Tag: Arrest the Pest

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Invasive weeds found in Winona County

Invasive weeds make yet another first appearance in southeast Minnesota. The Minnesota Department of Agriculture (MDA) has positively identified the invasive weed Palmer amaranth in Winona County.

Invasive Weeds
It’s official. Palmer Amaranth has made its first appearance in Winona County down in southeast Minnesota. (Photo from MDA.org)

The MDA was contacted by crop consultants after they discovered several suspect plants in a soybean field. MDA staff scouted the area and removed 20 Palmer amaranth plants, which were then confirmed as Palmer by genetic testing. The field has since been treated with a herbicide application, and follow-up scouting by the MDA did not find any new invasive weeds. The site will be monitored for three years for any new Palmer amaranth.

The MDA is trying to determine the source of the invasive weed.

Now is the time when Palmer amaranth becomes visible in agricultural fields. The MDA is asking farmers, crop consultants, and agronomists to report any suspicious plants to the Minnesota Department of Agriculture’s Arrest the Pest line at 1-888-545-6684 or arrest.the.pest@state.mn.us.

If you’re one of the fortunate ones who haven’t seen Palmer Amaranth show up in your fields, here’s a quick refresher on identifying the plant, courtesy of Purdue University.

Since it was first discovered in the state in 2016, Palmer amaranth has been found in nine Minnesota counties, including Winona County. Details of previous finds can be found on the MDA website.

Palmer amaranth is listed as a noxious weed in Minnesota. All above and below ground parts of the plant must be destroyed, and it cannot be moved. The weed is also listed as a prohibited weed seed in the state. This means no Palmer amaranth is allowed in any seed offered for sale in Minnesota.

Left uncontrolled, a single female Palmer amaranth plant typically produces 100,000-500,000 seeds. It is resistant to multiple herbicides, can cause substantial yield losses, and greatly increase weed management costs in soybeans and corn.

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Japanese Hops are MDA Weed of the Month

When you hear the word “hops,” you might think of beer. Hops are used in beer production to add bitter, floral, fruity, or citric flavors and essential oils for preservation. However, Japanese hops lack an essential resin for beer production. Common hops are a similar native species and can be used for beer production. Introduced to North America as ornamental vines, they are native to eastern Asia. Unfortunately, Japanese hops escaped cultivation and have become invasive.

Japanese Hops
Japanese hops form a dense mat and can choke out other plants. (Contributed Photo)

Japanese hops have distinct bracts where the leaf and petiole attach to the stem. The leaves have toothed edges with 5 to 9 lobes arranged palmately (shaped like a hand with fingers extended), while common hops only have up to 5 lobes.

The weed has both male and female vines. With female vines, seeds are produced in conical husks; male vines produce pollen from flowers. Hooked hairs on the stem and leaves help the vines climb but can irritate human skin after contact.

Seeds from the vine are easily dispersed by wind, water, wildlife, vehicles, and equipment. This allows the invasive weed to grow very rapidly. In just one season, they can grow up to 35 feet long. The vines twine around to climb vegetation and structures, capable of smothering desirable vegetation and producing dense mats several feet thick.

Japanese hops have distinct bracts where the leaf and petiole attach to the stem. (Contributed Photo)

Japanese hops are annual vines in Minnesota but can be perennial in warmer climates. They thrive in partial to full sun including next to rivers, along roadsides, grasslands, and forest edges.

They’ve been found in southeastern Minnesota along the Root and Mississippi rivers, as well as in the city of Winona. Most infestations are on riverbanks and creep into adjacent forest understory.

If you suspect you have found Japanese hops, please take pictures of the plant, note the exact location, and send a report to arrest.the.pest@state.mn.us. If you have questions or would like more information, please visit the Minnesota Department of Agriculture or the Midwest Invasive Plant Network websites.