The occurrence and control of root knot nematode disease in greenhouse vegetables
In recent years, due to the expansion of the area of ​​cucumbers in continuous cropping greenhouses, the disease has spread and spread, generally reducing production by 20% to 30%, severely reducing production by more than 50%, and even destroying crops. First, the characteristics of symptoms: mainly in the roots, with lateral roots and fibrous roots most vulnerable to the formation of different size and shape of the tumor roots. Some strains appeared as a string, and the nodule was white at first, soft in texture, and later turned pale brown with cracks on the surface. After the onset, the ability of the roots to absorb and transport nutrients and water drops, forming weak seedlings and affecting yield. Severe diseased plants showed slow growth, short plants and lighter leaf color. There is plenty of sunshine before and after noon, and the leaves show signs of sluggishness, which can be restored sooner or later. As the disease progresses, the leaves gradually become dry and even the plants die. Second, the conditions of the disease: In the presence of pests, soil salt content is low, suitable for nematode activity, conducive to disease, and even the incidence of greenhouse damage. Nematodes spread disease by diseased soil, diseased seedlings, and irrigation. III. Comprehensive prevention and control: The prevention and control of cucumber root-knot nematode disease in greenhouses should be based on agricultural control, supplemented by chemical control. 1, cultivate disease-free strong seedlings. Choose grain-free soil and disease-free seedling organic fertilizer preparation, nutrient soil nursery, to avoid the history of shed soil seedlings, in order to facilitate the cultivation of disease-free strong seedlings. 2, a reasonable fertilization. Replanting decomposed organic fertilizers and increasing phosphorus and potassium fertilizers can not only increase plant resistance, but also increase the natural enemies of nematodes and inhibit the growth and development of nematodes. 3, timely removal of sick bodies. For timely removal of dead plants, clean up residual roots, and bring them out of the shed for deep-buried or burned, to prevent spread of pests and diseases. It can also exterminate insects in summer. 4, pharmaceutical control. Heavily sick sheds use 10% of Acrylic Phosphorus to slowly release granules of 3 to 4 kg, while those of light diseased sheds use 2 to 3 kg. Stir 10-15 times of fine dry soil, apply a hole before transplanting, mix with soil, plant seedlings, and finally drench the water once. About 50 days after the planting of the severe disease shed, apply 10% Propyroxil Sustained-release Granules 2 to 3 kg at the acupoints and 10 to 15 cm from the plants after mixing the soil. 5, clean up the pastoral. After harvesting, the roots must be thoroughly extirpated, concentrated and brought out of the field to be buried deep or burned, and no roots should be used for fertilizers, or soiled with soil washers. 6, rotation for change. Severe patches of necrotizing diseases can be rotted with crops resistant to diseases such as peppers to reduce losses, reduce the number of nematodes in the soil, and reduce the incidence of diarrhea.