落叶松枯梢病检疫技术的研究

Study of Quarantine Techniques for Larch Shoot Dieback

据调查,落叶松枯梢病在国内8个省(区)110个县(市)有分布。种子、无症状的苗木,新梢及2年生以上的枝干树皮、木质部均不带病原菌,仅病苗、病梢是带菌者。离体病原孢子在自然条件下只能存活13d,组织内部的菌体可存活3～4a。故落叶松苗木、接穗、原木、小径木为应受检疫对象。以现场抽样观察与病理解剖为主,必要时辅以诱发试验、分离培养是可靠的检验手段。清除混杂在苗木中的罹病个体和原木、小径木上附带的小枝梢是简便、易行、有效的除害处理方法。

On the basis of the investigation of larch shoot dieback, it was showed that the disease is distributed in 8 provinces (districts) and HO counties (cities), according to the distribution map of epidemic area. No pathogen was discovered on seeds, seedlings, healthy fresh shoots, or branches, trunks, bark and xylem of the larch over two years old. The infected seedlings and shoots are carriers. Under natural condition, the pathogen spores can only be alive for 13 days after it was separated from the host. However, the pathogen within the host tissues can be alive 3~4 years, therefore the seedlings, scions, logs and small diameter logs should be quarantined. The sample inspection and anatomy are major measures for the quarantine, aidded by germination and isolation tests if necessary. To clear up the infected individual seedlings or/and the infected shoots of the log are the simple, easy and effective methods.