Practical research for the establishment of the control system against the pine-wilt disease in the cool climate regions

为了建立防治体系，我们明确了寒冷气候地区松材萎蔫病的发生特点：日本北部秋田县全年发生松枯萎病病死，而温暖地区病死树木在夏季几乎全部死亡。2 . 6月中旬至7月下旬，观察到病媒松锯毛鼠（Monochamus alternatus endai）成虫羽化，产卵时间比羽化时间晚1个月左右。3 .在松树的茎上或枝上产卵较多，而在茎下产卵较少。温暖地区的松锯虫虽然为1个生命周期-1年，但其生命周期往往延长至2年周期，特别是在凉爽的夏季产卵。2年周期的松材锯材线虫传播量少，因此对2年周期的松材锯材的防治效果较差。在此基础上，提出了寒带地区松材萎蔫病防治新体系“秋田体系”。采用兼顾传病昆虫生态特性的防治方法对有效防治具有重要意义。在秋田系统中，处理的目标树仅限于有sawyer幼虫的夏弱树。该系统已被秋田地方政府采用，预计将对防止松材枯萎病的扩大产生良好的效果。此外，我们已经碳化损坏的树木，这有影响，损坏的树木可以转化为生物资源。这些活动引起了当地人的注意。当地居民、当地政府和科学家的合作对于保护松林免受松材枯萎病的侵害是不可或缺的。

To establish the control system, we have clarified the characteristics of the outbreak of pine-wilt disease in the cool climate regions as follows.1. The outbreaks of dead trees caused by pine-wilt disease occurred all the year round in Akita Prefecture, northern Japan, while almost all the infected trees in warm regions are dead in summer.2. Adult emergences of disease-spreading pine sawyer Monochamus alternatus endai were observed from the middle of June to the end of July, and the oviposition was about one month later than the emergence.3. The ovipositions of pine sawyers were more frequent in the upper stems or branches of pine trees than the base of the stems.4. Although the pine sawyers in the warm regions have 1 life cycle-1 year, their life cycle often elongated to 2 year-cycle, especially oviposited in the cool summer. The pine sawyers with 2 year-cycle conveyed much less nematode, so that much less attention should be paid to the 2-years cycle sawyers for the control.According to these results, we proposed the new control system, "Akita-system", against the pine-wilt disease for the cool climate regions. It is important to adopt to the method taking account for the ecological traits of disease-spreading insects for efficient prevention. In Akita-system, the target trees to be disposed were confined to summer-weakened trees with sawyer larvae. This system is adopted by Akita local government, and is expected to have a good effect to prevent the enlargement of pine-wilt disease. Furthermore, we have carbonized the damaged trees, which have the effects that the damaged trees can be converted into bioresources. These activities have called the attention of the local persons. Collaboration by the local person, local government and scientists is indispensable to the protection of the pine forests against the pine-wilt disease.