水稻穗腐病病菌致病性、发生规律及防控技术研究

Occurrence,epidemical regularity and controlling of rice spikelet rot disease(RSRD) and pathogenicity of its pathogens

穗腐病是近年发生危害严重的水稻穗部病害。本研究对穗腐病的发生、流行原因进行了分析,分离了病原菌并测定了致病性,筛选了防治该病的杀菌剂并进行了田间防效试验。结果表明,紧穗型的粳稻及籼/粳杂交稻组合较穗型松散的籼稻及其杂交组合更易感病。水稻孕穗后期-抽穗扬花期遇阴雨高湿、温暖天气该病发生危害重。用分离到的4个菌(层出镰刀菌、澳大利亚平脐蠕孢菌、新月弯孢菌和细交链孢菌)进行人工接种,均能使稻粒感病,初步确定层出镰刀菌为主要初侵染菌。室内抑菌测试结果显示,5mg/L以上浓度的多菌灵、咪鲜胺和苯醚甲环唑.丙环唑(爱苗)对层出镰刀菌生长的抑制效果达到81.31%～100%。抑制中浓度为0.000 7～0.947 6mg/L。田间试验结果表明,在水稻孕穗后期和抽穗扬花期用三唑酮、多菌灵或甲基硫菌灵喷雾防治一次,防效在70%左右。

In recent years, rice spikelet rot disease （RSRD）, which infects rice panicle, occurred in rice producing regions all over the country. In this research, occurrence and epidemic regularity of RSRD and pathogenicity of its pathogens were investigated, and control efficacies of several fungicides were evaluated by field test. Combination of Japonica rice with tight panicles and Indica / Japonica Hybrids was more susceptible than that of Japonica rice with disperse panicles and its hybrids. The relation of weather conditions and occurrence showed that RSRD became serious and caused lots of yield losses when rainy or hot weather condition occurred in late booting to flowering stage of rice. Four pathogens, Fusarium proliferaturn, Bipolaris australiensis, Curvularia lunata, and Alternaria tenuis could infect the rice grains, and Fusarium proliferaturn was identified to be the main preliminary pathogen. Inhibition test indoors showed that inhibition rate of difenoconazole . propiconazole （Armure） EC, prochloraz and carbendazim to F. proliferaturn reached 81.31%-100% at the concentration of above 5mg/ L, and the EC50 values of the three fungicides were 0. 9476 to 0. 0007 mg/L. Field test indicated that the control efficiency could reach about 70% after spraying triadimefon, carbendazim or thiophanate-methyl once in late booting stage and flowering stage, respectively.