Farmers who grow melon crops know that melon crops are prone to powdery mildew, also known as white powder and mildew. In particular, melon, zucchini, pumpkin, cucumber, etc. are more likely to be milder and more common. If not treated in time, it will seriously affect the growth and development of melon crops. Seriously, it will lead to premature aging of the crops. Farmers cause certain economic losses. Then what are the symptoms and pathogenesis of powdery mildew in melon crops? How to prevent it?
1. Symptoms of powdery mildew in melon crops
The disease mainly affects crop leaves, petioles, stems and vines, and the fruit is often damaged. In the early stage of powdery mildew, small round white powdery mildew spots grow on the front or back of the leaves, and gradually expand into larger white powdery mildew spots, which later spread to the petioles and stems and even tender fruits. In severe cases, the whole plant leaves are covered by white powdery mildew, and the leaves turn yellow and brown, and the texture becomes brittle. Later in the late stage, there are scattered or piled off-season closed capsules in the white powder layer, which turns yellow into black-brown small spots.
2. The incidence of powdery mildew in melon crops
The disease is caused by fungal infiltration, and the pathogen can overwinter on the diseased body and winter on the greenhouse crop. Pathogens are transmitted by means of airflow, rainwater, and farming operations.
3. Prevention and control measures for powdery mildew of melon crops
(1) Sterilization of the shed. 5 to 7 days before planting, 250 grams of sulphur powder can be used in each half-acre shed, and mixed with 500 grams of dry sawdust, then packed in several plastic bags or pots, placed in the shed, in the evening, The closed shed film was ignited for one night and the wind was enlarged the next day. When fumigation, the indoor temperature in the shed is best maintained at around 20 °C, and the poles and the like can also be placed in the shed and disinfected at the same time.
(2) Seed selection. Choose a variety of melon resistant to powdery mildew
(3) Prevention by physical law. In the early stage of the disease, a high-fat membrane can be used, sprayed with 30 to 50 times of water, sprayed once every 7 to 10 days, even sprayed 4 times, and sprayed 50-75 kg per acre.
(4) Prevention and control of baking soda. In the early stage of the disease, spray with 0.2% baking soda solution. Spray once every 7 to 9 days, spray 75 kg per acre.
(5) Biological control. Use agricultural anti-120, water 200 times liquid, spray at the beginning of the disease. Spray once every 7 days, even spray 2 to 3 times, spray 75 kg per acre.
(6) Chemical control. In the production, it is recommended to spray the drug 15 days in advance in the normal year. You can use 10% difenoconazole microemulsion 900-1000 times solution or 25% ethyl pyrimidine powder suspension 800-1000 times solution, once every 10 days. . At the initial onset, use 25% pyraclostrobin emulsion 1500 times solution, or 20% triazolone emulsifiable oil 1500 times solution, or 25% triazolone wettable powder 2000-3000 times solution, or 20% zolapril suspension 800-1000 times the solution, spray once every 7 to 9 days, even spray 2 to 3 times. Note that when using the medicine, it must be strictly used according to the dosage and the guidance method to avoid the phytotoxicity. In addition, the melon seedling stage is sensitive to the azole medicine, and should be used in half.
(7) Control of smoke agents. Each season, 10% chlorothalonil smoker 300-400 grams, or 45% chlorothalonil smoke agent 250 grams, or 300 grams of powder rusting smoke agent, fumigation at the initial onset.
The above symptoms, pathogenesis and control measures of powdery mildew in melon crops, melon powdery mildew is a common disease of melon crops, and the distribution is also extensive, so farmers must pay attention to prevention and control in the process of planting melon crops. To avoid the impact on powdery mildew and affect the yield and quality of melon crops, I hope the above can help farmers.
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