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AgAlerts 2005 From Griggs County
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Issue # 3, July 14, 2005
Samples of wheat and barley have been brought with ergot infestations. Ergot is not a major disease but in some years we see increased incidence of infection. Ergot will appear as purple to black sclerotia that has replace the seed in the head. Most times the ergot sclerotia will be longer than the grain kernel but can also be the same size. Ergot can infect a variety of grasses and cereal crops. The sclerotia bodies will fall to the ground and overwinter producing spores the following year that will be the source of infection. The spores from the sclerotia are wind blown and find their way into the flowering floret of the particular cereal. Once the floret is infected the fungus will produce a yellow-white sticky liquid (honey dew) that is attractive to insects. Spores produced in this liquid will be carried to other plants by the insects causing the disease to spread. Spores may be transferred to other heads via rain splash or direct contact. Once the fungus is established it will grow throughout the embryos eventually producing the sclerotia bodies that will over winter to start the disease cycle over again.
Control of ergot involves planting ergot free seed, controlling grasses adjoining fields prior to them flowering, crop rotation, deep plowing to bury scelortia bodies and planting resistant varieties.
Ergot can be toxic to livestock in four ways. An acute form characterized by convulsions, a chronic form characterized by gangrene, hyperthermia (increased body temperature) in cattle and agalactia (no milk) and lack of mammary gland development, prolonged gestations, and early foal deaths in mares fed heavily contaminated feed. For more information on ergot or danger to animals, consult NDSU Extension bulletin, PP-551, Ergot.
There has been some reports from the Casselton area of HRSW having bacterial stripe (blight) infects. This disease was favored by the driving rains over the past couple of weeks. Now with the hot dry weather, the leaves are turning brown. The lesions are a mid-brown, striped or longitudinal along the leaf veins. In the northern part of the state the variety Granite is showing these symptoms. Severity of bacterial stripe will depend on frequency of rains and rain storms and variety. Bacterial stripe lesions are distinct from Septoria lesions, which are often more oval and have a dull to slightly powdery appearance, with fruiting bodies in the middle of the lesion sometimes visible. Fungicides do NOT control bacterial infections, so bacterial stripe can show up in fungicide treated fields.
Brown spot is a disease that is favored by wet weather. Symptoms of the disease are small, dark brown, irregular spots with or without a yellow halo. Lesions may enlarge and coalesce, and frequently they are concentrated along the leaf veins or at the leaf margin. The disease decreases with warm, dry weather. The past two weeks have been ideal conditions for this disease. The following pictures show some of the symptoms of this disease. Notice the leaf damage due to the break out of the diseased areas of the leaves. There is no treatment for control of this disease other than crop rotation or tolerant cultivars. Click on the following link for a picture of septoria brown spot.
Please Contact Our Office For Additional Information
E-mail: john.swenson@ndsu.edu
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