Which methods can control vegetable nematode disease?

In recent years, nematode disease in vegetable fields, especially in protected areas, has become increasingly serious. It occurs in almost all vegetables, such as cucumbers, balsam pears, tomatoes, carrots, eggplant, potatoes, sweet potatoes, kidney beans and even spinach. Due to the strong concealment of nematode disease and difficulties in prevention and control, farmers have suffered serious losses in production and income reduction. How should nematode disease be diagnosed? What are the good ways to prevent and cure it? For this reason, the reporter interviewed Professor Xiao Yueyan, School of Agronomy and Biotechnology, China Agricultural University.

Xiao Yueyan pointed out that nematode diseases have indeed gradually increased in vegetable fields, the main reasons are: first, one or two kinds of vegetables have been planted continuously for a long time, and the number of pathogenic nematodes continues to accumulate; second, nematodes harm the roots, the aboveground parts mainly grow slowly, and the plants are yellow and thin, often think that it is a problem of fertilizer and water, and do not pay attention to the inspection and control of nematode diseases. Third, even if nematodes are found, frequently used pesticides do not have much effect on nematodes. In addition, the vegetable field in the greenhouse in the north provides the conditions for nematodes to survive the winter safely, which is also an important factor for its continuous rise.

How to distinguish the symptoms of nematode disease and fertilizer deficiency? Xiao Yueyan said that from the aboveground point of view, nematode disease and malnutrition are indeed difficult to distinguish, making the plant yellow, thinner, shorter, and the fruit can not mature. When making a diagnosis, you must dig out the roots and observe them. During the investigation, it was found that most of the nematodes occurred in the vegetable fields in the north were root-knot nematodes, which, as the name implies, would cause tumors on the roots of diseased plants, such as millet grains, large ones such as mung beans, round, spindle-shaped or irregular-shaped expansion, and would rot in the later stage. Maggots or other germs. But nematodes may be the first to infect plants.

Xiao Yueyan said that nematode disease is indeed not easy to control, and nematodes can tolerate many insecticides, while many pesticides that were effective in the past are prohibited because they are highly toxic to people and animals or seriously pollute the environment. For example, carbofuran, aldicarb, methyl isosalidophos, benzenophos, and so on, and some pesticides that can be used in orchards, peanuts and wheat fields, such as carbosulfan, aldicarb, methyl isosalidophos, and so on, cannot be used in vegetable fields. Therefore, we should especially strengthen agricultural and physical control, as well as develop biological control. The specific methods include: quarantine and pastoral hygiene, that is, nematodes are not allowed to spread to farmland through seeds, seedlings or soil manure, and the remains of diseased plants should be brought out and buried deeply; high-temperature stew shed is to kill nematodes at a high temperature of more than 55 ℃. The specific method is after turning the ground, sprinkle chopped rice straw or flower straw, sprinkle with raw lime water, plough about 30 cm, then pour through water and cover with film, and the greenhouse should be sealed for more than 15 days. You can kill this nematode. In the north, ploughing before winter and low temperature can also be used to kill nematodes without keeping the shed in winter; flood-drought rotation or rotation with green onion, leek, pepper, garlic and other crops; disease-resistant varieties are selected.

Xiao Yueyan pointed out that some pesticides can also be used for prevention and control. For example, before sowing, avermectin, thiazophos (10% fumigate) and other agents are used to treat the soil, and these agents can also be used to irrigate the roots of water at the initial stage of the disease. He also reminded the broad masses of peasant friends that they must pay attention to the safety of people and animals.