禾生指葡孢霉生物学特性及室内药剂筛选

为了给青稞和燕麦鞘腐病的科学防治提供技术支持,对其病原菌-禾生指葡孢霉的生长温度、适宜培养基种类、适宜pH值、存活时间等生物学特性进行了研究,并选取麦类作物上常用的8种杀菌剂进行了室内药剂筛选。结果表明,禾生指葡孢霉在5~30℃下可生长,适宜生长温度为20~25℃;在PSA、PDA、CA、CMA和OMA培养基平板上均可生长、产孢,适宜病菌生长、产孢的培养基为PDA和PSA;在pH值为4~10的PDA平板上均可生长、产孢,适宜生长的pH值为6~10;在5~10℃冷藏条件下,禾生指葡孢霉存活时间超过5a。在试验浓度(推荐剂量)下,8种杀菌剂对禾生指葡孢霉菌丝生长均具有不同程度的抑制效果,其中50%多菌灵可湿性粉剂(500×)、70%代森锰锌可湿性粉剂(500×)、430g·L-1戊唑醇悬浮剂(5 000×,8 000×)和400g·L-1氟硅唑乳油(5 000×,10 000×)的抑菌效果达100%。

Biological Characteristics of Dactylobotrys graminicola and Fungicides Screening Test in Vitro

Sheath rot of hulless barley and oats,caused by Dactylobotrys graminicola,is a new disease in the highlands of Gansu province and the neighboring region in recent years.In order to providing technical support for the disease controlling,biological characteristics(cardinal temperatures,proper medium,optimum pH value,survival time,etc.) and fungicides screening of Dactylobotrys graminicola in vitro were investigated.The fungal cardinal growth temperatures were evaluated by temperature gradients method.The proper medium and pH value were evaluated by hyphae growth and condia production situation on different culture medium plates and on pH 4 to 10 PDA plates,respectively.The fungal survival time was assessed by determination of the survival situation of preserved strains on a regular basis(every six months) and fungicides amendment(medicated plate method) were assessed for inhibitory effect on Dactylobotrys graminicola in vitro with eight different fungicides.The results showed that Dactylobotrys graminicola can grow at 5 to 30 ℃,the optimal growth temperature is 20~25 ℃.The fungus can grow and sporulate on PSA,PDA,CA,CMA and OMA plates,of which PDA and PSA are more suitable for the fungal growth and sporulation.The fungus can grow and sporulate on PDA plate with pH value 4 to 10,and suitable pH value ranges from 6 to 10.Survival time of Dactylobotrys graminicola was longer than 5 a at 5 to 10 ℃.Under test concentrations(recommended dose),all eight fungicides could inhibit the mycelial growth of Dactylobotrys graminicola,of which carbendazim 50% WP(500×),mancozeb 70% WP(500×),tebuconazole 430 g?L-1 SC(5 000×,8 000×) and flusilazole 400 g?L-1 EC(5 000×,10 000×) made inhibitory effects up to 100%.