Many pathogens can cause damping-off of small grains in the High Plains region, including Pythium spp., Fusarium spp., and occasionally Rhizoctonia solani. Damping-off is associated with cool (Pythium) to warm (Rhizoctonia spp.) soil temperatures and excess soil moisture. Pathogens associated with damping-off are common soil inhabitants and can survive in soil as dormant oospores or sclerotia, pathogenically on alternate hosts and weeds, and saprophytically on crop residues.
Damping-off can occur before or after small grain emergence. Pre-emergence damping-off results in a brown, gelatinous rotting within the seed coat. Radicles and cotyledons may become brown and soft after germination, but fail to emerge. Water-soaked, greasy lesions may form at the soil line and on roots after emergence when infected with Pythium spp. causing plants to collapse and wither. Post-emergence damping-off caused by Rhizoctonia solani often appears as drought or nutrient deficiencies. Rhizoctonia solani may cause brick-red to black sunken lesions that form on the coleoptiles and sub-crown internodes. Patches of seedlings can be girdled and killed.
Kodiak is registered for protection of roots from Fusarium, Rhizoctonia, and Pythium spp.
Plant high quality seed in a firm, well-prepared seedbed at optimum pH, soil temperature, and fertility level for rapid germination and growth. Avoid compaction, poorly drained fields, and excess irrigation that can favor damping-off pathogens. Crop rotation may provide some disease control, but some damping-off fungi such as Pythium spp. have broad host ranges and can survive long periods of time as oospore in the absence of a host. Tillage and burial of crop debris provides a practical control measure for Rhizoctonia solani.
Treat seed with broad-spectrum fungicides.
Product List for Damping-Off Seedling Blight:
Pesticide |
Product per 100 lbs seed |
Remarks |
Azoxystrobin |
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Protege |
0.153-0.382 fl oz |
Broad spectrum, but should be combined with Apron or Maxim |
|
Captan |
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Captan 30-DD |
1-2 fl oz |
Broad spectrum, but not effective against Pythium spp. |
|
Captan 400 |
1.5-4 fl oz |
Broad spectrum, but not effective against Pythium spp. |
|
Captan 400-C |
1.5-4 fl oz |
Broad spectrum, but not effective against Pythium spp. |
|
Carboxin: various formulations and mixtures available |
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|
Vitavax 200 Flowable |
3-4 fl oz |
Seed treatment |
|
RTU-Vitavax-Extra |
5 fl oz |
Wheat seed treatment |
|
RTU-Vitavax-Thiram |
5-6.8 fl oz |
Broad spectrum |
|
Vitavax-PCNB flowable |
5-7 fl oz |
Seed treatment |
|
Vitavax-Thiram-Lindane |
5 fl oz |
Broad spectrum |
|
Fludioxonil |
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|
Maxim 4FS |
0.08-0.16 fl oz |
Seed treatment; 30 day PHI |
|
Mancozeb: not all formulations are listed |
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|
ManKocide |
4 oz |
Broad spectrum, but not effective against Pythium spp. |
|
Manzate 75DF |
2.2-4.2 oz |
Broad spectrum, but not effective against Pythium spp. |
|
Metalaxyl |
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|
Allegiance FL |
0.75 fl oz |
Suppression of Pythium spp. |
|
Allegiance LS |
1.2 fl oz |
Suppression of Pythium spp. |
|
Apron XL LS |
0.32-0.64 fl oz |
Suppression of Pythium spp. |
|
PCNB, Metalaxyl, and Bacillus subtilis: various formulations available |
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|
PCNB 2-E Liquid |
4.2-8.4 fl oz |
Suppression of Rhizoctonia and Fusarium spp. |
|
System 3 |
2 3 oz |
Seed/planter box treatment |
|
Tebuconazole: various formulations and mixtures available |
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|
Raxil-Thiram |
3.5-4.6 fl oz |
Broad spectrum |
|
Raxil MD |
5-6.5 fl oz |
Broad spectrum |
|
Raxil MD-W |
5 fl oz |
Broad spectrum |
|
Raxil MD Extra |
5 fl oz |
Broad spectrum |
|
Raxil Xt |
0.16-0.20 oz |
Broad spectrum |
|
Thiram |
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|
42S-Thiram |
2 fl oz |
Broad spectrum seed treatment |
|
Thiram 50WP |
3.3-4.1 oz |
Broad spectrum seed treatment |
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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: Small Grains, Disease, Damping-Off, Seedling Blight
Date: 3/9/2005