Foot rot, crown rot, and wirestem are caused by the fungus Rhizoctonia solani. Diseases caused by R. solani are associated with warm soil temperatures, excess soil moisture, and delayed seedling emergence. Wirestem develops when the fungus invades the cortical tissue and girdles young stems. Plants remain alive and continue to grow slowly, but give rise to spindly plants. R. solani can survive in soil as sclerotia, pathogenically on alternate hosts and weeds, and saprophytically on crop residues.
Foot rot causes premature ripening of plants. Infected plants are found singularly or in patches. Hard, clearly defined, brown to red lesions are found on diseased stems near the soil line. A severe infection causes a girdling and kills plants. The crown rot disease caused by R. solani induces necrotic lesions on leaves and eventual defoliation. Wirestem symptoms appear as reddish brown to black, sunken lesions that form on cortical tissue and stems. Large lesions may girdle the stem and kill the plant, or produce a spindly, stunted, and yellow plant.
Deny (Burkholderia cepacia) is registered for protection of roots from Fusarium, Rhizoctonia, and Pythium spp., but its efficacy in the High Plains is unknown.
Encourage rapid seed germination and vigorous growth of seedling by planting high quality seed in warm, firm, well-prepared seedbeds. Early plantings tend to be affected by crown rot more than later plantings. Provide adequate but not excessive fertilization to promote vigorous growth of seedlings. Avoid planting into cold soils, excessive irrigation, poor drainage, and compaction. Ensure crop residues from the previous crop are thoroughly decomposed before planting. Crop rotation with non-hosts (i.e., small grains) may provide some reduction in foot rot and wirestem. Control volunteer canola, mustard, and weeds in and around fields.
Fungicides are most effective when used in combination with cultural control strategies.
Product List for Foot Rot, Crown Rot, and Wirestrem:
Pesticide |
Rate per 100 lb seed |
Application Frequency (days) |
Remarks |
|
Captan |
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|
Captan 75 |
6-9 oz |
Seed treatment |
Broad spectrum, but weak against Pythium and Phytophthora spp. |
|
Captan 30-DD |
1.25 fl oz |
Seed treatment |
Broad spectrum, but weak against Pythium and Phytophthora spp. |
|
Captan 400 |
1-2 fl oz |
Seed treatment |
Broad spectrum, but weak against Pythium and Phytophthora spp. |
|
Captan 400-C |
1-2 fl oz |
Seed treatment |
Broad spectrum, but weak against Pythium and Phytophthora spp. |
|
Fludioxonil |
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|
Maxim 4FS |
0.08-0.16 fl oz |
Seed treatment |
Suppression of Fusarium and Rhizoctonia spp. |
|
Thiram |
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|
42-S Thiram |
8 fl oz |
Seed treatment |
Broad spectrum |
|
Thiram 50WP |
8 oz |
Seed treatment |
Broad spectrum |
|
The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality. |
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Categories: Canola and Mustard, Disease, Foot Rot, Crown Rot, Wirestem
Date: 12/30/2004