三株病原真菌对稗草生防潜力的研究

从稻田中采集自然感病的稗草标样,分离获得10余种病原真菌,经生测,链格孢菌、尖角突脐孢菌和内脐孢菌是3株很有希望的稗草生防潜力菌。对它们的生长及产孢特性、寄主范围及孢子悬浮液喷雾接种对水稻和稗草的致病性等进行了研究。结果表明,3个菌各有优缺点。链格孢菌对稗草致病力稍差,对水稻有轻度感染,但其产孢速度快,产孢量大;尖角突脐孢菌对稗致病力强,对稻无影响,但产生孢子慢,产生菌丝多;内脐孢菌对稗致病力强,对稻安全,菌落生长较慢,但产孢速度快,产孢量多,气生菌丝少。黑暗、空气充足有利于3菌株的生长及产孢。

THE BIOLOGICAL CONTROL POTENCIALITY OF THREE PATHOGENIC FUNGI TO BARNYARDGRASS(ECHINOCHLOA SPP.)

More than 10 pathogenic fungi were isolated from the natural infected samples of barn-yardgrass ( Echinochloa spp.) in paddy fields. By preliminary bioassay, Altemaria alternata ( AA) , Exserohilum monoceras (EM) and Drechslera monoceras (DM) showed the potential for biological control to bamyardgrass. The growth, conidium production, host range and the pathogenicity of spore suspension of the three fungi to rice ( Oryzae saliva ) and barnyardgrass seedlings were studied. The results showed that AA, EM and DM had respective advantages and defects as mycoherbi-cides. The AA fungus showed characteristics of fast growing and producing large number of conidia. The pathogenicity of AA to barnyardgrass was lower than the other two fungi, and it slight infected rice. EM was highly pathogenic to barnyardgrass and safe to rice, however its colonies grew slowly with fewer conidia. DM has strong pathogenicity to barnyardgrass and safety to rice, and the production of its spores was great and it has less aerial mycelia although the colonies of DM grew slowly. Darkness and abundant air was favourable to growing and conidium production of the three fungi.