亚洲玉米螟为害对玉米镰孢穗腐病发生程度的影响

为了明确亚洲玉米螟Ostrinia furnacalis(Guenée)]在玉米雌穗不同发育期为害对玉米镰孢穗腐病发生程度的影响,分别在春播和夏播玉米吐丝、灌浆和乳熟期,以亚洲玉米螟为试虫,以轮枝镰孢菌为供试菌,单独或复合接种侵染。结果表明,无论春播还是夏播玉米,镰孢穗腐病病情指数均以复合处理最高,为31.57～88.80,单独接虫处理为16.27～55.00,单独接菌处理为19.02～59.47;玉米镰孢穗腐病的发生程度受玉米雌穗发育期和亚洲玉米螟为害程度的影响,其玉米螟为害级别为吐丝期>灌浆期>乳熟期;受螟害的介导作用,春播玉米雌穗被害率、螟害级别和镰孢穗腐病的发病率均显著重于夏播玉米,但夏播玉米镰孢穗腐病的病情指数高于春播玉米。螟害的介入明显加重了玉米镰孢穗腐病的发生,严重程度与雌穗发育时期密切相关。

Effects of the Asian corn borer injury on the incidence of Fusariumear rot caused by Fusarium verticillioides at different developmental stages of corn ear

The relationships between the injury by the Asian corn borer, Ostrinia furnacalis (Guenée), and the incidence of Fusarium ear rot at different developmental stages of corn ear were investigated. The corn ear was inoculated with O. furnacalis neonate larvae and Fusarium verticillioides, separately, or together at different developmental stages of corn ear on spring and summer corn, respectively. The results showed that the disease index was higher in the treatment inoculated with O. furnacalis together with F. verticillioides than that inoculated with O. furnacalis and F. verticillioides, separately, both in spring and summer corn. The disease index in complex treatment was from 31.57 to 88.80, but the treatment inoculated with neonate larvae of Asian corn borer or F. verticillioides only was from 16.27 to 55.00 and 19.02 to 59.47, individually. Incidence of Fusarium ear rot caused by Asian corn borer only and Asian corn borer with F. verticillioides together was highest, followed by the incidence by F. verticillioides only, then the control. The incidence of Fusarium ear rot to the corn was different with the damage degree of corn borer. The incidence of ear rot on spring corn was significantly higher than that on summer corn due to the damage caused by the Asian corn borer, but the disease index on summer corn was higher than on spring corn. The incidence of Fusarium ear rot was significantly increased when inoculated with O. furnacalis. The incidence and severity of Fusarium ear rot was significantly correlated with the development stage of corn ear.