Citrus scab and its specific drugs

Citrus scab is a common fungal disease in the process of citrus cultivation. In order to effectively prevent it, we must first understand it. What does citrus scab and specific medicine have?

1. Citrus scab

The main results are as follows: 1. The pathogen of the disease is Citrus eschar Cyclospora, which belongs to Citrus. The scab pathogen overwinters as mycelia in the diseased tissue. When the temperature rises to more than 15 ℃ in spring and when it is rainy and humid, the old disease spot produces conidia, which is transmitted by wind, rain or insects to the tender leaves, flowers and young fruits of spring shoots. After invading the epidermis, new disease spots appear during the incubation period of 3-10 days, and the initial infection is completed.

2. After that, conidia were produced to harm the tender leaves, shoots and fruits of summer and autumn shoots, and overwintered with mycelium in the diseased part. The most suitable temperature for the disease was 20-21 ℃, and the disease stopped when the temperature exceeded 24 ℃. If the new shoots and leaves are exposed to continuous rain, or heavy fog reappears in the early morning, the disease is easy to spread. Therefore, temperature and humidity play a decisive role in the occurrence and prevalence of scab.

3. The main characteristics of citrus scab: it mainly harms the young tissues of leaves, shoots and fruits, as well as calyx and petals. The leaves were damaged and greasy yellow-brown round spots were produced at the initial stage, which gradually expanded and the color became waxy yellow. In the later stage, the disease spot cork and bulge, multi-directional leaf back protruding, leaf surface depression, into a conical grayish brown scab. The diameter of lesion was 0.3-2mm. The leaves of early severely damaged shoots often withered and scorched off. When the weather is wet, grayish-brown powdery matter (conidia disk and conidia of bacteria) grow on the surface of the disease spot. Sometimes many disease spots come together, making the leaves twisted and deformed.

II. Specific drugs for citrus scab

The main results are as follows: 1. Focus on the prevention and treatment of young fruit scab, spray at 2 / 3 of the flower, and spray again half a month later when the disease conditions are particularly favorable. 0.8% equal Bordeaux solution can be selected for the first application, and 0.6 jin of salt is added to the Bordeaux solution, which has the effect of synergism and resistance to Rain Water scouring, and has a special effect on the treatment of citrus white plaster disease.

2. The effective medicament varieties are Bordeaux solution, 55% thiocarbamate wettable powder 1000-1200 fold solution, 50% carbendazim wettable powder 800-1000 fold liquid, 77% carbendazim 2000 wettable powder solution, 80% essential wettable powder 400,600 fold liquid, 80% Sanderson (Dasheng M-45) wettable powder 600x liquid, 30% copper dicarboxylic acid wettable powder 400500x solution, 20% Longke (germicidal copper) gum suspension 500x. 12% carbendazim EC 500 times.

Good control of temperature and humidity, at the same time do a good job of chemical protection, effectively control the occurrence of diseases.