Protective fungicides can be used for spray protection before the outbreak of late blight. If the disease is obvious before application, drugs with therapeutic, eradication and protective effects should be used for the first time to reduce the bacterial source base.
Extended data:
It is worth noting that Phytophthora infestans is a pathogen with high resistance risk because of its easy resistance. The resistance of potato late blight to metalaxyl is widespread all over the world, and so is the resistance of potato late blight to metalaxyl in China, which has the characteristics of wide occurrence area, high resistance level and rapid development.
However, there is no resistance to other types of fungicides such as acetamide, carboxamide and methoxyacrylate. At present, there is no report on the resistance of Phytophthora infestans to dimethomorph. Potato late blight has not yet produced resistance to cymoxanil.
Therefore, in the process of medication, it is necessary to limit the use times of a single fungicide, take turns to take medication, and jointly use fungicides with different mechanisms of action, especially generic drugs and fungicides with similar duration. Use according to the recommended dosage, give priority to protective application, avoid therapeutic and eradication application, strictly control the use times in each growing season, and reduce the risk of drug resistance of pathogenic bacteria.
Xinhuanet-Potato Late Blight