Black stem rust is a fungal disease of cereal crops caused by Puccinia graminis. It has historically caused devastating yield losses in wheat and other small grains worldwide but is now largely controlled through resistant cultivars and regulatory programs. It infects wheat, barley, oats, rye, timothy, orchardgrass, fescue, ryegrass, and related grasses. The fungus may also infect alternate woody shrub hosts in the genera Berberis, Mahonia, and hybrid Mahoberberis (barberry plants). The disease is present worldwide and can occur anywhere susceptible cereal plants grow.
On Cereal Crops
- Early infection: reddish-brown, elongated rust pustules (uredinia) on stems, leaf sheaths, leaves, and sometimes the heads of wheat and other cereals.
- Late season: black, hardened spores (teliospores) form on lesions — giving the disease its common name black rust.
- Severe infection can weaken stems, reduce grain fill, and lead to lodging or significant yield loss.
On Barberry and Related Shrubs
- On alternate hosts (Berberis/Mahonia): small rust pustules or yellow/orange sporulating structures appear on leaves and stems. Spores form that can infect cereal hosts.
Note: Many rust diseases affect grasses; accurate identification is essential. If unsure, collect a sample and submit to a diagnostic lab or your local DNR inspector.
Although severe epidemics are uncommon today due to resistant cereal cultivars and federal eradication programs, the pathogen can still be present and has potential to impact both crop production and nursery stock movement.
State Regulations — Indiana
Under 312 IAC 18-3-8, the importation, interstate movement, and control of certain rust-susceptible and rust-resistant barberry species and related shrubs is are regulated:
- Rust-susceptible species of Berberis, Mahoberberis, and Mahonia (except decorative cuttings of Mahonia) are prohibited from entering or moving through Indiana without an appropriate USDA-APHIS permit.
- Regulated plants (including some rust-resistant varieties) must be inspected and accompanied by required certificates as outlined in federal quarantine regulations.
- All nursery stock, plant parts, seeds, and propagative material are subject to inspection: non-compliant material may be refused entry or destroyed.
Federal Regulations — APHIS
Under 7 CFR §301.38, USDA-APHIS regulates the movement of rust-susceptible plants and propagative material to prevent the spread of black stem rust.
- Interstate movement of regulated barberry and related shrubs requires certification or a permit.
- APHIS maintains and updates lists of rust-resistant and regulated plant varieties.
- USDA-APHIS Black Stem Rust & Barberry Program — federal guidance, protected area maps, regulated articles lists.
- APHIS Barberry Rust Resistant Cultivar Lists
- Cereal Rust Fact Sheets
