New herbicide registrations for vegetable crops in 2013

Prowl H2O and Dual Magnum labels expanded for green onions, beet greens, cilantro, sweet potatoes and pumpkins.

The Dual Magnum and Prowl H2O labels have been expanded to include several new uses. The Dual Magnum Michigan 24c indemnified label was expanded to include garden beet greens, cilantro, pumpkins and sweet potatoes. To access the label, go to and select Indemnified Labels under the Products tab in the navigation bar at the top. Enter your state and crop, agree to the indemnification statement that you will hold Syngenta Crop Protection harmless for any crop injury for this use, and then you can download the label. Other states may not have the same crops on their 24c labels. There is crop group residue data for all the crops listed on the Michigan 24c label, and these crops may be added to labels in other states.

The Prowl H2O Section 3 label was expanded with a supplemental label for use preemergence on green onions and related crops. Previously, Prowl H2O was labeled for use after the two leaf stage of green onions. The new label allows use after seeding green onions and before emergence. The label allows use of 2 pints (0.95 lb ai) of Prowl H2O preemergence and 2 pints after the two leaf stage. A maximum of 4 pints (1.9 lb ai) may be applied per crop. It should not be used on soils with less than 3 percent organic matter. There is a 30-day preharvest interval (PHI). Other crops in the green onion subgroup included on the new label are chives, leeks, scallions, green shallots and Japanese bunching onions. Prowl H2O is the only preemergence herbicide labeled for use on green onions on muck soil.

A new formulation of napropamide (Devrinol DF-XT 50 DF) is now available. The formulation is UV protected, so it is less sensitive to solar degradation and lasts about twice as long in the soil as the original formulation. Devrinol DF-XT should provide four to six weeks of weed control under normal conditions. Devrinol is a good preemergence herbicide for control of annual grasses and some broadleaves early in the growing season. It is safe on vegetable transplants and does not stunt growth when soil temperature is below 50 degrees Fahrenheit. Devrinol also is a good early-season herbicide on strawberries.

Spin-Aid (phenmedipham) is now marketed by Engage Agro. It is a post-emergence herbicide for red beets and spinach. It controls several broadleaves including wild mustards, common lambsquarters, ground cherry, common chickweed, common purslane, common ragweed and sow thistle. Spin-Aid can injure beets and spinach, so follow label instructions carefully. It is a restricted use pesticide (RUP) and a pesticide applicator’s license is required for purchase.

To obtain labels for most pesticide and herbicide uses, go to, and type in the name of the pesticide. Recommendations for weed control in Michigan vegetable crops can be found in the Michigan State University Extension bulletin E-433, “Weed control guide for vegetable crops.”

Dr. Zandstra’s work is funded in part by MSU‘s AgBioResearch.

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