Investigation of Weed Species in Dry Land and Chemical Control Countermeasures in Pan County of Guizhou Province

Through summarizing investigation，prediction，prevention and control experience of crop disease，insect，grass and rat of Pan county，it was found that weed hazard degree for crop was not less than diseases and insect pests.Weed in dry land was especially serious harm.Grain yield loss was 10%~30%，which was caused by harm of weed in dry land.It caused great loss to agricultural production in Pan county.In order to achieve better weed control effect，inhibitory effect of herbicides on weed in dry land was tested.High efficacy，low toxicity and low residue herbicide to control dry land weed for Pan county was selected.Results showed that，effect of 50% dry grass net was the best，followed by 41% glyphosate.