Early defoliation of apple trees is a general term for apple brown spot, gray spot disease, spotted deciduous disease, rotten spot disease, and round spot disease. Among the most common and most harmful ones are apple spotted leaf disease and apple brown spot. Moisture Proof Lamps,Golden Moisture Proof Lamp,Environmental Moisture Proof Lamps,Environmental Protection Moisture Proof Lamp Hangzhou Lingjun Technology Co.,Ltd , https://www.lingjunelectrical.com
The overwintering site of apple spotted leaf disease is in victim leaves, shoots or bud scales. Spores are produced in the spring, and with the spread of wind and rain, there are two peak periods in one year. The first time was in late April to mid-June, and the second time in September. It mainly damages young leaves, especially the young leaves in the 20th day of exhibition. In the early stage of disease, brown spots appeared on the leaves, and there were purple halos around. When the conditions were appropriate, several lesions were connected, and finally the leaves scorch off.
Apple brown spot mainly winters in the fallen leaves. Spores produced in the spring are splashed with rain on leaves that are closer to the ground and become the primary source of infestation. After incubation for a period of time, they re-infect with wind and rain. Onset occurs from May to June, and the onset of disease occurs from July to August. . The main infestation of the old leaves, lesions on the leaves at the beginning of a brown dot, after the development of the ring pattern, needle-type (the most common), mixed three lesions. Causes old leaves to yellow and fall off, but the edges of the lesion remain green to form halos.