Common Ragweed and Burndown Programs Peanut Notes No. 42 2018

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Some fields, especially those in conservation tillage, can have emerged summer weeds to contend with. Common ragweed can be one of those weeds. With some of our weather patterns, tillage and bedding practices and planting are not aligned very well. Although auxin products were helpful much earlier in the spring, glyphosate and paraquat are the key burndown products at this point. Recently I was asked about the possibility of using Strongarm to control emerged ragweed. Historically, Strongarm performed well on this weed when applied to the soil at planting or even after emergence. The challenge now is ALS-resistant common ragweed which can be found in a significant number of fields in North Carolina. Some of these populations are also resistant to glyphosate. A burndown rate of paraquat is the best option in many fields (prior to peanut emergence) because we often do not know if the population is resistant to ALS-inhibiting chemistry. Our challenge during the next week or so is that some fields are planted and not sprayed with burndown herbicides or residual herbicides. Each field needs to be discussed individually to come up with the best approach to controlling weeds.