Control methods of Sclerotinia sclerotiorum of Cucumber with Fruit Rot and long White mycelium

Cucumber Sclerotinia sclerotiorum, also known as rotten tip disease, cucumber in open field and protected field can occur, and the disease in protected land is the most serious. The general loss is 10% to 30%, serious parcels, up to more than 90%, resulting in no production. Low temperature, high humidity or rainy early spring is the high incidence season of cucumber Sclerotinia sclerotiorum, so the prevention and control should be strengthened.

Cucumber Sclerotinia sclerotiorum

Symptoms:

It can occur from seedling stage to adult stage, which not only harms melons and fruits, but also harms stems, leaves, flowers and other parts. Melon and fruit damage, first produce waterlogged irregular disease spots in the residual flowers, and then the cucumber tip becomes soft and rotten, cotton-like white mycelium grows on the rotten cucumber surface, and black mouse fecal sclerotia. Most of the stem vines were damaged in the middle and lower part of the main stem, and waterlogged light brown spots were produced at the bifurcations of the main and lateral branches, which were slightly sunken and then turned white. under the condition of high humidity, the diseased stem soft rot, white cotton hairy hyphae, stem vines and leaves above the damaged parts withered to death, and finally the pith of the stem was destroyed by bacteria and hollow, and produced white hyphae and mouse fecal sclerotia.

Integrated prevention and control:

1. Agricultural prevention and control. Rotation with aquatic vegetables, Gramineae, onions and garlic every other year. After harvest, thoroughly remove the disabled body, take it out of the field, bury it deeply or burn it. When the soil was turned over 25cm, the sclerotia was buried in the deep layer to inhibit the emergence of ascomycetes. The diseased site can be immersed in irrigation for more than 10 days in summer to promote sclerotia rot. The formula fertilization technology was adopted to enhance the disease resistance of cucumber.

two。 Physical control. Before sowing, the seeds were bleached with 10% salt water for 2 or 3 times to remove sclerotia. The use of ultraviolet greenhouse film can hinder the unearthing of ascomycetes and the formation of ascospores. The cultivation method of high border covered with plastic film can also be used to reduce the source of bacteria.

3. Disinfect seeds and soil. Before planting, 40% pentachloronitrobenzene was mixed into medicinal soil, raked into the soil, 1 kg / mu of medicine was mixed with 20 kg of fine soil, mixed well and sprinkled into the planting hole; the seeds were soaked in 50 ℃ warm water for 10 minutes to kill the sclerotia in the seeds.

4. Ecological control. When growing in the greenhouse, the temperature should be closed in the morning, the temperature should not exceed 30 ℃, and in the afternoon, the air should be released and the moisture should be drained. Cucumber can appropriately increase the night temperature to reduce the dew time. The average daily temperature in early spring is 29 ℃ or 31 ℃, and the relative humidity is less than 65%. To prevent excessive irrigation, when the soil moisture is high, the irrigation interval can be prolonged.

5. Prevention and cure of smearing on stem. When the stem is infected with Sclerotinia sclerotiorum, you can first use a blade to scrape off the rot of the diseased stem long white hair, and then dilute 50% Sukeling or prohydantoin water to 20% 30 times the liquid, such as thick milk paste (you can also mix a small amount of edible starch paste and powder at 2:1 with water), smear the affected area, usually after one application, the patient will slowly heal itself, and the cucumber can continue to blossom and bear fruit. If the patient is seriously rotten, apply it again 3-5 days later, depending on the condition. Usually, cucumber plants with diseased stems rotting less than half of their diameter can be saved and a certain yield can be maintained.

6. Chemical control. In the early stage of cucumber disease, 250 grams of 10% Chlorothalonil smoke agent per mu or 45% chlorothalonil smoke remover was fumigated for one night, once every 8-10 days, continuously or alternately with other methods for 3-4 times; spray 5% chlorothalonil dust agent, about 1 kg per mu each time It can also be sprayed with 1000 times of 50% Nongliling wettable powder or 60% Fangmaibao ultra-fine powder or 1000 times of 50% prohydantoin wettable powder or 1000 times of methyl topiramate, once every 7 days and 4 times in a row.