新化合物氟醚菌酰胺的抑菌活性及其对棉花立枯丝核菌的作用方式研究

Study on fungicidal activity and mode of action of a novel fungicidal agent,LH-2010A against Rhoizoctonia solani

采用菌丝生长速率法测定了新化合物氟醚菌酰胺(LH-2010A)对10种常见植物病原菌的毒力,同时研究了其对棉花立枯丝核菌无性繁殖过程、菌丝形态及细胞膜通透性的影响。结果表明:氟醚菌酰胺对10种病原菌均具有较强的抑菌活性,比结构相似的选择性杀菌剂氟吡菌胺具有更广的杀菌谱。氟醚菌酰胺对棉花立枯丝核菌和番茄灰霉病菌的抑菌活性最高,EC50值均小于1.00μg/mL,对其他8种病原菌的EC50值则在1.10～4.63μg/mL之间;而氟吡菌胺只对辣椒疫霉和马铃薯晚疫病菌具有较高的抑菌活性,EC50值分别为0.61和0.72μg/mL。在100.0μg/mL下,氟醚菌酰胺对棉花立枯丝核菌抑菌作用明显,能显著抑制其菌核产生和菌丝生长量,使菌丝分支增多、变短、变粗;以不同浓度的氟醚菌酰胺处理棉花立枯丝核菌时,其细胞膜的通透性随着药剂浓度的增加而显著增大,520 min时最高处理浓度下的相对渗率为77.01%。表明氟醚菌酰胺对多种植物病原菌具有较高的抑菌活性,并能明显抑制棉花立枯丝核菌的多项生理指标。

The mycelial linear growth rate method was adopted to determine the toxicity of LH-2010A to 10 pathogens, and the effects of LH-2010A on the process of asexual reproduction, membrane permeability and mycelial morphology of Rhizoctonia solani were also detected. The results indicated that LH-2010A had broader fungicidal spectrum than another formamide fungicide, fluopicolide with effective activity against 10 pathogens. The highest toxicity of LH-2010A to R. solani and Botrytis cinerea were obtained with EC50value less than 1.00 μg/mL,while the eight others with EC50 1.10 -4. 63 μg/mL. However, fluopicolide only exhibited high toxicity to Phytophthora capsici and Phytophthora infestans with ECso values as 0.61 μg/mL and 0.72 μg/mL, respectively. In addition, LH-2010A had high fungicidal activity against sclerotinia and mycelial growth of R. solani, and it only showed inhibitory effect on R. solani at concentration less than 100.0 mg/L. Moreover,the amount of ramification increased and the mycelium formed irregular ramification or abnormal configuration （contracted or swelled up ） on mycelium tip. With the increase of LH-2010A concentration, the membrane permeability of R. solani increased, and the highest relative leakage reached 77.01% at 520 rain. In conclution, LH-2010A has high fungicidal activity against various pathogens and it can inhibit some physiological characteristics of R. solani.