For Sclerotinia rot, generally apply 4-5 kg of 50% carbendazim wettable powder per mu, mix thoroughly with an appropriate amount of dry soil and spread it on the bed surface, then rake it into the soil, which can reduce the primary infection source. At the early flowering stage, you can use a 500-fold dilution of 70% mancozeb wettable powder; a 1000-fold dilution of 70% thiophanate-methyl, 50% carbendazim or 40% validamycin wettable powder to spray the stem base, old leaves and ground surface of the plants; start applying the fungicide at the early stage of disease onset, once every 7-10 days, and 2-3 consecutive sprays can achieve effective control.
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<p style="text-indent:2em;"><span style="color:#FF0000"><strong>1. What symptoms does Sclerotinia rot have?</strong></span></p>
<p style="text-indent:2em;">At the seedling stage, red-brown spots appear on the affected stems and leaf stalks, and later they expand and turn white. If the disease occurs at the leaf stage, the leaf margins of the old leaves at the base of the plant are the first to be affected.</p>
<p style="text-indent:2em;">The lesions initially appear dark blue-green and water-soaked, and later expand into round or irregular large spots. The center of the lesion is yellow-brown, and the surrounding area is light yellow. Sometimes the outline pattern on the lesion is relatively obvious. In dry weather, the lesion will crack and perforate; in rainy weather, the lesion will expand rapidly and the whole leaf will become rotten.</p>
<p style="text-indent:2em;">If the disease occurs on the stem, the pathogen generally appears on the middle and lower parts of the main stem. The lesion initially appears light brown and water-soaked, and later gradually develops into an oval shape. Under humid conditions, the lesion expands rapidly. In the late stage of disease development, the cortex splits longitudinally, and the root stem becomes extremely easy to break.</p>
<p style="text-indent:2em;"><span style="color:#FF0000"><strong>2. What is the disease pattern of Sclerotinia rot?</strong></span></p>
<p style="text-indent:2em;">The pathogen of Sclerotinia rot is Sclerotinia sclerotiorum. The sclerotia are round or irregular in shape, white at first and black later, and the interior of the pathogen is grayish white. The pathogen has a very wide host range. Besides rapeseed, it also affects many other crops such as sunflower and carrot.</p>
<p style="text-indent:2em;"><span style="color:#FF0000"><strong>3. How to control Sclerotinia rot?</strong></span></p>
<p style="text-indent:2em;">1. Agricultural control:</p>
<p style="text-indent:2em;">(1) Develop disease-resistant varieties: cultivate high-yield, disease-resistant improved varieties according to local conditions.</p>
<p style="text-indent:2em;">(2) Seed disinfection: through screening, chemical seed soaking and other methods, eliminate sclerotia and kill bacteria on the seed surface, and sow disease-free seeds.</p>
<p style="text-indent:2em;">(3) Timely remove diseased residues: after harvesting the crop, promptly burn and clear the diseased residues in the field and beside the roads to reduce the source of the pathogen.</p>
<p style="text-indent:2em;">2. Chemical control:</p>
<p style="text-indent:2em;">Use special-effect fungicides such as prochloraz and Shibaike for protective treatment. The best application period for prochloraz is from the full flowering stage to the late full flowering stage.</p>
<p style="text-indent:2em;">The above is a detailed introduction to what fungicide to use for Sclerotinia rot and its disease symptoms. I hope it is helpful to everyone.</p>
For Sclerotinia rot, generally apply 4 to 5 kg of 50% carbendazim wettable powder per mu, mix it thoroughly with an appropriate amount of dry soil, spread it evenly over the bed surface, and then rake it into the soil to reduce the source of primary infection. At the early flowering stage, you can use a 500-fold dilution of 70% mancozeb wettable powder; or a 1000-fold dilution of 70% thiophanate-methyl, 50% carbendazim or 40% validamycin wettable powder, spraying the base of the plant stems, the old leaves and the ground surface; start applying the chemicals at the early stage of disease onset, once every 7 to 10 days, and 2 to 3 consecutive sprays can effectively control it.
1. What are the symptoms of Sclerotinia rot?
At the seedling stage, reddish-brown spots appear on the affected stems and leaf stalks, and later they expand and turn white. If the disease occurs at the leaf stage, the leaf margins of the old leaves at the base of the plant are the first to be affected.
The lesions initially appear dark bluish-green and water-soaked, and later expand into round or irregular large spots, with the center of the lesion appearing yellowish-brown and the surrounding area light yellow. Sometimes the outline pattern on the lesion is fairly obvious. In dry weather, the lesion will crack and perforate; in rainy weather, the lesion expands rapidly and the whole leaf becomes rotten.
If the disease occurs on the stem, the pathogen generally appears on the middle and lower parts of the main stem. The lesion initially appears light brown and water-soaked, and later gradually develops into an oval shape. Under moist conditions, the lesion expands rapidly, and by the late stage of disease development, the cortex splits lengthwise and the root and stem become extremely easy to break.
2. What is the pattern of occurrence of Sclerotinia rot?
The pathogen of Sclerotinia rot is Sclerotinia sclerotiorum. The sclerotia are round or irregular in shape, white at first and turning black later, while the interior of the pathogen is grayish-white. The pathogen has a very wide host range; besides rapeseed, it also affects many other crops such as sunflower and carrot.
3. How to control Sclerotinia rot?
1. Agricultural control:
(1) Develop disease-resistant varieties: cultivate high-yielding, disease-resistant improved varieties suited to local conditions.
(2) Seed disinfection: through methods such as screening and soaking seeds in chemicals, eliminate sclerotia and kill bacteria on the seed coat, and sow disease-free seeds.
(3) Promptly remove diseased plant debris: after harvesting the crop, promptly burn and clear away the diseased plant debris in the field and along roadsides to reduce the source of the pathogen.
2. Chemical control:
Use specific-effect chemicals such as prochloraz and Shibaike for protective treatment. The best time to apply prochloraz is from full flowering to the end of full flowering.
The above is a detailed introduction to what chemicals to use for Sclerotinia rot and its disease symptoms. We hope it is helpful to everyone.