In the early stage of the disease, there will be many small gray brown or gray white spots on the back of the leaves, gradually forming a reddish brown bulge. Gradually visible cleaning visible sparse black particles. When the disease is serious, the spots aggregate to form large spots, and the whole leaf withers.
Remove the diseased leaves in time after the disease is found. Keep basin soil dry and strengthen maintenance. Apply thin fertilizer once a month to avoid excessive nitrogen fertilizer.
After the onset of the disease, the drug control can be carried out in time, and 25% Shibaoke emulsion 1000 times liquid or 40% chlorothalonil suspension 500 times liquid can be sprayed.
At the onset of the disease, the leaves appeared nearly round or irregular spots, about 0.6-1.2cm in size, slightly sunken, and the edge of the spots appeared brown or dark brown. There are many small black spots around the spot. From June to July, the disease was the most serious.
During the maintenance, the watering should be moderate, and the basin soil should not accumulate water. In June to July, the relative humidity of plant growth environment should be reduced appropriately. Proper cooling does not create a suitable habitat for the bacteria.
In the early stage of spraying, 80% times of mannan zinc 800 times liquid + 3000 times wet spray control.
