What are the main diseases of onions?

Onion appears on everyone's table as an ingredient. It is most famous for its smell and amazing lethality. However, onion itself is really fragile and easily eroded by some diseases. Let's follow the footsteps of pro-farming network to understand some common diseases of onion.

1. Downy mildew

A disease such as mildew is a disease that plants cannot avoid. Onions often suffer from downy mildew. Such diseases are mostly concentrated in the pedicel, that is, closer to the soil. White mold spots appear at the beginning of the disease, and gradually turn purple as the disease deepens, eventually causing the plant to collapse. In addition to the harm of the bacteria and humidity is too high, found after the use of 75% chlorothalonil wettable powder 600 times solution for control.

2. Purple spot disease

Purple spot disease occurs when more concentrated and leaf parts, and then slowly expand, time more concentrated in the rainy season, so we must do a good job of drainage. At the beginning of the disease, there will be some pale purple spots on the top of the leaves. As it spreads, it will show purple as the core and brown around it. Finally, the whole plant will wither and die. Control can choose 2% multi-antibiotic 30ppm pesticide spraying, leaf tips to focus on spraying, once a week, about an hour before night, lasting for a month.

3. Yellow dwarf disease

This is a disease caused by bacteria, the incidence of obvious phenomena, more concentrated in the early stages of growth. The disease spreads from leaves to whole, first leaves begin to turn yellow, new leaves become fewer and smaller, and finally the whole plant stops developing and slowly withers. After the disease is stable, the serious disease can be removed directly to avoid infection, and the lighter disease can be controlled with 1.5% Zhibingling emulsion 1000 times solution once a week for two weeks.

4. Onion deformity

Onions are generally caused by excessive nitrogen fertilizer leading to nutritional imbalance and maggots. Of course, environmental and other factors will also exist, but these two are more common. Symptoms are irregular growth of onions, roots can be observed on the outside of the grass, if the roots are thicker than other languages, and may be abnormal growth. Daily fertilization must be released in proportion, not single release, for maggots, then you can irrigate 50% dimethoate 1000 times solution into the soil, must cooperate with water irrigation effect is good.

The above are some common diseases of onions. For other diseases, this is a relatively common disease. Once the above situation is found, we must pay attention to it. We should pay more attention to the daily management of the field to avoid greater losses.