Traumatic resin-canal formation caused by inoculation withCistella japonica in secondary phloem ofChamaecyparis obtusa

In the resinous lesion development caused by the inoculation withCistella japonica onChamaecyparis obtusa stem, numerous traumatic resin-canals were formed at certain radial intervals in the secondary phloem. These formation started in the ring grown in the current or the previous year of inoculation and the resin-canals were subsequently formed in the newly grown rings. The resin-canals were arranged in tangential series in one to two lines in an annual-ring. Artificially induced resin-canal formation was similar to that in naturally infected resinous stem canker. The results from the present study reconfirmed thatCi. japonica is the causal agent of the disease.