Christina Cowger small grains pathologist at North Carolina State University says high relative humidity and moderate temperatures are conducive to scab

Christina Cowger, small grains pathologist at North Carolina State University, says high relative humidity and moderate temperatures are conducive to scab.

North Carolina wheat growers get tips on diseases, weed control

High relative humidity and moderate temperatures are conducive to scab. Wheat that is flowering is susceptible to the fungus.  

High humidity and moderate temperatures are conducive to wheat scab. Wheat that is flowering is susceptible to the fungus. Apply fungicide when the yellow anthers are coming out of the plant, says Christina Cowger, small grains pathologist at North Carolina State University.

“Eighteen to 25 days after flowering is when you can see the symptoms of scab,” she said.

Because of scab risk in North Carolina, Paul Murphy, small grains breeder at N.C. State, said farmers need to look to varieties that offer moderate resistance to the disease.

“To me as a wheat breeder, the disease that scares me the most is scab,” Murphy said. “We don’t have a large number of varieties that are resistant to scab. Pay particular attention when you’re choosing varieties to scab resistance. There is no variety that is completely resistant to scab. The highest level is being moderately resistant.”

As for weeds in wheat, Italian ryegrass is the most troublesome and most difficult to control, according to Wes Everman, N.C. State Extension weed specialist. He said it has become the “driver weed” for most wheat acres in the state

N.C. State is conducting research at Forbis Farms to evaluate early season herbicides to help manage Italian ryegrass that is resistant ALS resistant herbicides. Products were applied pre-emergent and early post-emergent (two-leaf stage).  Scientists are looking at the herbicides Tricor, Fierce and Zidua in the research. No additional herbicides were applied to the treatments for the remainder of the growing season.

As far as yields go, Everman said farmers need to get ryegrass early.

“We had a study last year and we are repeating it this year where we put out a residual early on and got that control in the fall and then compared it to a post plus residual put on in January and February in typical time,” he explained. “We saw about a 25 bushel yield reduction in waiting and only spraying that post later in the season. So you need to get ryegrass early or you can see some major yield reductions from that competition.”

TAGS: Management
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