Italian ryegrass has been one of the most troublesome weeds in Mississippi for nearly 20 years. Many populations across the state are resistant to ALS herbicides, glyphosate, and ACCase herbicides such as diclofop and clethodim. Additionally, there have been some
Management As with any successful weed control program, a multi-faceted approach is the most effective and economical strategy for managing Italian ryegrass. Mechanical and preventative control Italian ryegrass seed must be close to the soil surface (<0.5 in) for germination
Italian ryegrass resistant to clethodim is present in Mississippi.
Spring tillage with the intent of controlling GR Italian ryegrass is nearly futile.
Fields to be planted to rice that contain glyphosate-resistant Italian ryegrass should be managed aggressively
An early burndown targeting Italian ryegrass is more critical in fields to be planted to corn than those that will be planted to other crops.
An early burndown application in January or early-February for Italian ryegrass allows time to determine how well the first application worked and flexibility in deciding how to control escapes.
The best chance for reliable glyphosate-resistant Italian ryegrass control is with residual herbicides applied in the fall.
The preplant interval for clethodim application before planting a grass crop (corn, rice, grain sorghum) is real and should be strictly observed.
Barnyardgrass is resistant to five herbicide modes of action in rice.
Italian ryegrass plants germinate from fall through early spring, are highly competitive, and grow rapidly in the winter and early spring months.
The severity of the glyphosate-resistant (GR) Italian ryegrass problem in Mississippi has varied from year to year. This year has been the worst year since the initial confirmation in 2005, and GR Italian ryegrass is spreading.
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