Garlic has a viral disease.

Dai Hongming, Baimi Town, Jiangyan City, called on December 1 to say that his 2 mu of garlic was in the 5-6 leaf stage. Recently, 50% of the plants in the field had yellow and distorted leaves, their roots were white, and herbicides had not been used in the early stage. He asked what was wrong with garlic and how to prevent it.

On December 3, Agricultural Technology 001 Studio received the sick garlic seedlings he sent by express mail. After careful examination, the diseased seedlings were roughly at the stage of 3-5 leaves, with intermittent short yellow-green stripes on the 1-2 leaves at the base, some leaf tips had dried up, the upper leaves had long yellow-green spots, and some plants had yellowed heart leaves; each leaf was twisted and deformed, and the upper part of the heart leaf was wrapped by adjacent leaves and could not protrude normally. The pseudostem of the diseased plant is thin, the growth is thin, and the root growth is basically normal. Zhou Yijun, a researcher from the Plant virus Disease Group of the Plant Protection Institute of Jiangsu Academy of Agricultural Sciences, diagnosed that the garlic had a virus disease after carefully looking at the diseased garlic plants.

It is understood that garlic virus disease is caused by a variety of viruses. At the initial stage of the disease, intermittent yellow stripes appear along the leaf veins, then connect into yellow and green stripes, the plants are dwarfed, and the heart leaves of individual plants are surrounded by adjacent leaves, showing curly deformities, and can not be fully extended for a long time, causing the leaves to twist. The bulbs of diseased plants became smaller, garlic cloves and fibrous roots decreased, and severe garlic cloves were stiff, especially during storage. Once the virus invades the plant, it not only has an impact on the present age, but also the mother of the bulb can be transmitted vertically to the offspring, resulting in species degradation.

The high temperature and drought environment is beneficial to the occurrence of garlic virus disease, and the optimum temperature is 20-30 ℃, and the relative humidity is about 70%. The main peak period of garlic virus disease in the middle and lower reaches of the Yangtze River is from September to November in autumn and from April to June in spring. Garlic is susceptible to disease from seedling stage to adult stage. When the poisonous bulbs are sown, the plants become sick immediately after emergence, and the virus is not transmitted persistently by aphids in the field. There are a large number of aphids, high temperature and drought, extensive management and serious disease in continuous cropping with other Allium plants.

According to the telephone return visit, the garlic in the above-mentioned fields was harmed by more aphids at the 2th and third leaf stage, and the aphids were not controlled in time when the aphids occurred, which led to the occurrence of a large number of aphids. In the early stage of garlic growth this year, the temperature is on the high side and there is not much Rain Water, which is conducive to the occurrence of aphids. The occurrence of a large number of aphids is the main cause of virus disease in garlic in the above-mentioned fields. In addition, garlic plant growth is thin, disease resistance is poor, coupled with the lack of timely use of drugs to control aphids, resulting in the spread of virus disease and aggravation of the disease.

After the occurrence of virus disease in garlic, there is no effective drug to control the disease, mainly through the prevention and control of virus-borne aphids. To control aphids, acetamiprid, imidacloprid, imidacloprid, carbofuran, thiazine, thiacloprid, deltamethrin, aldicarb and other drugs can be selected. In addition, in order to prevent garlic virus disease, strict seed selection and virus-free garlic seeds should be selected; rotation for 3-4 years should be carried out to avoid continuous cropping with garlic and other onion crops; fertilizer and water management should be strengthened to avoid premature senescence and improve plant disease resistance.