How to prevent and cure the latest green onion white blight?

The white blight of scallions is a fungal disease. The pathogen overwinters mainly with chlamydospores in the soil. The sporangia are produced when the conditions are suitable in the next spring and spread by irrigation water or wind and rain. The newly produced spores on the disease spot and the zoospores on the surface are spread by raindrop splash. The disease can occur in both the seedling stage and the adult stage, and the damage site is the leaves of scallions. Let's take a look at how to control the white blight of scallions.

Symptoms of white blight of green onion

Spring onion white blight can occur in both seedling stage and adult plant stage. at seedling stage, leaf sheath and leaf body infected by adult plants appeared inconspicuous oil-soaked dark green disease spots around them, and then gradually expanded to a large oil-immersed bluish-white disease spot of 5 cm. The disease spot was white to gray in the center, and the disease spot spread to the leaf tip and gradually withered and drooped. As far as 1 plant was concerned, it was mostly at the same height in the initial stage, different from blight and botrytis.

Disease conditions of white blight of scallions

The pathogen overwintered mainly as chlamydospores in the soil, and sporangia were produced under suitable conditions in the next spring, which were spread by irrigation water or wind and rain, and new zoospores on the disease spot and surface zoospores were transmitted by raindrop sputtering. It usually starts from May to June, with the arrival of the rainy season, the disease is aggravated, the disease is easy to occur in continuous rainy weather in summer, the drainage is not timely after the rainstorm, and the disease is serious due to stagnant water, too much nitrogen fertilizer or overgrown plants.

How to prevent and cure the white blight of green onions?

1. Select disease-resistant and resistant varieties such as high-foot white, chicken leg spring onion, five-leaf Qi, Bikeqi green onion, Zhangqiu sycamore and so on.

2. Onion and garlic vegetables should not be planted in the affected area within 2 to 3 years. After harvest, attention should be paid to the removal of diseased and residual bodies, concentrated burial or burning.

3. Adopt high border or ridge cultivation and cultivate soil in time to avoid onion seedlings from coming into contact with water as far as possible.

4. The compost retted by enzyme bacteria can increase the disease resistance of the plant by applying less available nitrogen.

5. At the initial stage of the disease, 30% Ludebao suspension 400 times 500 times or 77% chlorpromazine wettable particulate powder 500 times, 60% ethyl phosphate aluminum wettable powder 500 times, 72% Kelou wettable powder or 72% frost urea manganese zinc wettable powder, 72% frost cyanide wettable powder 800 times, once or twice every 10 days. When there is resistance to the above fungicides, 69% Anke manganese zinc wettable powder or 1000 times water dispersible granule can be used.