What are the symptoms of Sclerotinia sclerotiorum? What is the method of prevention and control?

We all know that cantaloupes produced in Xinjiang are big and sweet because they are exposed to light for a long time. However, now delicious cantaloupe is not only available in Xinjiang, but also grown everywhere. In the process of planting Hami melon, diseases will occur due to some reasons, especially Sclerotinia sclerotiorum, which has an impact on the yield and quality of Hami melon. What are the symptoms of Sclerotinia sclerotiorum? What is the method of prevention and control?

First, what are the symptoms of Sclerotinia sclerotiorum?

The disease began at the base of the seedling stage, the disease part was light brown in water immersion, white flocculent mold (hyphae) grew when the humidity was high, it was soft rot, gray-white after drying, the disease part constricted, and the seedlings withered.

In the adult stage, the leaf infection begins at the leaf edge, showing a water stain at the beginning, light green, a small amount of white mold grows when the humidity is high, the disease spot is grayish brown, spreads quickly, and the diseased leaves wither and die. Stem infection is mostly invaded by the base of petiole, the spot is gray and slightly sunken, in the later stage, the epidermis is longitudinally split, the pith is destroyed and hollow, the common stem surface forms sclerotia, peeling off the stem can find a large number of sclerotia, when the disease is serious, the plant dies.

When the fruit is infected, oily patches are formed from the pedicel, then turn into dark green round depressions, and gradually expand, and the diseased part is covered by a large number of cotton-like hyphae, accompanied by irregular black particles.

Second, what is the prevention and control method of Sclerotinia sclerotiorum in Hami melon?

The main results are as follows: 1. Apply fully mature organic fertilizer, deep ploughing and ploughing the field and sulk the shed at high temperature. The highest temperature in the shed reached more than 60 ℃, killing organic fertilizer and sclerotia in soil. Deep ploughing can make the sclerotia buried in the lower half of the plough layer, so that the sclerotia can not germinate.

2. Bleach the seeds with 10% brine for 2 or 3 times before sowing, remove the sclerotia, or use ultraviolet plastic film in the plastic shed to inhibit the formation of ascomycetes and ascospores. High border mulching film can also be used to inhibit the release of ascospores unearthed from ascomycetes and reduce the source of bacteria.

3. Cultivate disease-free seedlings and cover plastic film after planting to prevent seedling from spreading the disease. Plastic film can be used to inhibit sclerotia germination and ascus unearthed.

4. Strengthen the control of temperature and humidity in the greenhouse to reduce humidity and temperature, and reduce the spread of sclerotia and ascospores. It is mainly to raise the temperature in the stuffy shed in the morning, release air and drain moisture in the afternoon, appropriately increase the night temperature to reduce dew, the daily average temperature in early spring is controlled at 29 ℃ or 31 ℃, and the relative humidity below 65% can reduce the incidence of the disease, prevent excessive watering and prolong the watering interval when the soil moisture is high.

5. Use aerosol and dust to prevent and cure. At the beginning of the disease, 250g / 300g of 10% Sukeling aerosol was used in the early stage of the disease, and it was sealed for one night after smoking in the evening, or 5% chlorothalonil powder 1kg could be sprayed on 667m2 in the evening, once every 7 to 8 days.

6. Spraying chemicals. In full bloom or early stage of the disease, 50% Nonglieling or Sukeling wettable powder 1000 × 1500 times or 40% sclerotiorum 1000 × 1500 times; 50% carbendazim wettable powder or 50% topiramine 500 times, once every 5 to 7 days for 3 times in a row.