Analysis Of The Affecting Factors Of Corn Sheath Rot Disease Occurence

In recent years, the corn sheath rot disease has been wide spreaded in corn-plantingregions of China with a increasing influence by years. The affecting factors of this diseaseoccurence was not reported at home and abroad. In this study, the popularized maizevarieties in Northern China were selected as experimental materials. In year2012and2013,the pathogenic fungus, Fusarium proliferatum, was inoculated on the plants of differentmaize varieties planted in the field, the varieties with different resistance ability to thedisease were selected. Followed by measuring the disease severity of differentdevelopmental periods of maize and defensive enzyme activity to determine the sensitiveperiod of maize. We inoculated aphids and F. proliferatum on maize planted in thegreenhouse to find out the role of aphids played in occurence of the corn sheath rot. Themain results were summarized as follows:1. The results of inoculation on maize in field in2012and2013showed that theseventy maize varieties were made of three immunity varieties, sixty five high resistancevarieties and two resistance varieties. Middle resistance varieties and high sensitivevarieties had not been found. It means the most of maize varieties planted in NorthernChina show resistance of corn sheath rot.2. Different resistant varieties with different lignin content, lignin content of highresistant varieties were higher than that of resistant varieties.3. After inoculating F. proliferatum on maize at different growth stages, we foundout that the morbidity and disease index of early flowering stage were higher than theinitial bell stage, tasseling stage, filling and milk stage, and the defensive activity of earlyflowering stage was higher than the other stages. It was indicated that the early floweringstage was a high sensitive period of corn sheath rot.4. Corn aphid does not carry or spread F. proliferatum, but the mechanical woundsmade by its feeding behavior and honey-dew made by its excreting behavior can make thecondition of corn sheath rot worse.