樟子松枯梢病流行因素及季节流行动态

通过樟子松桔梢病调查和病害流行相关性分析的结果，明确了樟子松桔梢病的发生与寄主和环境条件的关系，确定了病害发生的主要影响因子：即寄主感病性、林龄、造林密度、坡向、坡位及林位。结果表明：樟子松易感病，林龄大发病重，阳坡比阴坡发病重，密度大的比密度小的发病重，上坡、中坡、下坡发病程度由重到轻。林缘比林内重。随着平均温度、相对湿度和降雨量的增加，孢子飞散量增加。种子不带菌，该病的传播与种子无关。将2000年和2002年生长季节樟子松桔梢病病情逐月调查的数据，分别进行指数、韦布尔和理查德3种曲线的非线性回归分析，结果病情随时间的进展曲线以韦布尔曲线为最优。同时，也说明了樟子松枯梢病属于多循环的复利病害，因此，在病害预测和防治上也应采取相应的策略和方法。

The Epidemic Factors of Shoot Blight for Pinus sylvestris var. Mongolica and Seasonal Epidemic Dynamics

Through investigation of shoot-blight for Pinus sylvestris var. mongolica and correlation analysis of epidemic factors, we made clear the relationship between the disease, hosts and circumstances. The main influencing factors were determined, including host susceptibility, stand age, afforestation density, slope orientation, slope location. and different positions in a stand, Results show that Pinus sylvestris var. mongolica was prone to this disease attack. Regarding the state of disease of stands, it was getting more serous in old stands, big planting-density stands and the stands at sunny slope, compared to young stands, stands with small planting-density, and stands at shady slope, the occurrence of this disease was gradually lightening from upper slope to lower slope, and the situation in the edge of a stand was worsen compared to that inside the stand. Amount of spores flying upward increased with the increase of average temperature, relative humidity and rainfall. Seeds did not carry germs. The propagation of this disease has nothing to do with seed. By nonlinear regression analysis, Exponential, Weibull and Richards models were tested for appropriatness with the successive data observed monthly in the fixed plots of Shangzhi in growing season in 2000 and 2002. Results also indicated that the Weibull growth model was superior in describing the temporal dynamics of shoot-blight for Pinus sylvestris var. mongolica, which was a compound interest disease caused by polycyclic pathogen. So appropriate measures and tactics should be taken in respect to disease forecast and control.