Rust diseases cut into North Carolina wheat yields

(Southeast Farm Press) – Stripe rust is rare in the Carolinas and Virginia, but this year hot spots of the disease created sporadic problems for growers in the region and contributed to a nearly 10 bushel per acre yield drop in North Carolina, says USDA Plant Pathologist Christina Cowger.

“The last time we’ve seen stripe rust in wheat at damaging levels was 2005. This year growers began seeing yellow, rust-infected patches of wheat, called ‘hot spots.’ These hot spots were scattered throughout the coastal plain of North Carolina,” she says.

Oat crown rust is another disease that rarely occurs in North Carolina. This year it was abundant and is typical of unusual or rarely seen rust diseases on a wide range of wheat and grass crops in the state, according to Cowger.

Leaf rust is the primary rust disease found in wheat in the Carolinas and Virginia, and it occurs to some degree in most cropping seasons. This past season, the disease was much more widespread than usual and caused significant damage to the wheat crop in the region.

It forms reddish pustules or red dots on the leaves of wheat. It’s a fungus that needs living tissue to survive, so it’s happy when the wheat is rapidly growing, and it causes the most problem while wheat plants are still green, Cowger says.

Warm winter and spring temperatures were the main culprits for the increased rust pressure in wheat, but the size of the crop also provided more opportunities for disease to form.

In North Carolina wheat producers harvested more than 770,000 acres. Though average yield was down by 10 bushels from the 2011 record of 68 bushels per acre, total wheat production set an all-time state record of 44.7 million bushels.