江西省晚粳品种对稻曲病的抗性评价及稻曲病药剂防治技术研究

为筛选适宜江西省种植的抗稻曲病晚粳品种和稻曲病防治药剂及其使用技术,采用自然诱发法鉴定了27个晚粳品种对稻曲病的抗性,采用菌丝生长速率法测定了10种药剂对稻曲病菌的室内毒力,并试验了其田间防效。田间鉴定结果表明:在27个粳稻品种中,按病穗率作抗性评价指标,高抗品种3个,抗性品种14个,中抗品种7个,中感品种3个。室内毒力测定结果表明:10种杀菌剂抑制稻曲病菌丝生长的相对毒力指数顺序为腈苯唑(168.49)噻呋酰胺(111.08)嘧菌酯(107.84)氟环唑(91.68)苯醚甲环唑·丙环唑(83.47)戊唑醇(42.34)咪鲜胺(21.51)己唑醇(12.92)三唑酮(1.32)井冈霉素(1)。田间试验结果表明:24%噻呋酰胺SC、24%腈苯唑SC、12.5%氟环唑SC和25%嘧菌酯SC对稻曲病具有较好的防效,其次为300 g/L苯醚甲环唑·丙环唑EC和43%戊唑醇SC,其他4种药剂防效相对较差。在水稻破口前7天施药优于在水稻破口期和破口后7天施药,增加施药次数可提高药剂防治效果。本研究结果为江西省晚粳抗稻曲病品种的选育应用和稻曲病药剂防治提供了依据。

Resistance Evaluation of Late Japonica Rice Varieties Against Rice False Smut in Jiangxi Province and Chemical Control Technology

To screen resistance varieties of late japonica rice with resistance to rice false smut, which are suitable for planting in Jiangxi Province, and fungicides against rice false smut and their application technologies, the resistance of 27 varieties of late japonica rice to rice false smut was identified by natural infection, indoor toxicities of 10 fungicides against rice false smut were assayed by measuring mycelial growth rate, and their efficacies were tested by field trials. Field identification results showed that there were 3 high resistance varieties, 14 resistance varieties, 7 middle resistance varieties, and 3 middle susceptible varieties among the 27 varieties of late japonica rice according to disease panicle rate for resistance evaluation index. Bioassay results showed that the relative toxicity index of the 10 fungicides in inhibiting mycelium growth of rice false smut had an order as fenbuconazole (168.49) > thifluzamide (111.08) > azoxystrobin (107.84) >epoxiconazole (91.68) > difenoconazole · propiconazole (83.47) > tebuconazole (42.34) > prochloraz (21.51)>hexaconazole (12.92)>triadimefon (1.32)>jinggangmycin A (1). The field test revealed that 24%thifluzamide SC, 24%fenbuconazole SC, 12.5%epoxiconazole SC and 25%azoxystrobin SC had better efficacy against rice false smut, followed by 300 g/L difenoconazole · propiconazole EC and 43%tebuconazole SC. The efficacy of the other four fungicides was relatively poor. The efficacy of treatment with spray 7 d before heading was better than that with spray in heading and 7 d after heading. The efficacy of fungicides against rice false smut was improved with the increase of spray times. The result of this study provided a basis for the breeding and application of resistance varieties of late japonica rice in Jiangxi Province and chemical control against rice false smut.