Autumn sowing vegetables pest control should be symptomatic

The sowing time of autumn vegetables is in the flood season. The characteristics of high temperature and rainy climate determine the occurrence of pests and diseases. It is necessary to grasp the characteristics of pests and diseases in a timely manner.

Pests and diseases have characteristics

The main diseases are downy mildew, soft rot, and viral diseases.

Downy mildew

Generally, the disease is mainly caused by adult stage, the symptoms are the most obvious, mainly affecting the leaves. At the early stage of the disease, water-immersed light green spots appear on the leaves, which are polygonal by the veins. When the humidity is high, the back of the lesions grows mildew. In severe cases, the lesions can be connected to cause the leaves to die dry. Downy mildew bacteria prefer warm and high humidity conditions, so the temperature difference is large even in cloudy days or day and night, the condensation time is long or the drainage is not smooth, and the ventilation is bad.

Soft rot

Mostly bacterial, the common feature is that the diseased part is sticky and soft and rot, accompanied by bad odor. In recent years, the soft rot of Chinese cabbage has been seriously affected, generally reducing production by 10-20% and serious land by more than 50%. Soft rot occurs mainly through wound invasion, such as insect damage, mechanical damage, natural cracks, etc., so avoiding wounds can reduce the occurrence of soft rot.

Viral disease

The main symptoms are mosaic, shrinkage, deformity, etc., which are mainly transmitted by acarids such as aphids, whitefly, and gray planthoppers. The conditions of high temperature and dryness are conducive to the reproduction of aphids, and the occurrence of viral diseases is serious. Once a viral disease occurs, prevention and treatment is difficult, and cutting off the drug delivery medium is a key measure to prevent viral diseases.

The main pests are cotton bollworm, beet armyworm, Spodoptera litura, cabbage caterpillar, diamondback moth, aphid, whitefly, spotted fly, bandit, cockroach, leafhopper, snail, wild donkey, yellow stripe, and tiger. , Golden worm, cockroach, cockroach, etc. The seedling stage of Chinese cabbage is a concentrated period of various pests, which often causes the lack of seedlings to break the ridges and destroy the seeds. It is the key to control the seedling stage.