University of Illinois

No. 6/May 2, 1997

Potential Soybean Diseases for 1997

At a recent meeting of plant pathologists from the north-central region(roughly Ohio to Nebraska), a disease-loss summary was developed for themajor diseases found in this region. The top five diseases or disease complexesfor 1996 were

1. Soybean cyst nematode
2. Brown stem rot
3. Phytophthora root rot
4. Sclerotinia white mold
5. Seed and seedling blights

It is interesting to note that of these top five diseases, four (brownstem rot, Phytophthora root rot, Sclerotinia white mold, and seed and seedlingblights) are most damaging in wet and cool soils. The adoption of reducedtillage practices and earlier planting of soybeans may be changing the diseasepicture throughout this region. Only SCN seems to be unaffected by soilconditions, as long as temperatures are warm enough in the early springto hatch the eggs. Predictions were that white mold, a relatively recentdisease in this state, probably will surpass Phytophthora root rot withina year or two in terms of yields and economic loss to soybean producersin the north-central region.

Suggested Seed Treatments and Diseases Controlled

 Diseases controlled Common name Product name of fungicide Comments
 PythiumOxadixylAnchorSuppresses Phytophthora
Rhizoctonia and other seedling blightsPNCBPNCB 
  Thiabendazole (TBZ) ManyControls Phomopsis (pod and stem infections)
  Maneb + CaptanGranox P-F-M 
  Chloroneb + MetalaxylNu-Flow ADControls Pythium/Phytophthora
  TBZ + CaptanMany 
  ChloronebChloroneb 65W 
  Thiram + CarboxinMany 
  Bacillus SubtillisKodiakUse with a chemical seed treatment
  Other biologicalsMany 

H. Walker Kirby, Departmentof Crop Sciences, (217)333-4424