Investigation on Occurrence and Distribution Status of Weeds in Tobacco Fields of Guizhou Province

In tobacco growth period,the occurrence and damage situations of weeds in tobacco fields of Guizhou province were surveyed by using inverted-w nine-spot sampling method.The results showed that 167 weed species in 121 genera belonging to 39 families were recorded.According to the evaluation of the importance of every weed species,there were 15 main weed species,including Digitaria sanguinalis(L.) Scop.,Setaria viridis(L.) Beauv.,Poa annua L.,Cynodon dactylon(L.) Pers.,Eleusine indica(L.),etc.There were 3 dominant weed species in Guizhou province,including Digitaria sanguinalis(L.) Scop.,Cyperus rotundus L.,Eleusine indica(L.).