Most of them occurred from late May to mid-July, and the lesions were yellow. At first, it started from the tip of the leaf, gradually expanded and spread, and in severe cases, the whole leaf withered and died. It is serious when it is hot and humid and has poor ventilation.

Prevention and control methods: Guo Liang 'an 100- 150 times+garlic oil 1000 times+waffen 600 times+silica gel spray for more than three times, with an interval of 5-7 days each time. * * Spray once a week and twice continuously before the onset of the disease.

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