We would expect forage varieties of sorghum grown in New Mexico to be most susceptible. The key will be if weather conditions allow the fungus to develop. Sorghum ergot infects plants at flowering when night temperatures are low and humidity is high. Ideal conditions for the fungus include relative humidity above 90 percent and night temperatures below 55 degrees for three to four weeks before flowering and five days after flowering. Rain and insects move fungal spores from plant to plant in the field.
Wind can carry infected plant material miles away from the original infection site.
The honeydew sticks to animals, clothing, shoes and farm equipment, making it easy to spread the disease. If sorghum ergot develops in an area, management strategies include planting resistant varieties, altering planting dates to avoid optimum weather for the fungus, and removing infected plants and weeds that can harbor the disease. Officials also are seeking permission to use preventive fungicide sprays if they are needed, Goldberg said. Because sorghum ergot is new to the United States, no fungicides currently are registered for the disease. County Extension offices throughout the state have more information about sorghum ergot.