Growth and Decline and Control Countermeasures of Grape Downy Mildew

【Objective】In this paper,Grape downy mildew epidemic dynamics were investigated in Xinjiang in order to provide reasonable treatment time and type of chemicals against the disease.【Method】By 5-point method,epidemic dynamic of grape downy mildew was investigated in Changji city in northern Xinjiang;using the leaf disc method,it was determined for the sensitivity of different fungicides to the pathogen of grape downy mildew;the fungicides which were sensitive to grape downy mildew were screened by bioassay.【Result】In June and July,the amount of precipitation is one major factor which led to the popular of grape downy mildew in northern Xinjiang.The fungicides(SYBK and DuPont) showed strong virulence to grape downy mildew pathogen,more sensitive to downy mildew of grape than other fungicides,such as Oxadixyl+Mancozeb,and metalaxyl on grape downy mildew pathogen were very insensitive.The results of field experiment with 10 fungicides for 2 years showed that the control effect of the fungicides Anke,SYBX and Oxadixyl+Mancozeb to grape downy mildew were 61.59%-71.70% by spraying once every 7 days,continuous spraying 2 times,the relative control effect was better than that of other agents .【Conclusion】The occurrence extent of damage from downy mildew of grape in Changji city in Xinjiang had some relations with the sustained time and amount of precipitation. Three fungicides have a good anti-disease effect and inhibit the spread of the disease,and the low toxicity of pesticides on grapes safety,environmental pollution,should be widely applied.