Pine, Pinus massoniana. Changing the host plant species did not affect the preference of this parasitoid to the test hosts. The results suggested that C. ninghais had high host specificity for M. alternatus, and the combination of M. alternatus larvae and Masson Pine branches was the best combination for rearing this parasitoid.