球毛壳菌对樟子松的侵染规律研究

榆林风沙区樟子松枯死主要发生在10—15年生幼龄林上，7月上旬至8月下旬为感病高峰期，翌年4月中旬至5月中旬为死亡高峰期。病菌孢子在整个生长季均能放散与传播，降雨节律及降雨量直接影响孢子的扩散与数量。人工接种发现：病菌的侵入期主要在6月中旬至8月中旬，潜育期半个月，侵入途径是伤口，病株感病部位及枯死枝是病原菌的越冬场所，密度高，植被盖度大的林分感病重。

The Rule of Evolution for Pinus sylvestris L. var monglica Litv Infected by Chaetomium globosum Kunnze

The wilt of Pinus sylvestris L. var mongolica Litv in Yulin sandy area mainly took place in the younger forest with 10 to 15 years old. The peak period of infection was from the earlier of July to the later of August each year. The peak period of death of tree was middle of April to middle of May in the next year. It were possible to be released and transfered for sporule of the disease during the whole growing period. The frequency and quantity of rainfall directly influenced the transfer and amount of the sporule. Artificial inoculation showed that the time of infection for disease was mainly from middle of June to middle of August, the period of the latency for disease is half month, the way to invade for the disease was through the injured part of tree, the infected part of a tree and dead twig were the places, where the pathogenic fungus lived inwinter and it were easy to be infected for those forest with high density and high coverage.