What are the latest major diseases of onions?

Onions mostly appear on everyone's dining table as a seasoning. They are best known for their smell, which has astonishing striking power, but in fact the onion itself is indeed very fragile and highly susceptible to attack by various diseases. Below, everyone, follow in the footsteps of Qinnong Web to learn about some common onion diseases.

1. Downy mildew

Mold-related diseases are an unavoidable type of disease for plants, and the one that commonly occurs on onions is downy mildew. This kind of disease mostly concentrates on the flower stalk, that is, the area relatively close to the soil. In the early stage of the disease, white mold spots appear first, and as the disease deepens they slowly turn purple, finally causing the plant to collapse. Besides the harm of the pathogen, this is also related to excessively high humidity. After discovery, 75% chlorothalonil wettable powder 600x solution can be used for control.

2. Purple blotch

When purple blotch occurs, it mostly concentrates on the leaf area and then slowly spreads. It mostly occurs during the rainy season, so everyone must do a good job of drainage. In the early stage of the disease, some light purple spots appear at the top of the leaves. As they spread, they present purple as the core with brown drying and withering around them, and finally the whole plant withers and dies. For control, 2% polyoxin 30ppm agent can be selected for spraying, with the leaf tip area needing extra emphasis in spraying, once a week, about one hour before nightfall, lasting for one month.

3. Yellow dwarf disease

This is a disease caused by pathogens. The symptoms are obvious and mostly concentrate in the early growth stage. The disease spreads from the leaves to the whole plant. First the leaves begin to turn yellow, new leaves become fewer and smaller, and finally the whole plant stops developing and slowly withers. After the disease occurs, depending on how stable the situation is, severely affected plants can be directly removed and taken away to avoid contagion, while mildly affected plants can be controlled with 1.5% plant disease spirit emulsion 1000x solution, once a week, for two weeks.

4. Onion malformation

Onions are generally caused by two things: nutrient imbalance caused by excessive nitrogen fertilizer and onion maggots. Of course, the environment and other factors can also be involved, but these two are relatively common. The symptom is irregular growth of the onion. From the outside, the root stem can be observed. If the root stem is thicker and larger compared with others, it is very likely malformed growth. In daily fertilization, it must be released in proportion, not as a single type. For onion maggots, 50% dimethoate 1000x solution can be poured into the soil, and it must be poured together with water for a good effect.

The above are some common onion diseases. Compared with other diseases, these occur relatively more often. Once the above situations are discovered, attention must be paid, and everyone should also pay more attention to daily field management to avoid greater losses.