Species,Damage and Emergence Characteristics of Weeds in Tobacco Fields in Deyang,Sichuan Province

Weed species and their damage of weeds in tobacco fields in Deyang were investigated in 2013 and 2014 by using inverted W9-point sampling method and the seven visual method. Emergence characteristics of weeds were surveyed at fixed-points in the field in 2014. There were 67 weed species belonging to 24 families. The dominant weed populations were composed by Echinochloa colona( L.) Link,Digitaria sanguinalis( L.) Scop.,Stellaria media( L.) Cyr.,Cardamine hirsuta L. and Polygonum flaccidum Meissn. The peak weed emergence occurred between 20 and 30 days after tobacco seedling transplanting in 2014. This study characterized the weed populations associated with tobacco fields,and provides pertinent information to establish appropriate weed control measures.