Transmission of Bursaphelenchus mucronatus Mamiya et Enda (Nematoda, Aphelenchoididae) from Monochamus saltuarius (Gebler) (Coleoptera, Cerambycidae) to pine branches via vector’s oviposition wounds in comparison to B. xylophilus (Steiner et Buhrer) Nickle carried by M. alternatus Hope

Abstract

ABSTRACT Non-pathogenic Bursaphelenchus mucronatus and pathogenic B. xylophilus are transmitted to pine trees by cerambycid beetles of the genus Monochamus. This study investigated the transmission of the two nematode species via vector’s oviposition wounds and their initial dispersal with relation to vector’s oviposition behavior and age for the B. mucronatus−Monochamus saltuarius and B. xylophilus−M. alternatus systems. M. saltuarius females were provided individually with a Pinus densiflora branch section. Immediately after the oviposition, branch sections were held at 25°C. The transmission of B. mucronatus was examined using the 15-mm-diam. bark disks containing an oviposition wound and their surrounding bark and xylem samples taken from branch sections 0 − 24 h after the oviposition. B. mucronatus was recovered only from the 15-mm-diam. bark disks. The proportion of oviposition wounds harboring B. mucronatus was 0.27 and the number of B. mucronatus transmitted into an oviposition wound averaged 2.1. When M. alternatus females were provided individually with a P. densiflora stem bolt, their oviposition behavior did not differ from M. saltuarius one. The inspection indicated that B. xylophilus was recovered from the 25-mm-diam. bark disks containing an oviposition wound and the surrounding bark and xylem samples taken from the bolts 0 − 24 h after the oviposition. The proportion of oviposition wounds harboring B. xylophilus was 0.31 and the number of B. xylophilus transmitted into an oviposition wound averaged 1.0. This study suggested that B. mucronatus left the vector’s oviposition wounds more slowly than B. xylophilus.