The Japanese pine sawyer (JPS), Monochamus alternatus Hope, is an important vector of the pine wood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer), which causes pine wilt disease. JPS selects a characteristic life cycle of a four- or five-instar pathway, which indicates the number of instars before pupation. In this study, we investigated the potential presence of a three-instar pathway and sought to determine the minimum larval age required for JPS to construct a pupal chamber. The results showed that no third instars made pupal chambers, suggesting that there is no three-instar pathway. The initiation time of digging the tunnel to make the pupal chamber ranged widely from Julian date 274 (30 September) to 332 (27 November). This timing became an average age stage of 4.8 instar, which equals an 80% completion of the fourth instar. Thus, the minimum larval age at which JPS constructs the tunnel to pupate the next year is estimated to be late in the fourth larval instar. Further, we discuss the diapause ecology in relation to the larval development of JPS in different thermal environments. Tentatively, we suggest that the regulation of diapause induction in JPS involves a dual process of reaching a critical developmental stage and stimulus (tentatively a cold temperature). This hypothesis will be helpful for future studies of diapause mechanisms and the selection of the instar-pathway in JPS and related species.

Pine wilt disease (PWD) is one of the most important forest tree diseases, especially in the East Asian countries of Japan, China, and Korea. The Japanese pine sawyer, Monochamus alternatus Hope, is the PWN vector for Japanese red pine and Japanese black pine while Monochamus saltuarius Gebler is the vector for Korean white pine. Various control methods, such as aerial pesticide applications, biological control using parasitoids and fumigant such as methyl bromide are used. But the PWD still has spread. Therefore, we were selected effective aerial insecticides. Susceptibility of M. saltuarius and M. alternatus adults were investigated using 9 insecticides which are available in the market in Korea. And then, we tested them to the Apis mellifera to vertify the environmental impact.

Pine wilt disease, caused by pine wood nematode, Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle, has become the most serious threat to pine trees in Korea since first reported in 1988. Pine wood nematode is transferred to uninfested trees by Monochamus alternatus (Coleoptera: Cerambycidae) (vector). A typical controlling method against vectors in Korea is fumigation of the dead trees infested by vector M.alternatus and B.xylophilus using metam-sodium SL(25%). However, this method is harmful to the environment because of the chemical contamination and vinyl waste in the mountain afterward. Portable Bark Remover (PBR) was contrived to reduce these environmental problems. The vectors oviposite under the bark of the freshly dead trees only. Debark infested trees prohibited the vectors from oviposite and finally, vectors can not complete their life cycle. The PBR is a newly designed as a debarking device that is equipped on top of the chain saw engine allowing ease and rapid debarking of the infested trees at the controlling field. Debarking of freshly-dead trees can eliminate egg-laying and hatch places where between the wood and bark from vectors. The new method for vector controlling using the debarking device is expected to lower-price and high-efficiency comparing with other conventional methods such as “crushing”, “burning” and “fumigation”.