Have you noticed an orange or rusty look on the grasses in your pastures? It’s not grass changing colors for the fall. It’s actually a fungal pathogen called “Puccinia,” also known as “rust.” It’s found in all temperate zones of the world, and comes in a variety of species that can infect all kinds of plants, from fruit crops to malting barley. It may look harmless, but it can reduce forage palatability and nutrient value, make plants more susceptible to rot, and reduce the productivity of cereal grains. For example, stem rust destroyed more than 20% of U. S. wheat crops several times between 1917 and 1935. The last U. S. outbreak, in 1962, destroyed 5.2% of the crop.
It’s hard to quantify the effect of Puccinia on forages. It might impact a small part of a pasture or acres and acres. It travels in the wind, on animals and equipment, and in rain splashing from an infected plant, so it’s pretty hard to avoid entirely.
One solution to the rust problem has been to try to develop plants that are resistant to Puccinia. So far, the best that breeders have been able to do is to create grass cultivars capable of fending off Puccinia for up to five years. Another solution is to identify the type of Puccinia in your region and choose grasses that are not affected by that specific strain. Perennial ryegrass is especially affected, although it’s not clear which specific rust is the culprit. If you see rust in your pastures, you may want to avoid grazing to give the plants time to recover. The rust eventually goes away, but may destroy its host forage plants in the process.
To solve the problem of Puccinia, researchers are gathering information about the genetic makeup of different infections, and they need your help. Dr. Kirk Broder’s phytopathology lab is looking for rust samples in pastures in Pennsylvania, New Hampshire, Maine, and Vermont. If you see Puccinia in your pasture, please send a sample to Dr. Broder. The lab will extract DNA for genetic analysis to create a knowledge base that will help scientists get to the bottom of this. The more samples they get, the better we’ll all be.
Here’s what to do:
Collect a few blades or leaves with signs of Puccinia (rust), and put your sample in a paper envelope. Include information about the location (address or GPS coordinates) of where you found it, and the name of the grass, if you know it.
Send your samples to:
384 Rudman Hall
University of New Hampshire
Durham, NH 03824
Now you’re a hero in New Hampshire and On Pastures everywhere!