A few days after spraying pear rust can kill the virus.

25 days. According to the relevant public information, when the leaves are damaged, orange-yellow circular lesions with many yellow spots are formed on the front of the leaves. When wet, pale yellow mucus overflows, and the small spots turn black in the later stage, and the tissues on the back of the leaves corresponding to the diseased spots thicken and grow grayish yellow hairs. Fruits, fruit stems, new shoots and petioles were damaged, and the lesions were similar to those on leaves in the early stage, and hairs were produced on the surface of the same lesions in the later stage.