Species and Distribution of Weeds in Tobacco Fields in Yichang City

In order to clarify the weed species and distribution of main tobacco districts in Yichang, determine the major weed species harmful to tobacco production and provide technical support for improving the production and quality of tobac- co,10 sample sites in tobacco fields from Zigui county, Xingshan county and Wufeng county in Yichang were selected to survey weed. The results showed there were 53 weed species belonging to 22 families in tobacco fields in Yichang. According to weed density, the dominant species were Digitaria sanguinalis, Polygonum nepalense and Galinsoga parvifl. According to weed growing frequency, weeds with high frequency were ranked as Polygonum nepalense, Acalypha australis, Digitaria san- guinalis, and Galinsoga parvifl. Moreover, altitude had certain influence on the species and distribution of weed, weed species being more abundant at lower altitude.