Field Control Efficacy of Several Reagents against Northern Leaf Blight of Maize(Exserohilum turcicum)

[Objective] The paper was to screen suitable agents for controlling northern leaf blight of maize in field. [Method] Field efficacy test was conducted using the agents of propiconazole, azoxystrobin, propiconazole·azoxystrobin, coumoxystrobin·tebuconazole, coumoxystrobin·tebuconazole and azoxystrobin. [Result] At 14 d post secondary spraying, the control effects of 25% propionazole EC 168.8 g/hm^2, 25% azoxystrobin SC 300 g/hm^2, 18.7% propiconazole·azoxystrobin SC 196.4 g/hm^2, 40% coumoxystrobin·tebuconazole SC 180 m L/hm^2, 40% coumoxystrobin·tebuconazole SC 180 m L/hm^2＋ 25% azoxystrobin SC 300 g/hm^2 against northern leaf blight of maize were 77.35%, 77.11%, 78.13%, 74.60% and 80.94%, re-spectively. The agents were safe and harmless to maize. [Conclusion] Considering the production factors, 18.7% propiconazole·azoxystrobin SC196.4 g/hm^2 or 40% coumoxystrobin·tebuconazole SC 180 m L/hm^2＋ 25% azoxystrobin SC 300 g/hm^2 can be sprayed in production before the incidence or in the initial incidence of northern leaf blight of maize.

Control Effect of Sex Pherom one Lure against the Asian Corn Borer( Ostrinia furnacalis) in Field

We studied the trapping effects on Ostrinia furnacalis from the aspects of different hanging heights and different color traps. The results suggested that the hanging height of 1.5 - 2.0 m received a better trapping effect, but trap color had little impact on trapping effect. The sex pheromone traps at different densities were placed in corn field. The results showed that sex pheromone lure could trap adult O. furnacalis, and it was feasible to apply sex pheromone in short term fore- cast. Meanwhile, it reduced the number of larvae and eggs, thereby reducing the damage of O. furnacalis. The lure number of 10 per hm2 was more appropriate, which could result in increasing yield of 8.61% compared with control