Biology and Management of Italian Ryegrass |
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CONTENTS |
Italian Ryegrass is a highly competitive winter annual. It has become a serious pest in many peppermint fields West of the Cascade Mountains. Erect stems often purplish at base and 1 to 2 1/2 feet tall. Shiny, dark green leaves have prominent veins. Long spikes have spikelets that are alternate along the stem. Impact on Yield: Its highly competitive nature, coupled with its propensity to develop resistance to herbicides, makes Italian ryegrass a particlularly troublesome weed in mint. Peppermint oil yields have been reduced by as much at 50 lbs per acre. Even after a 73% reduction in the Italian ryegrass infestation, the yield was reduced 23 lbs per acre (Ian Heap). Herbicide Control Notes:
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