What are the main common diseases in onion cultivation?

Onions mostly appear on everyone's dining table as a condiment, and they are most famous for their smell, which has astonishing impact, but in fact the onion itself is indeed very fragile and easily attacked by some diseases. Below, everyone can follow in the footsteps of Qinnong Network to learn about some common onion diseases.

1. Downy mildew

Diseases such as mold are unavoidable for plants, and the one that commonly occurs on onions is downy mildew. Such symptoms are mostly concentrated on the flower stalk, that is, the part relatively close to the soil. In the early stage of the disease, white mold spots first appear, and as the disease deepens they slowly turn purple, finally causing the plant to collapse. In addition to the harm of the pathogen, this is also related to excessive humidity. After discovery, 75% chlorothalonil wettable powder 600x liquid can be used for control.

2. Purple blotch

When purple blotch occurs, it is mostly concentrated 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 tips of the leaves. As they spread, they show a purple center with brown drying around it, and finally the whole plant withers and dies. For control, 2% polyoxin 30ppm agent can be selected for spraying. The leaf tip area should be sprayed emphatically, once a week, about one hour before nightfall, for one month.

3. Yellow dwarf disease

This is a disease caused by a pathogen, with obvious symptoms, mostly concentrated in the early growth stage. The disease spreads from the leaves to the whole plant. First the leaves begin to turn yellow, and the new leaves become fewer and smaller, and finally the whole plant stops developing and slowly withers. After the disease occurs, it should be stabilized according to the situation. Severely diseased plants can be directly removed and taken away to avoid infection. For mildly diseased plants, 1.5% zhibingling emulsion 1000x liquid can be used for control, once a week, for two weeks.

4. Onion deformity

Onions are generally caused by two things: nutrient imbalance due to excessive nitrogen fertilizer and onion maggots. Of course, environmental and other factors can also contribute, but these two are the more common ones. The symptoms are irregular growth of the onion. The root stem can be observed from the outside. If the root stem is thicker than the others, it is very likely to be deformed growth. In daily fertilization, it must be applied in proportion, not in a single way. For onion maggots, 50% dimethoate 1000x liquid can be poured into the soil. It must be applied together with water for a good effect.

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