樟子松枯梢病的侵染发生规律

Infection and occurrence regularity of Pinus sylvestris var. mongolica sphaeropsis blight

在辽宁省章古台 ,松枯梢病 Sphaeropsis sapinea主要发生在樟子松 Pinussylvestrisvar.mongolica苗木和中老龄树木上 ,树龄越大 ,病害越重。病菌孢子在整个生长季节均能放散与传播 ,降雨节律和降雨量直接影响到孢子的扩散期、高峰期和数量。降雨量大的年份 ,孢子放散数量多 ,病害发生重。人工接种树木发现 ,从新梢伸长至针叶发育完全期间 ,病菌无需伤口即可直接侵入当年新梢并使之枯萎。病菌的侵入时期主要在 5月下旬至 6月下旬 ,此间也是化学防治的最佳时期。野外自然条件下 ,病害自 7月份开始发生 ,8月中下旬发展最快 ,1 0月份停止。樟子松是最易感染松枯梢病的树种之一。

In Zhanggutai,Liaoning Province,the disease Sphaeropsis sapinea mainly infected the nursery seedlings and old trees of Pinus sylvestris var. mongolica .The old the trees,the more serious the disease.The spores of Sphaeropsis sapinea could spread throughout the growing season.The spread and amount of spores,however,depended largely on rainfall.In the years with larger rainfall more spores were spread and resulted in heavier infection.The inoculation showed during shoots elongating to full development of needles the fungus could penetrate unwounded young shoots,and made them dead.The infection occurred mainly from late May to late June in the field,in this period when fungicides should be applied if necessary.In plantation the disease occurred in July,developed fastest in mid and late August,and ceased in October. Pinus sylvestris var. mongolica was one of the most susceptible species to Sphaeropsis sapinea .