Disease Prevention and Control Methods for Azaleas in Spring and Summer
What diseases should azaleas be protected from in spring and summer? The diseases that azaleas are prone to in spring and summer include: (1) Black spot disease. If azaleas (including large-flowered azaleas and all types of Western azaleas) are placed in a stuffy, unventilated location and are kept in shade for a long time, then when humid weather occurs or when daily watering is excessive, this disease is easily triggered; it is...
What diseases should azaleas be protected from in spring and summer?
The diseases that azaleas are prone to in spring and summer include:
(1) Black spot disease. If azaleas (including large-flowered azaleas and all types of Western azaleas) are placed in a stuffy, unventilated location and are kept in shade for a long time, then when humid weather occurs or when daily watering is excessive, this disease is easily triggered; it is caused by a fungus and spreads through the air. If the air in the surrounding growing environment is polluted, spots are also easily caused on the leaves. The fungal spores fall into the potting soil and first grow hyphae on old and weak leaves, spreading quickly and causing the leaves to drop from the bottom upward.
(2) Brown spot disease. During the plum rain season, with high temperatures and high humidity, small brown spots easily appear on the leaves, causing the leaves to turn yellow, dry out, wrinkle, and then fall off. The usual prevention and control method is the same as for black spot disease: increase stronger diffused light and move the plant to a place with air circulation and drier conditions. For chemical treatment, use "Topsin" at 800 times dilution, or "Zhibao" at 1000 times dilution.
(3) Chlorosis. It is caused by iron deficiency and insufficient trace elements, or by the planting soil being too alkaline; you can bury a few rusty iron nails in the soil, or sprinkle a little ferrous sulfate into the pot, 1 gram each time.
(4) Stem rot. Because of damp and shady conditions, fungi invade the cortex, cutting off the transport channels for water and nutrients, and the leaves dry up. In daily care, appropriately increase potassium fertilizer, increase light, and move the plant to a place with air circulation.
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