This season the NWCS team is interested in collecting smut infected grain heads with a goal of identifying all smut disease that are present in the Northeast. We are looking for farmers to notify us if they spot smut in their small grain fields. Smuts are one of the easiest grain diseases to spot in the field (Image 1. Loose smut infected wheat head, Burlington, VT).
As winter and spring grains begin to head out and flower, you can start to see the visual signs of smut. There are several types of the smut pathogen found in the Northeast: Loose smut (Wheat = Ustilago tritici / Barley = U. nuda), False loose smut (Barley = U. nigra / Oats = U. avenae), and Covered smut (Barley = U. hordei).
Loose smut: During spike or head emergence, diseased heads emerge slightly earlier than healthy ones and appear as a mass of dark brown spores covered with paper-like membrane. This membrane tears easily as healthy plants begin to flower, and windblown spores infect the embryos of developing seed. After the fungus invades the grain seed embryo, it remains dormant until the seed is planted and germinates. Infected plants appear to be normal, but develop smutted heads.
Covered smut: Infected plants are often stunted and heads may not completely emerge. During spike or head emergence, diseased heads emerge at the same time, or slightly later than healthy ones and appear as mass of dark brown spores covered with paper-like membrane. This membrane ruptures at plant maturity or during threshing, and the spores infect healthy seed and soil. Covered smut spores are not typically wind-dispersed. The fungal spores remain dormant on seed coat until the seed is planted and germinates. Infected plants appear to be normal, but develop smutted heads.
Planting contaminated seed, especially in organic systems, can exponentially increase grain infection rates, resulting in yield reductions; 100% of the smutted heads are lost. Eating smut infected grain poses no harmful health effects and doesn’t appear to impact baking quality.
Control
- If you find smutted heads in your fields, do not save the seed.
- Plant certified or otherwise high-quality, disease-free seed.
- Plant resistant varieties.
- Infected seed can be treated with various fungicides in conventional systems.