PPFS-AG-SG-1



	<H1><CENTER>TAKE-ALL OF WHEAT</CENTER></H1><BR>




	<H3>Donald Hershman and Paul Bachi</H3>				(Revised 7-94)<BR>






	"Take-all" is the common name of a root, crown and foot rot of wheat caused by the soil-borne fungus Gaeumannomyces graminis var tritici. This disease has become more important in recent years as the cropping of wheat has increased. Take-all is most likely to occur in early seeded wheat and when plants are under nitrogen stress. The disease is most common where wheat is grown continuously or without adequate rotation, but it can occur in wheat the first year out of sod. The fungus is not seed-borne.<BR>




<H4>SYMPTOMS</H4><BR>


	Initially, infected plants may appear slightly stunted and off-color in the fall or early spring. Frequently these early symptoms go unnoticed or they may be confused with many other conditions, such as problems related to nutrition or soil moisture. However, an examination of the stunted root system reveals brownish-black lesions which distinguishes take-all from other problems. The most obvious symptoms, however, occur about the time of heading and thereafter. Infected plants die prematurely, generally within circular patches in the field. These plants appear bleached or straw-colored prior to normal maturity. Tillering is also reduced, frequently resulting in only one head per plant or, under severe conditions, none. The main roots, crown and basal culm tissue show a dry rot. This is accompanied by a dark- brown to black surface mat of fungus tissue underneath the leaf sheath at the base of the plants.



<H4>CONTROL</H4><BR>


	Resistance is not available in currently grown varieties of wheat. Control involves the use of several cultural practices.<BR>




	<B>1.	Crop rotation</B> - Take-all is more severe where wheat follows wheat. Crop rotations of 2-4 years with corn or soybeans are recommended. Rotation will reduce the incidence of take-all but it will not eliminate it. The fungus can survive on a number of other crops such as barley, oats, rye, many grasses, etc., even though in some instances symptoms may not be noted. Take-all has not caused problems in oats or barley in Kentucky to date.<BR>



	<B>2.	Nitrogen fertility</B> - More severe symptoms are usually found on plants under nitrogen stress. Split applications of nitrogen in fall and spring may reduce damage from take-all. Longer lasting nitrogen sources applied in the fall may reduce the incidence of disease. High pH, low levels of phosphorus and fast release forms of nitrogen (i.e. nitrate nitrogen) are favorable to take-all.<BR>


	<B>3.	Sanitation</B> - Clean plow down of wheat residue after harvest should reduce disease incidence by providing more rapid decomposition of residue.<BR>


	<B>4.	Date of planting</B> - Early fall planting usually leads to more severe take-all problems. Warmer soils during seedling growth apparently increases the incidence of early infection. Plant as late as practical in the fall and no deeper than necessary.