【作者】 夏慧；

【导师】 陈厚德；

【作者基本信息】 扬州大学 ， 农业昆虫与害虫防治， 2004， 硕士

【摘要】 检测了江苏省13个市56个县（市）的160株小麦纹枯病菌（Rhizoctonia cerealis）、9个市16个县（市）的51株水稻纹枯病菌（R.solani）对井岗霉素的敏感性，并研究了影响病菌敏感性的营养、物理及化学等各种因子。 通过田间用药分离菌株与野生敏感菌株对井岗霉素的敏感性比较以及敏感性频率分布研究表明：江苏省小麦纹枯病菌对井岗霉素未产生抗药性，井岗霉素仍然是防治小麦纹枯病的高效、低毒、经济的主要药剂；水稻纹枯病菌中部分AG_1-1A菌株对井岗霉素已产生抗药性，田间出现了低抗、中抗菌株。禾谷丝核菌对井岗霉素的敏感性要高于立枯丝核菌；同时，两种丝核菌的不同菌丝融合群对药剂的敏感性也有差异。 通过以野生敏感菌株的敏感性(EC₅₀)与菌株敏感性频率分布图的方法来确立菌株敏感性基线，这两种方法确定的敏感性基线值略有不同，但差异不大。同时，按这两种方法进行稻、麦纹枯病菌对井岗霉素抗药性监测的结果相一致。因此认为，作菌株敏感性频率分布图的方法确立敏感性基线可能更为合适。 不同氮磷钾水平下稻、麦纹枯病菌对井岗霉素的敏感性不同。室内试验表明，增加氮含量，井岗霉素对稻、麦纹枯病菌的抑制率显著下降；增加钾含量，其抑制率显著增强。而磷含量的变化对药剂抑制率影响不大。盆栽试验表明，植株体内的不同营养元素含量对井岗霉素防治稻、麦纹枯病的效果有显著影响。增施氮肥或氮肥用量过多、植株体内含氮量高，纹枯病发生重，且井岗霉素对纹枯病的防效显著下降；增施钾肥、植株体内含钾量高，纹枯病发生轻，井岗霉素对纹枯病的防效显著增加；增施磷肥、植株体内含磷量的增加对防效的影响不显著。 温度、pH值、几种杀菌剂及除草剂的使用对井岗霉素抑制纹枯病菌的生长均有一定影响，尤其温度、pH值的影响最为显著。22℃时0.2μg/ml井岗霉素对小麦纹枯病菌的抑制率最高，与15℃、28℃时的药剂抑制率相比达显著差异；其次为扬州大学硕士学位论文28℃时的药剂抑制率，但与15℃时的相比差异不显著。在28℃时，0.2p岁ml井岗霉素对水稻纹枯病菌的抑制率最高，与21℃、35℃时的相比达显著差异;21℃与35℃时抑制率相比也不显著。pH7时井岗霉素对稻、麦纹枯病菌的抑制率最高，pHS时次之，但二者之间差异不显著;pHg时抑制率最低，并与pHS、7时的抑制率相比达显著差异。因此，在实验室进行菌株对药剂敏感性测定时，培养温度、培养基pH值的控制与稳定很重要。多菌灵、三哇酮、戊哇醇等杀菌剂及精恶哇禾草灵、氟草定、苯磺隆、乙草胺、丁草胺等除草剂均能抑制稻、麦纹枯病菌的生长;同时，它们对井岗霉素抑制纹枯病菌的效果产生促进作用，即稻、麦纹枯病菌经这些药剂处理后，随着处理浓度的增加，病菌对井岗霉素的敏感性则增强，而且水稻纹枯病菌的敏感性上升趋势要明显高于小麦纹枯病菌。更多还原

【Abstract】 160 isolates of Rhizoctonia cerealis causing sharp eye spot of wheat and 51 isolates of R. solani causing rice sheath blight collected respectively from 56 counties and 16 counties of Jiangsu Province, were detected for their sensitivity to Jinggangmycin and some nutritive, physical and chemical factors influencing the sensitivity were studied.By comparison of the sensitivity of tested isolates to Jinggangmycin with that of wild ones and the sensitivity frequency distribution of tested isolates, R. cerealis did not develop the resistance to Jinggangmycin, which showed that Jinggangmycin was still an effective agricultural antibiotic to control sharp eye spot of wheat caused by R. cerealis. But the low and moderate resistance of some isolates of R. solani AG1-I A to Jinggangmycin was found in the field. The sensitivity of R. cerealis to Jinggangmycin was higher than that of R. solani. There were some differences in the sensitivity to the antibiotic among anastomosis groups of two pathogens.EC50 of the wild sensitive isolate and the mean EC50 in the normal distribution of tested were used to determine the sensitive lines. There were little difference in two sensitive lines. It is considered that the method of sensitivity distribution of population was more suitable.The concentration of nitrogen and potassium in Czapek’s dox medium significantly affected the sensitivity of R. cerealis and R. solani to Jinggangmycin. The results showed that the higher concentration of nitrogen in the medium was the lower inhibition of Jinggangmycin to R. cerealis and R. solani and the higher concentration of potassium was, the higher inhibition. But the concentration of phosphorus in the medium had little influence on the inhibition of the antibiotic to two pathogenic fungi. The potted experiment indicated that the control effects of Jinggangmycin against sharp eye spot of wheat and rice sheath blight were significantly correlated to nitrogen and potassium contents of plants. The incidence of two diseases varied with nitrogen contents of plants, and higher nitrogen contents significantly reduced the control effects of Jinggangmycinagainst the diseases. While higher potassium contents of plants were of benefit to reduce the incidence of two diseases and obviously increased the control effects of the antibiotic. Cultural temperature, pH value of the medium, the usage of other fungicides and herbicides, especially the temperature and pH value showed influence on the inhibition rates of Jinggangmycin to R. cerealis and R. solani. At 22 C, the inhibitory effect of the antibiotic with 0.2 g/ml Jinggangmycin to R. cerealis was the highest, which was significantly different from that at 15C or 28 C. The second was at 28 C, but the inhibition rate at 28 C was not obviously different from that at 15 C. Furthermore, the inhibition of the antibiotic with 0.2 u g/ml Jinggangmycin to R. solani at 28 C was the highest, which was significantly different from at 21 C or 35 C, but there were not significant difference in the inhibition between at 21 C and at 35 "C. When pH value of the medium was 5 to 7, the inhibition of the antibiotic was higher than that on the medium of pH9. Thus, the stability of cultural temperature, pH value of media was of importance to detect the sensitivity of R. cerealis and R. solani to Jinggangmycin. The fungicides and herbicides tested, such as carbendazim, triadimefon, tebuconazole, fenoxaprop-p-ethyl, fluroxypyr, tribenuron methyl, acetochor, butachlor, had some inhibitor on the pathogen and could inhibit the mycelial growth. Furthermore, these fungicides and herbicides increased the inhibitory effects of Jinggangmycin against R. cerealis and R. solani. With increase in the concentration of these chemicals, the sensitivity of the pathogens to Jinggangmycin was increased, and the sensitivity of R. solani to the antibiotic was more obviously increased than that of R. cerealis.更多还原