玉米三种叶斑病混发时的流行过程及产量损失研究

 通过2年的田间小区人工接种试验，观察比较了玉米大斑病、弯孢叶斑病和灰斑病单独及混合发生时的流行过程及对玉米产量损失的影响。结果表明，在病害混发初期，病害间无明显的负相关性，随着病情的发展，病害间的负相关性逐渐增大并达到显著水平，说明病害间有明显的抑制作用。病害混发时造成产量损失并不完全等于各病害单独造成损失之和，其中大斑病和弯孢叶斑病、弯孢叶斑病和灰斑病混合发生所造成的损失约为各病害单独造成损失之和的76%～88%，大斑病和灰斑病混合发生所造成的损失可近似看作两种病害各自引起产量损失之和，3种病害同时发生时最终损失率约为各自造成损失之和的67%～72%。

Epidemic processes and yield loss of northern leaf blight (Exserohilum turcicum), Curvularia leaf spot (Curvularia lunata) and gray leaf spot (Cercospora zeae-maydis) of maize when they occurred together in the field

The epidemic processes and yield loss of northern leaf blight (Exserohilum turcicum), Curvularia leaf spot (Curvularia lunata) and gray leaf spot (Cercospora zeae-maydis) of maize were observed in the field plots for two years. The results showed that when three diseases occurred together, there was some inhibition among different diseases. The interaction was too weak to be checked with statistical methods when the disease was very low, and it got significant as the disease increased. The yield loss when three diseases occurred together, did not absolutely equal to the sum of that caused by every single disease. The yield loss caused by northern leaf blight and Curvularia leaf spot or Curvularia leaf spot and gray leaf spot were about 76%~88% of the sum of yield loss that caused by the corresponding single disease. The yield loss caused by northern leaf blight and gray leaf spot was equal to the sum of yield loss that caused by the corresponding single disease. The yield loss caused by three diseases were about 67%-72% of the sum of yield loss that caused by the corresponding single disease.