2. Strictly clear the garden: carefully clean the fallen leaves in autumn and winter, cut off diseased branches, and burn and bury them centrally. Spraying 40% thiram arsenic wettable powder 100 times before germination to eradicate the source of the disease.
3. Forecast: It can be monitored by spore catcher. The method is to coat vaseline on the glass slide, hang ropes on the branches at a distance of 1.3 ~ 1.5 meters from the ground, and hang five ropes in the four corners and the center of the plot, changing 1 time every three days, and then take them off and examine them under a microscope.
On the fourth day of spore peak day, the size of small particles in the lesion can be seen; On the seventh day after the peak, the first disease spot was found in the field, which should be treated with pesticides.
4. Chemical control: Emphasis should be placed on protecting early leaves, and prevention should be given priority to. The first application should be in mid-May, and the second application should be seven days later. Spray the medicine again in mid-June, July and August.
Extended data:
symptom
It mainly harms leaves, causes early autumn, also harms new shoots and fruits, and affects tree vigor and yield. Brown spots appear in the leaves at the initial stage of infection, and then gradually expand to reddish brown with purple-brown edges. Dark spots or concentric rings often appear in the center of the infected site.
When the weather is wet, dark green to black mold can grow on both sides of the affected area, that is, conidiophore and conidia of the pathogen. High temperature and high humidity in summer and autumn lead to a large number of bacteria breeding, shortened disease cycle and rapid increase of leaf spot in autumn.
It affects the normal growth of leaves, often makes the leaves twisted and shriveled, and the diseased parts are scorched, easily blown off by the wind and incomplete. When the fruit is infected, the surface of young fruit will produce small black spots or rust spots.
References:
Baidu Encyclopedia-Apple Spotted Fallen Leaves