Control methods of common diseases and insect pests in spinach

Spinach originated in Persia and was cultivated before 2000. The main diseases and insect pests of spinach are spinach white spot, spinach Fusarium wilt, spinach downy mildew and spinach crayworm. Xiaofeng simply introduces the prevention and control methods of these common diseases and insect pests of spinach.

Control methods of white spot of spinach

The symptoms of white spot disease of spinach are mainly on the leaves. The lower leaves developed first, the lesion was round to nearly round, the edge of the spot was obvious, the size was 0.5-3.5 mm, the middle of the spot was yellow-white, the outer edge was brown to purple-brown, and gradually developed into white spot after expansion. When the humidity is high, gray hair can be seen on some disease spots, and when the dry-wet transformation is fierce, the middle of the disease spot is easy to break. This symptom is caused by Cercospora sugarbeet infection. This fungus not only harms spinach, but also harms beet and other quinoa plants, causing similar symptoms. The pathogen of spinach white spot overwintered in the soil with mycelium and spread by wind and rain in the next spring. The disease is easy to occur under weak growth, warm and humid conditions, low-lying terrain, wind and poor management.

[prevention and control methods]

The main results are as follows: 1. Select the ventilated land with flat terrain and sufficient organic fertilizer to plant spinach, properly watering and fine management to improve the disease resistance of the plant.

2. After harvest, the residual body should be removed in time and buried or burned in order to reduce the source of the disease.

3. In the early stage of the disease, spray 30% Ludabao suspension 400-500 times solution, or 1Ru 0.5 / 160 times Bordeaux solution, 75% chlorothalonil wettable powder 700 times solution, 50% mildew.

Control methods of spinach Fusarium wilt

Spinach Fusarium wilt generally occurs more seriously in the adult stage. The old leaves darkened and lost their luster, and the mesophyll gradually yellowed and expanded upward, while the roots turned brown and died when they developed downward. The plants with early onset were obviously dwarfed. When the weather is dry and the temperature is high, the diseased plants turn yellow rapidly. Under the condition of damp and low temperature, the diseased plant can survive for a period of time, and sometimes new lateral roots can grow. But in case of hot weather, it quickly withered and died.

Spinach Fusarium wilt mainly spends summer or winter in soil or seeds with plant disease residues. Seeds can carry bacteria, and so can immature manure. The bacteria can spread with Rain Water and irrigation water, invade directly from the root wound or root tip, and reach the vascular bundle after invasion. In the vascular bundle, the bacteria produce toxic substances that clog the ducts, causing the leaves to turn yellow and die. High temperature and humidity are conducive to the disease; soil temperature is about 30 degrees Celsius, soil moisture, fertilizer is not fully mature, there are many underground pests, nematodes are easy to occur.

[prevention and control methods]

1. Rotation with onion and gramineous crops for 3-5 years to avoid continuous cropping.

2. Compost retted by Japanese enzyme bacteria or fully mature organic fertilizer was applied, and formula fertilization technology was adopted to improve host disease resistance.

3. Adopt high border or ridging cultivation, drain in time after rain, and flood irrigation is strictly prohibited.

4. The diseased plant in the center was removed in time, and 50% carbendazim wettable powder, 40% polysulfide suspension, or 10% Zhiweiling water agent were sprayed every half a month for 2-3 times.

Control methods of downy mildew in spinach

Downy mildew is the most common disease in spinach. It is caused by a fungus called spinach downy mildew. The main harm symptoms in the field are as follows: the main damage leaf front, disease spot light yellow, irregular shape, different size, diameter 3-17 mm, the edge is not obvious. After the plaque was enlarged, it was connected to each other into a piece, and then turned brown and died in the later stage. A grayish-purple mildew layer is produced on the disease spot on the back of the leaf. The disease gradually developed from the outer leaves to the inner leaves and extended upward from the lower part of the plant. The diseased leaves withered and yellow during drought, rotted when the humidity was high, and the serious leaves of the whole plant turned yellow and died.

[prevention and control methods]

1. Strengthen the cultivation and management. Reasonable close planting, scientific irrigation, reduce field humidity.

2. Select disease-resistant varieties. Famous and high-quality varieties such as Savo hybrid 612, Barnti, Bonas and so on can be selected, as well as sharp-leaf varieties.

3. Collect seeds on disease-free land or disease-free plants. If the seed carries bacteria, the seed can be mixed with 50% thiram wettable powder before sowing, and the dosage is 0.4% of the seed weight.

4. if a diseased plant is found in the spinach field in early spring, it should be pulled out in time and burned out of the field.

5. In the early stage of the disease, spray 40% ethyl phosphorus aluminum wettable powder 200-250 times liquid, 58% metalaxyl aluminum wettable powder 200-250 times liquid, 58% metalaxyl manganese zinc wettable powder 500 times liquid, 64% poisonous alum wettable powder 500 times liquid, or 72.2% Prike water agent 800 times liquid, spray once every 7-10 days, 2-3 times in a row.

Control methods of Spodoptera litura in spinach

Spodoptera litura mainly harms cabbage, turnip, radish, bean, eggplant and other vegetables. The newly hatched larvae cluster on the back of the leaves to strip off the mesophyll and residual epidermis, while the older larvae disperse and nibble away at the leaves to form holes.

[prevention and control methods] generally there is no need for separate prevention and control. If the occurrence is serious, chemical control should be given priority to. The best period of spraying control is from the peak of egg hatching to the 3rd instar larvae spraying on both sides of the leaves. The agents used are: 10% permethrin EC 1000 × 1500 times, or 2.5% deltamethrin EC 2000 × 3000 times, or 20% methamphetamine EC 3000 times, or 2.5% Uranus EC 3000 times, or 10% chrysanthemum horse EC 1500 times, or 50% phoxim EC 1000 times 1500 times, etc.