Featured Pest: Italian Ryegrass
With developing resistance, new disease races and the spread of damaging insects, retailers and growers alike must be increasingly aware of harmful pests and how to prevent or treat them. In each issue, Syngenta will track and tackle your biggest “Pest Pet Peeve." In this issue, the featured pest is Italian ryegrass.
Italian ryegrass (Lolium multiflorum) is an open-pollinated, upright annual grass weed that has become glyphosate, ACCase-inhibitor and ALS-inhibitor herbicide-resistant. While Italian ryegrass was once primarily a problem specific to the Mississippi Delta in the winter, it has now become an unwanted visitor from coast to coast. The International Survey of Herbicide Resistant Weeds concludes this grass weed is currently resistant to four herbicide modes of action in 10 states.
Italian ryegrass grows vigorously in mild winter temperatures and fertile soils. While peak emergence begins in the fall, Italian ryegrass continues to grow throughout the winter and presents another flush in early spring. The similar growth habit of cereal crops and Italian ryegrass contributes to its aggressive and competitive nature, resulting in significant yield reduction in wheat. Italian ryegrass also grows rapidly and can produce up to 45,000 seed from just a single plant.
Wheat growers in the Pacific Northwest know firsthand how threatening Italian ryegrass can be to their valued cereals investments. Not only is it reducing yield, Italian ryegrass is also resistant to some herbicides commonly used to control weeds in wheat. This weed is an undeniably major concern for Pacific Northwest wheat growers, and they are not alone.
Halfway across the country, Italian ryegrass is also causing problems. “In studies we’ve conducted, Italian ryegrass can reduce wheat yields by up to 70 percent, so identifying and controlling the weed before it can cause that yield damage is very important," said Dr. Dick Oliver, weed scientist for the Division of Agriculture, University of Arkansas.
Without proper management solutions, Italian ryegrass will continue to threaten wheat production. Syngenta can solve the complexity of managing Italian ryegrass by providing preventive solutions to keep the rampant grass weed from choking out the valuable wheat crop. For example, Oliver and others in the South are finding an initial burndown application of Gramoxone Inteon® herbicide can help reduce Italian ryegrass populations. Scouting should continue throughout the early stages of planting wheat, and a follow-up postemergence herbicide should be applied if Italian ryegrass is present. Mode of action ro