Head disease of wheat
Bacterial stripe or black chaff is a bacterial disease that produces symptoms on both leaves and heads. Water-soaked lesions may develop on young leaves. These expand into reddish-brown to brownish-black streaks on the leaves. Glumes and awns show brown-black blotches or streaks. Fungicides are not effective against bacterial stripe or black chaff so the use of resistant or tolerant varieties and crop rotation are the main management options.
Take-all is one of the more common root and crown rot diseases of wheat in Missouri. The fungus which causes this disease may infect seedlings in the fall. Symptoms are usually most evident after heading as white heads on the wheat plants. Entire heads on infected plants may be bleached (white heads) and sterile. Infected plants are also stunted and slightly yellow, have few tillers and ripen prematurely. Plants with take-all typically have poorly developed root systems and roots are sparse, blackened and brittle. With sufficient soil moisture, a black-brown dry rot may extend into the crown and up the lower stem.
This shiny, black discoloration of the lower stem and crown may be seen if the lowest leaf sheath is scraped off with a knife or fingernail. A management program for take-all should including planting good quality seed of adapted, disease resistant varieties, planting in well-drained sites under good seed bed conditions, rotating with nonhost crops for one to three years, controlling weed-grass hosts and volunteer wheat, using seed treatment fungicides and maintaining good plant vigor with adequate fertility.
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