The morphology and differential variation of Dauerlarvae (LIV) of Bursaphelenchus xylophilus and B. mucronatus.

The morphology and differential variations of Bursaphelenchus xylophilus and B.mucronatus dauerlarvae in Ningbo of Zhejiang Province were investigated.The results showed that the dauerlarvae of both the Bursaphelenchus xylophilus and B.mucronatus carried by Monochamus alternatus had the same morphological characteristics,and the dauerlarvae coming from the same origin could develop and become either Bursaphelenchus xylophilus or B.mucronatus.The differential variation was affected by hosts and other environmental factors.It was found that the LIV with distinct mucro often turned into Bursaphelenchus xylophilus when leaving Monochamus alternatus and entering into Pinus thunbergii without distinct mucro or turned into Bursaphelenchus mucronatus with distinct mucro when entering into Pinus massoniana.