贵州甘蔗真菌病害初步调查及褐斑病防治药剂筛选

为掌握贵州甘蔗真菌病害种类及发生情况,采用随机踏查、定点调查、症状诊断与病原菌形态特征观察等方法对贵州甘蔗产区7个县进行真菌病害调查;采用菌丝生长速率法,对甘蔗褐斑病进行了5种杀菌剂室内毒力测定和田间防效试验。结果表明,贵州甘蔗主要真菌病害有褐斑病、褐锈病、赤腐病、黄斑病、轮斑病、褐条病、煤烟病、黑穗病,其中褐斑病、轮斑病、褐条病发生较重,煤烟病发生严重;5种杀菌剂中,325g/L苯甲·嘧菌酯悬浮剂对甘蔗褐斑病毒力最高,防效最好,EC50为0.002 5mg/L,第3次药后10d防效达86.46%。其他4种杀菌剂对褐斑病均有较好的防治效果,可应用于甘蔗生产防治褐斑病。

Preliminary investigation of the fungal disease of sugarcane in Guizhou and screening of fungicides against Cercospora longipes

Egg-laying process of cotton aphid Aphis gossypii on its overwintering host Hibiscus syriacus Linn., and diffusion and immigration dynamics in the following spring were investigated regularly in a fixed spots in Yangzhou. Egg color, morphological characters of fundatrices and virginoparae, and egg shell were photoed using stereoscope. Results showed that most of the newly laid eggs were black, a minority of eggs were jade color and converted to black after 2 days. The end of December to the early January was the egg-laying peak season; The overwintering eggs hatched into fundatrices, and virginoparae occurred in the early April. In the mid-April, alatae appeared and started to diffuse. It was found that not all cotton aphids turned into alatae to emigrate from the winter host. This study will provide a scientific basis for the forecast and management of the cotton aphid in the early spring.