by Glenn Shewmaker, Extension forage specialist (gshew@uidaho.edu); Oliver Neher, Extension Plant Pathologist (oneher@uidaho.edu); Mireille Chahine, Extension Dairy Specialist (mchahine@uidaho.edu); and Benton Glaze, Extension Beef Specialist (bglaze@uidaho.edu); University of Idaho
Weather conditions prior to, during first cutting, and while making hay have been very moist. Many areas have 2 or more inches of above normal precipitation. Much hay has been rained on or left lying in the field for prolonged time periods due to cool and humid conditions which reduced drying rates. The long drying periods with high humidity allowed field growth of mold on the hay. We will try to state some facts and offer some recommendations for hay producers and livestock producers. What is the "black dust" that covers my mower or swather?
• The black dust is most likely spores produced by fungal organisms. Spores are how the fungi reproduce and are always present but usually at lower concentration. The black dust on a mower or swather indicates that fungal growth was present prior to cutting.
