Prevention and treatment of main diseases of spinach

Spinach wilt is generally more serious in the adult stage. It is characterized by the darkening of the old leaves, the yellowing of the mesophyll, and the upward expansion. When the development is downward, the roots become brown and die. Plants with early onset are significantly dwarfed. When the weather is dry and the temperature is high, the diseased plant quickly sallows. Under humid and low temperature conditions, the diseased plants can continue to survive for a period of time, sometimes with new lateral roots. But in the case of hot weather, it quickly died.

The spinach wilt pathogen mainly stays in the soil or on the seeds for summer or wintering with the plant disease. Seeds can be carried, and unfertilized manure can also be carried. The germ can spread with rainwater and irrigation water, directly invading from the root wound or root tip, and reaching the vascular bundle after invading. In the vascular bundle, the pathogen produces toxic substances that block the catheter, causing the leaves to sallow and die. Hot and humid in favor of incidence; soil temperature around 30 degrees Celsius, moist soil, fertilizer is not full maturity, and more underground pests, nematodes and more vulnerable to disease. Pesticide control methods:

1. Carry out 3-5 years of rotation with green onion and grass crops to avoid continuous cropping;

2. Apply compost or fully decomposed organic fertilizer prepared by Japanese enzyme bacteria, and adopt formula fertilization technology to improve host disease resistance;

3, using sorghum or ridge cultivation, timely drainage after rain, prohibiting flooding;

4, found that the central diseased plant was removed in time, the diseased point and the surrounding 50% benomyl WP 1500 times solution, 40% polysulfur suspension 500 times solution, or 10% treatment of wilting water agent 300-400 times solution, Spray once every two months for 2-3 consecutive times.

Downy mildew is the highest incidence of spinach, caused by a fungus called spinach downy mildew. The symptoms of field hazards are as follows: the main damage to the front of the leaves, the lesions are pale yellow, irregular, different in size, 3-17 mm in diameter, and the edges are not obvious. After the lesions are enlarged, they are connected to each other and become brown. A gray-purple mold layer is formed on the lesion on the back of the leaf. The disease progresses from the outer leaf to the inner leaf and extends upward from the lower part of the plant. When the drought is dry, the diseased leaves are yellow, and when the humidity is high, the leaves are rotted, and the severe whole leaves turn yellow and die. The control techniques for spinach downy mildew are as follows:

1. Strengthen cultivation management. Reasonable close planting, scientific irrigation, and reduction of field humidity.

2. Choose resistant varieties. You can use Savo hybrid 612, Barnti, Bowness and other famous varieties, as well as sharp-leaf varieties.

3. Seeding on disease-free or disease-free plants. If the seed is contaminated, it can be seeded with 50% thiram double wettable powder before sowing, and the dosage is 0.4% of the seed weight.

4. In early spring, the diseased plants are found in the spinach field. They should be removed in time and brought out to burn out.

5, in the early stage of the disease, spraying 40% ethyl phosphorus aluminum wettable powder 200-250 times liquid, 58% metalaxyl period, spraying 40% ethyl phosphorus aluminum wettable powder 200-250 times liquid, 58% metalaxyl manganese zinc Wettable powder 500 times solution, 64% antivirus WP WP 500 times solution, or 72.2% Plex water agent 800 times solution, spray once every 7-10 days, 2-3 times in a row.

The symptoms of spinach leukoplakia are mainly manifested in the leaves. The lower leaves first developed, the lesions were round to nearly round, the edge of the lesions was obvious, the size was 0.5-3.5 mm, the lesions were yellow-white in the middle, and the outer edge was brown to purple-brown. After expansion, it gradually developed into white spots. When the humidity is high, some gray spots appear on the lesions. When the dry and wet changes are fierce, the middle part of the lesion is easily broken. The appearance of this symptom is caused by the infection of the beetle. In addition to harming spinach, this fungus also harms beet plants such as sugar beet, causing similar symptoms.

The spinach leucocysts overwinter in the soil with the mycelium and the diseased debris, and the spring bacterium is spread by wind and rain. The growth is weak, and it is easy to develop under warm and humid conditions. The terrain is low, the wind is weak, and the management is not serious. Control method:

1. Choose spinach with flat terrain and sufficient organic fertilizer to plant spinach, properly watering, and fine management to improve disease resistance of plants;

2. Remove the sick body in time after harvest, concentrate on deep burial or burn to reduce the source of the disease;

3, in the early stage of the disease, spray 30% green to ensure suspending agent 400-500 times solution, or 1:0.5:160 times the amount of Bordeaux mixture, 75% chlorothalonil WP 700 times solution, 50% more mold.