水稻生育期空气中稻曲病菌孢子释放动态及影响因素分析

【目的】明确稻曲病菌孢子在田间的释放动态及影响因素,为水稻稻曲病预测及防治提供科学依据。【方法】采用孢子捕捉仪对四川稻区稻曲病菌孢子释放量进行监测,分析稻曲病菌孢子在田间的释放动态;2014~2016年连续3年收集水稻生育期的气象数据,包括温度和平均湿度等,研究气象因子、孢子释放量与稻曲病的内在联系。【结果】在水稻生育期间稻曲病菌孢子释放量呈动态变化,5月中旬~7月上旬稻曲病菌分生孢子释放量逐渐上升,7月下旬空气中的分生孢子量骤然上升,7月末~8月上旬孢子量达到峰值,8月中旬后孢子量逐渐下降,9月下旬孢子量下降至接近5月的水平。自孢子释放达到高峰后10 d田间稻曲病开始显症。稻曲病菌孢子释放量与田间菌源及上年病害严重度呈一定的正相关,与温度和湿度亦具有一定相关性,当平均温度25.0~30.0℃、湿度大于85.0%时有利于稻曲菌孢子的释放,同时有利于稻曲病的发生。【结论】稻曲病菌孢子释放量、气象因子与稻曲病间存在密切联系。

Spore release dynamics of Ustilaginoidea virens(Cooke) Takahashi in the air and its influence factors at rice growth period

Objective]This experiment studied the spore release dynamics of Ustilaginoidea virens(Cooke)Taka-hashi in field and its influence factors in order to provide scientific reference for predicting occurrence of rice false smut.Method]The spore release of U. virens using the spore trap in Sichuan rice growing area were monitored,and spore release dynamics of U. virens in field were analyzed. Meteorological data during 2014-2016 at rice growth period were collected,including temperature and average humidity,to study the inner relation among meteorological factor,spore release and rice false smut.Result]It was found that the spores release exhibited dynamic change during rice growth period. Meanwhile,the results showed that the spores release rose gradually from middle May to early July,spore release boosted sharply in late July and reached the peak in late July and early August,then declined gradually from middle August. In late September,spore amount declined to the level in May. Symptom of rice false smut was visible after 10 d from the spore release peak. The spores release was positively correlated with the pathogen quantity in field and disease severity in the last year,and it also related to temperature and humidity. Conditions with average temperature being 25 to 30℃and relative humidity over 85%were advantageous to the spores release and the happening of rice false smut.Conclusion]There is close connection among spore release,meteorological factors and rice false smut.