Meteorological Forecast Model Of Rice Blast Occurrence Potential In Jiangxi Province

Rice pests and disease are the major restrict factors of rice yield and quality, and rice blast is one of the important rice diseases that always lead to serious yield lose and even no production in Jiangxi Province, for its paroxysmal, eruptive and harmful characteristics. Rice blast was affected by meteorological factors obviously. Based on rice blast observations and meteorology data from some counties in Jiangxi, the characteristics of double season rice’s seeding, leaf and neck blast were analyzed in this paper, and the relationships between the disease and meteorology conditions were studied, found on which the meteorological forecast models of double season rice blast were established. The main conclusions are as follows:(1)Rice blast in Jiangxi had characteristics of "mountainous area severer than hill area, hill area severer than plain area, Southern and middle area in Jiangxi severer than Northern area, early rice severer than late rice". Since1970s, rice blast had been rose to frequently happened disease of rice in Jiangxi province, and the disaster loss of this disease increase obviously from2000. The server disease with a maximum frequency occurred in early rice neck period and with a minimum frequency in early and late rice seeding period. For early rice, the rice blast peak periods in southern Jiangxi were earlier than in northern and middle Jiangxi. For late rice, the rice blast peak periods in northern and middle Jiangxi were earlier than in southern Jiangxi.(2) The suitable temperature, abundant rainfall and high moisture was very suitable condition for rice blast in Jiangxi. Higher temperature area and lower sunshine area in early rice season were consistent with early rice blast server area; lower temperature area, richer rainfall area and lower sunshine area in late rice season were consistent with late rice blast server area.(3) Because of the distinct occurrence period and environment, the disease showed different relationship with meteorological factors. The temperature was positive correlated to early rice seeding blast, uncorrelated to late rice neck blast, and negative correlated to rice blast in other type. Precipitation was negative correlated to early rice leaf blast, uncorrelated to late rice neck blast, and positive correlated to rice blast in other type. Moisture was negative correlated to early rice seeding blast, uncorrelated to late rice seeding blast, and positive correlated to rice blast in other type. Sunshine hours was positive correlated to early rice seeding blast, uncorrelated to late rice neck blast, and negative correlated to rice blast in other type.(4) Based on temperature, precipitation, sunshine hours and moisture anomaly, the rice blast in different type occurrence potential meteorology forecast model was established. Model checking showed that, the accuracy rates were60%～75%. For all type rice blast diseases, the accuracy rates of severe disease were higher than light disease, which showed that the forecast model had better effect on severe disease than light disease.