Study on the Control of Potato Late Blight by Using Metalaxyl Granule

Wang Ren gui;Liu Lihua;Xia Ping(Potato Institute, Heilongjiang Academy of Agr Sei.)

Potato late blight, Metalaxyl granule

The efficacy of metalaxyl granule made of different materials on the control of potato late blight was Studied in two consecutive years. The field-plot experiment demonstrated that all three type of metulaxyl granule applied to the root produced better control on late blight disease than the metalaxyl spraying. Among the three type of metalaxyl granule, namely meralaxyl-charcoal, metalaxyl cinder powder and metalaxyl with mixture of charcoal and cinder powder, use of metalaxylwih mixture of charcoal and cinder powder led to the best control of the disease and highest yield increase even at late growing season, the disease controling efficiency was still above 70% which resuled in 679kg per mu increase of potato production compairing to the control plot without using any chemicals for disease control. No significant yield difference was found between the plots utilizing the granule made with either charcoal or cinder powder. The disease control efficiency of using cinder powder granule decreased with the reduction of active agent concentration contained in the granule. A comprehensive economic analysis of using cinder powder granule showed that applying 200g of metalaxyl mixed with 10kg cinder powder would be the practical one for future extension in Heiongjiang province.