盾壳霉控制油菜菌核病菌再侵染及其叶面存活动态的研究

 本文评估了施于油菜(Brassica napus)叶片上的盾壳霉(Coniothyrium minitans)控制油菜菌核病菌再侵染能力,探讨了其作用机理,并测定了盾壳霉分生孢子在油菜叶面上的存活动态。结果如下:叶面上的盾壳霉对油菜菌核病菌的初侵染影响较小,但在高剂量(> 10⁶孢子/ml)时可以控制病斑的扩展。所有供试剂量的盾壳霉均可不同程度地控制再侵染。盾壳霉分生孢子可在叶面病部迅速萌发,48 h和72 h时孢子萌发率分别为51%和95%,而在健康叶面上6 d未能检测到萌发的孢子。自携带盾壳霉的叶面病部不能分离到核盘菌,表明叶面上的盾壳霉已寄生并破坏了核盘菌再侵染菌丝。自油菜叶面上分离到的盾壳霉菌落数随时间延长而降低,但其分生孢子至少可以在叶面上存活28 d。这即表明,在叶面上适时适量地添加盾壳霉可以控制油菜菌核病的为害。

BIOCONTROL OF REINFECTION OF OILSEED RAPE STEM ROT CAUSED BY Sclerotinia sclerotiorum BY Coniothyrium minitansAND ITS SURVIVAL ON LEAF OF OILSEED RAPE (Brassica napus)

In this paper, the ability of Coniothyrium minitans to inhibit the infection of oilseed rape ( Brassica napus )stem rot caused by Sclerotinia sclerotiorum was assessed. The survival of the conidia of C.minitans on the leaf of oilseed rape was also examined. The results showed that C.minitans on the leaf could not prevent the primary infection of S.sclerotiorum although it could influence the expansion of lesion at high concentration (>10 6 conidia per ml). The reinfection of stem rot by diseased leaves could be decreased effectively when the leaves carried any dose of conidia of C.minitans tested. The germination of the conidia of C.minitans could be stimulated by S.sclerotiorum on lesion to the rate of 51 percent and 95 percent, respectively, after 48 hrs and 72 hrs, while on health leaf there was not any germination of conidia even after six days. S.sclerotiorum could not be isolated from diseased leaf that carried conidia of C.minitans at different doses tested. So it suggested that the hypha of S.sclerotiorum on lesion could be parasitized and destroyed by C.minitans . The amount of cfu of C.minitans isolated from health leaf dropped gradully as time goes on, while the conidia could survive on surface of leaf for at least 28 days. According to these results, C.minitans has great potential to control oilseed rape stem rot caused by S.sclerotiorum .