The incidence conditions and control methods of muskmelon powdery mildew!

Melon powdery mildew is one of the important diseases that harm melon production, which can cause plant photosynthetic capacity to decline, cause premature senescence, or even death, seriously affect the yield and quality of melon, spring and autumn disease is heavy, the incidence rate is relatively high, the following is to introduce the incidence conditions and control methods of melon powdery mildew!

1. Harm symptoms of melon powdery mildew

Melon powdery mildew can occur in the whole growth period of melon, mainly damaging leaves, and seriously damaging petioles and stems. At the early stage of leaf disease, white spots appeared on the front and back of leaves, gradually expanded into white circular pink spots, multiple disease spots connected with each other, so that leaves were covered with white powder. With the development of disease, the color of pink spots gradually changed to gray white. At the later stage, black spots occasionally appeared under the pink layer. Finally, the diseased leaves were withered and necrotic.

2. Conditions for the occurrence of powdery mildew of melon

Melon powdery mildew can occur at 10~25℃. Whether it can be epidemic depends on humidity and host growth. Low humidity can germinate, high humidity germination rate obviously increases. Therefore, dry or less rain after rain, but the field humidity is high, the epidemic speed of powdery mildew is accelerated. Higher humidity is conducive to spore germination and invasion. High temperature and dryness are conducive to conidia reproduction and disease expansion. Especially when high temperature and drought alternate with high humidity, and there are a large number of powdery mildew sources and susceptible hosts, the disease is epidemic. In northern China, the disease usually occurs or spreads in the rainy season or early autumn. The functional leaves around the sitting melon are most susceptible to the disease. Later, with the increase of sitting melon, the disease resistance decreases and the disease condition increases continuously.

3. Control methods of melon powdery mildew

1. agricultural control

After harvest of previous crop, remove residues of diseased plants in the field, reduce infection sources, cultivate strong seedlings, improve disease resistance of plants, apply sufficient farm manure, increase phosphorus and potassium fertilizer, prevent excessive growth and premature senescence of plants, prune branches in time, ensure good ventilation and light transmission of plants, water reasonably, and timely open sheds for ventilation and moisture discharge.

2. biological control

Before or at the beginning of the disease, use 300 million CFU/g Trichoderma harzianum leaf type, spray 300 times solution, once every 7~10 days, once every 5~7 days when the disease is severe, 95% mineral oil, Bacillus subtilis, etc. can also be used.

3. physical control

spray 80~100 times of 27% high lipid emulsion on that leaf at the early stage of disease to form a thin film on the leaf, which can not only prevent the invasion of bacteria, but also form anoxic conditions to cause the death of powdery mildew. spray once every 5~6 days for 2~3 times continuously. several days before planting, seal the greenhouse. use 250 g sulfur powder and 500 g sawdust per 100 cubic meters. mix evenly and put them into 4~5 small plastic bags. distribute them in the evening. After ignition, close the greenhouse for one night.

4. chemical control

Spray 2% agricultural antibiotic 120(pyrimidine nucleoside antibiotics) or 2% wuyimycin (BO-10) aqueous solution 200 times or Gaoke white control (ethoxystrobin), spray once every 6~7 days, or choose 45% chlorothalonil smoke agent before the onset of disease, apply 200~ 250g per mu, distribute it in the evening, after dark fire ignition, close the greenhouse for one night, and open the shed the next day.

The above is the introduction of soil drift net to the incidence conditions and control methods of melon powdery mildew, for your reference only.