Control of Sclerotinia sclerotiorum in rape

Sclerotinia sclerotiorum, also known as rotten stem disease, is a fungal disease. Its harm lasts for a long time and can occur from emergence to maturity, especially after flowering. The main results are as follows: 1. After being infected at the seedling stage, reddish-brown spots appear at the base of the stem and petiole, then expand and turn to white, there are white flocculent hyphae above the rot, and finally the pathogen dies, and many black sclerotia are formed outside the diseased tissue. 2. The main symptoms from budding to maturity are round or irregular spots on the leaves, grayish brown in the center, dark cyan in the middle, and black halos in the periphery. 3. In the later stage of the disease, the stem became empty, the cortex was ruptured, the vascular bundle was exposed like hemp, and the stem of the diseased plant was easy to crack and break with green dung-like black sclerotia. After the flower is sick, the color is pale, has no luster, and is easy to fall off. After the pod is damaged, irregular white spots are produced, there are sclerotia inside, and the seeds are dried up. Control methods: 1. Crop rotation: because Sclerotinia sclerotiorum is a soil-borne disease, the pathogen mainly exists in the soil, so it is best to rotate with rice. Because sclerotia will rot after soaking in water for 1 to 2 months, if it is a dry land rotation, it will take more than three years to eliminate Sclerotinia sclerotiorum. 2. Selection of disease-resistant varieties: varieties with high yield and disease resistance should be selected. 3. Seed treatment: rinse with 10% brine solution, remove the floating blighted grains and sclerotia, wash the sunken seeds with clean water to dry and sow. 4, clear ditch drainage 5, chemical control: mainly in the early flowering stage for spray control, can choose 40% of the sclerotia net or carbendazim spray, spray as far as possible in the middle and lower part of the plant.