What are the symptoms of late blight of potato and how to control it ?

Purple black patches occur on the top leaves and branches of the stem when the illness first appears. White fungus can be observed growing under such dots. Under more severe disease, the crop seems to be burned. This sickness has an impact on tuber settings as well. Spray azoxystrobin 23 SC @ 10 ml or mancozeb 75 WP @ 20 g or metiram 70 WG @ 20 g or metalaxyl M 4 percent + mancozeb 64 percent WP @ 20 g per 10 lit of water at the start of the treatment.