丹参茎基腐病病原鉴定及防治药剂筛选

Identification of basal stem rot causal pathogen in Salvia miltiorrhiza and evaluation of fungicides on the inhibition of mycelial growth in laboratory

近年来,河南丹参产区发生一种新的病害,将其命名为茎基腐病害。为明确该病害的病原,课题组从河南丹参产区采集典型病害标本并进行病原菌分离,共获得25株真菌分离物,其中23个分离物(SM1-SM23)形态与链格孢属真菌一致,2个分离物(SM24-SM25)形态与镰刀菌属真菌一致。选取代表性菌株SM10和SM24对丹参茎基进行致病性测定,分离物SM10能够引起与病样一致的症状,并且在发病部位重新分离出该病原菌,完成科赫氏法则验证。通过形态及分子特征鉴定确定引起丹参芝基腐的病原菌为细极链格孢(Alternaria tenuissima)。在温度为28℃,光暗交替(12 h)最有利于病原菌的生长,pH值在5~11之间该菌生长良好,菌丝生长的最适碳氮源为可溶性淀粉和蛋白胨,产孢的最适碳氮源为乳糖和酵母浸出物。毒力测定结果表明,参试的5种药剂均对A.tenuissima有抑制效果,其中25%吡唑醚菌酯悬浮剂、43%戊唑醇悬浮剂和10%苯醚甲环唑水分散粒剂对病原菌菌丝生长具有较好的防治效果,质量浓度为50 mg·L^(-1)时抑菌率分别为78.4%、100%和93.3%,可作为防治丹参茎基腐病的主选药剂。

In recent years,a new important disease in Salvia miltiorrhiza was found in Henan Province,and named as the basal stem rot of S.miltiorrhiza.To determine the pathogen,the typical diseases samples were collected from producing areas in Henan Province for isolation.A total of 25 pure isolates were obtained in which 23 isolates(SM1-SM23)exhibited consistent and typical characteristics of Alternaria sp.,while 2 isolates(SM24-SM25)similar to Fusarium sp..The further pathogenicity test on the detached stems of S.miltiorrhiza with the representative isolates,SM10 and SM24,was conducted.The isolate SM10 could cause the similar disease symptoms and the re-isolation of pathogen fulfilled the Koch’s postulate.The SM10 was identified as Alternaria tenuissima,causing basal stem rot of S.miltiorrhiza,based on the morphological and molecular characteristics.The colony radial growth of SM10 was fastest at 28℃with 12 h light/dark photoperiod.The pathogenic isolate SM10 was able to grow well under pH 5-11.The most suitable carbon and nitrogen sources for mycelial growth were soluble starch and peptone,while lactose and yeast extract suitable for sporulation.The five fungicides tes-ted displayed inhibition of the SM10 radial growth in the laboratory.Three of them,25%pyraclostrobin suspending agent,43%tebuconazole suspending agent and 10%difenoconazole water dispersible granule,exhibited more stronger inhibition at the concentration was 50 mg·L^(-1)with the rates of 78.4%,100%and 93.3%,respectively,which could be used as the main fungicides to control the basal stem rot of S.miltiorrhiza.