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Chinese Agricultural Science Bulletin ›› 2019, Vol. 35 ›› Issue (19): 91-96.doi: 10.11924/j.issn.1000-6850.casb18020071

Special Issue: 水稻 农业气象

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Effects of Continuous Cloudy and Rainy Days on the Occurrence of Rice Blast in the Middle and Late Stages of Rice Grouting

  

  • Received:2018-02-23 Revised:2018-12-04 Accepted:2018-12-10 Online:2019-07-08 Published:2019-07-08

Abstract: To clarify the effect of continuous rain weather on rice blast in the middle and late stages of rice grouting, the correlations of meteorological conditions and the occurrence of rice blast in October of 2011-2016 years were analyzed. In this study, the disease index of rice blast in the middle and late stage of rice filling was positively correlated with the average low temperature in October, the correlation coefficient was 0.929, and the relationship was very significant. There was a positive correlation between the disease index of rice blast and the number of days over 90% of relative humidity, the correlation coefficient was 0.883, and the relationship was significant. There was a positive correlation between the disease index of rice blast and monthly rainfall and rainy days, the correlation coefficients were 0.761 and 0.671. And the disease index was negatively correlated with sunshine hours, the correlation coefficient was -0.775. The influence of continuous rainy weather and higher average low temperature on the rice blast in the untreated area in October was more important than the effect on the two fungicides control area. And the influence on the rice blast in two fungicides control area was the aggravation of branch plague and grain blast, the influence of the rice blast in the unused area was the aggravation of the panicle and neck blast. It had great influence on the occurrence of rice blast in susceptible varieties, and had little influence on the varieties of medium resistant varieties. Therefore, we suggest that farmers use fungicides with different mechanisms of action to respray on rice once more before the arrival of continuous and rainy weather. That would have a certain inhibitory effect on rice blast, and could be reduced the proportion of brown grain, improved rice appearance.