Abstract:

The bark beetle, Dendroctonus valens LeConte, infested mainly pine tree over 30-year-old. It has been a disaster of pine forest in Shanxi province and part areas of Hebei and Henan provinces since 1998. This research reported the results of infectivity of 7 species belonged to Steinernema and Heterorhabditis to matural larvae of the bark beetle Dendroctonus valens LeConte in laboratory. Steinernema ceratophorum, isolated from Jilin province in Northeast China, was the best nematode species for infection of the pest larvae among the 7 species of nematodes. The mortality of insect larvae reached to 90% after exposure to nematode for 96 hours. The LC₅₀ based on 3 day insect mortality was 24±4.2 infective juveniles. Other nematode species tested in this trial were not sensitive to the larvae of Dendroctonus valens. Each host cadaver could produce 6770 infective juveniles. These new generation nematodes would provide nematode resource to infect healthy insect larvae living in bark during field application. This result would be helpful for finding a new way to the integrated control of the bark beetle Dendroctonus valens.

Key words: Dendroctonus valens, Steinernema ceratophorum, Infectivity