At the onset of symptoms, reddish-brown spots appear on the leaves, gradually expanding into round lesions or irregular polygonal lesions, dark brown, 1 to 5 mm in diameter, and the central tissue of the late lesions turning grayish. When the disease is severe, the lesions are connected to each other, causing the leaves to yellow and fall early. In wet conditions, many brown moldy spots are formed below the leaf spot.
Control measures to remove diseased leaves in a timely manner, pay attention to ventilation and light transmission, reduce leaf surface humidity, reduce sunburn and mechanical damage. Immediately after flowering, spray 65% ​​Zedexite WP 500 to 600 times, or 50% Carbendazim WP 500 to 800 times, or 70% thiophanate-methyl WP 1000 times, every 10 hours Spray 1 time in ~14 days and spray 2~3 times.
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