摘要
测定了世高等7种杀菌剂对棉花红腐病菌的室内毒力,在此基础上进行了复配剂的筛选。结果表明,施保克对棉红腐病菌的毒力最强,EC50为0.0923 mg.L-1;三唑酮、世高、丙环唑、阿米西达毒力依次减弱,代森锰锌的毒力最小。施保克分别与世高、三唑酮、代森锰锌、丙环唑、多菌灵,世高与代森锰锌复配等组合的EC50值均大于单剂或其中之一的EC50值,CTC值均低于50,表现明显的拮抗作用;世高与多菌灵按2∶1,1∶1,1∶2,1∶3,1∶5配比复配对病菌的EC50值范围为0.9742-1.4938 mg.L-1,平均为1.2247 mg.L-1;CTC1∶1>CTC1∶3>CTC1∶2>CTC2∶1>CTC1∶5,表明各配比均有显著的增效作用,其中1∶1配比的EC50值为0.8509 mg.L-1,明显低于单剂的EC50值,CTC为286,增效作用最大。综合经济效益和增效作用两方面考虑,1∶3配比最佳。
Cotton red rot is an important disease of cotton in China. The disease seriously endangers cotton by causing the rot of buds, stem bases and roots of cotton at seedling stage, and resulting in boll rot in boll phase. Recently, the incidence and severity of the disease at both seedling and boll stages have been developing with the extending of the Bt-transgenic cotton in Anhui, China. To screen the effective fungicides for the control of the disease, EC50 of seven kinds of fungicides and the co-toxicity of their mixed preparations to Fusariurn moniliforme Sheld, the pathogen of cotton red rot, were tested by means of mycelium growth rate method under the condition of laboratory, respectively. The results showed that EC50 values of prochloraz, triadimefon, difenoeonazole, propiconazol and carbendazin were 0. 0923, 1. 5604, 1. 7414, 2. 0602 and 2. 7599 mg · L^-1 , respectively, suggesting that the five fungicides tested all had good inhibition against the fungus. But azoxystrohin and maneozeb were not obviously inhibitory against the pathogen, with the EC50 value being 116. 0600 and 521. 0000 mg· L^-1 , respectively. On the basis of the experiments, the combined toxicity coefficients （CTC） and the synergistic effects of the mixtures of the five fungicides were investigated applying Sun ＆ Johnson method, and the results indicated that the mixtures of difenoconazole and carbendazin had all significantly synergistic effect while the other mixtures had not. CTC values of the mixtures with the mixing ratio of difenoconazole to carbendazin as 2 ： 1, 1 ： 1, 1 ： 2, 1 ： 3 and 1 ： 5 were 151, 219, 154, 208 and 140, respectively. The order of CTC values of the mixtures of difenoconazole and carbendazin with different mixing ratios of difenoconazole to carbendazin was CTC1： 1 〉 CTC1： 3 ？ CT1： 2〉 CTC2：3〉 CTC1：5. Among the five matching ratios, 1 ： 1 matching ratio of difenoconazole and carbendazin had the best additive effect. However, since the cost of difenoconazole is much higher than that of carbendazin, the optimal matching ratio of difenoconazole and carbendazin was 1 ： 3, considering both the synergistic effect and the economic benefits. In addition, it was observed that the mixtures of prochloraz and other fungicides tested and the mixture of difenoconazole and mancozeb had all obviously reductive effect on inhibiting the pathogen. Although azoxystrobin had evident inhibition against Fusarium rnonili.forme at the low concentration of 1 mg · L^-1 , the inhibitive effectiveness did not increase with the rise of concentration of azoxystrobin, and there was no significant difference in the inhibitive effectiveness of the tested concentration treatments from 1 to 200 mg · L^-1. The reasons are worthwhile to probe further. The results mentioned above provide experimental evidence for the exploitation of new and effective fungicides or mixed preparations and for the reasonable application of the chemicals to control cotton red rot.
出处
《棉花学报》
CSCD
北大核心
2007年第2期93-97,共5页
Cotton Science
基金
安徽省高校学科拔尖人才基金(200322)
安徽省"十五"科技攻关计划项目(01013011)资助
关键词
棉花
红腐病菌
杀菌剂
复配剂
联合毒力
增效作用
cotton
Fusarium moniliforme
fungicides
mixtures
co-toxicity
synergistic effect
