-3- 



For control: (1) rotate wheat ground every year. (2) Plow wheat stubble soon 

 after harvest. This may not be possible when double-cropping is used or when 

 erosion control is necessary. (3) Destroy all volunteer wheat before seeding 

 time. (4) Plant treated, cleaned, and certified wheat seed. (5) Do not spread 

 leaf -spot infected straw manure on wheat ground. (6) If possible, select late- 

 maturing wheat varieties that are less susceptible than the early-maturing vari- 

 eties. No wheat variety is resistant to leaf spot . (7) Apply 1.6 pounds of Maneb- 

 plus- zinc- ion (Di thane M45 or Manzate 200) to control leaf spot on wheat, oats, 

 rye, and barley. Begin applications when the crop is in the jointing stage. Mix 

 the fungicide in sufficient water to provide adequate coverage. Repeat applica- 

 tion at ten-day intervals, but do not make more than three applications during a 

 season. Do not apply within 26 days of harvest and do not graze livestock on 

 treated fields for at least 26 days after application. Speckled- leaf spot fungi- 

 cide applications are not usually economical unless the disease level is very 

 high early in the season. Maneb-plus-zinc-ion also controls rust and Helmintho- 

 sporium diseases when properly applied at the right time. 



Rot and crown rots are most likely to develop in cool, wet soils- -especially in 

 fields where alternate freezing and thawing have caused heaving, injuring the 

 roots and crowns of the plants. Some plants may be weakened and killed. Others 

 may recover in warm, dry weather. But yields will be lower in terms of both quan- 

 tity and quality. 



Losses from root and crown rots are usually the greatest in moist soils where small 

 grains and grasses are grown more or less continuously. Single plants may be af- 

 fected, all the plants in small circular- to- irregular patches, or all the plants 

 in large areas within a field. 



Root and crown diseases are caused by many species of seed- and soil-borne fungi. 

 Microscopic examination and laboratory culturing are usually necessary to deter- 

 mine the exact cause of root or crown rot. Two or more fungi are often associated 

 with the disease on a single, affected plant. 



There is little that can be done for small grains already in the field. If you 

 are planting spring oats, barley, or wheat now, get high-quality seed; use a 

 fungicide seed treatment; and plant in a fertile, well -prepared, well-drained 

 seedbed at the time recommended for your area. Plant no deeper than necessary 

 to provide sufficient moisture for good germination and emergence. Rotate small 

 grains with soybeans and forage legumes. Where practical, plant resistant vari- 

 eties. 



For more details, see the Illinois Agronomy Handbook 1975, and Report on Plant 

 Diseases No. 113, "Root Rots of Small Grains." 



The common plant diseases that have attacked Illinois field crops, vegetables, 

 fruits, turf, and ornamental plants during the past are likely to be present again 

 this year. But whether the diseases develop and to what extent depends on the 

 proper combination of (1) weather conditions, (2) the availability of susceptible 

 plants, and (3) the presence of infectious agents (pathogens). 



Weather conditions include sunlight, rainfall and humidity, temperature, wind, and 

 atmospheric pressure. Any one, or some combination, of these elements may affect 

 the occurrence of disease. 



