Purple Loosestrife Beetles

Purple Loosestrife is an invasive species that is common on our lakes and wetland areas in Wisconsin. The plant has a very pretty, purple, spiked flower.  The problem with loosestrife is that the root systems are very massive and they tend to crowd out native plant species.

Purple loosestrife started out as a plant that was sold in nurseries. It produces a huge amount of seeds and can be transported by birds and wind.

Control measures include pulling plants, cutting flowers, spraying with glyphosate or imazapyr, and biocontrol.  Pulling purple loosestrife is difficult when the plant is big.  It is hard to get all of the roots.  Spraying is tricky too due to the fact that the plants are usually in or near water. Aquatic use formulas should be used and a permit might be necessary. Cutting the flowers and destroying only stops the spread of seeds and does not get rid of the plant. Biocontrol utilizes Galerucella Beetles.  These beetles eat the loosestrife plant.

The beetles can be raised in pens.  Last year, we received beetles from Burnett County.  They were placed on both Long and Des Moines Lakes. The beetles were effective. I saw evidence of them eating the loosestrife. This year we will be raising our own beetles. In a joint effort with the Long Lake Association and the Des Moines Lake Association and Burnett County a “pen” will be established on Mark and Jill’s property which is on both lakes.  We expect to have the pen up and running in time for the annual meeting on the Saturday of Memorial weekend. So If you come to the meeting you can see the operation. Owners on  both lakes are welcome to come see the pen if interested.

Beetles were collected 5 times for approximately 2500 beetles and cage will be dismantled soon. Other cages/propagation areas fared better than the one on our property for some reason. Releases were on Long Lake, Des Moines Lake, wetland area across from Des Moines lake trail which is/was a hotbed of loosestrife, as well as marshy area of Hanscom lake across Long Lake Road which is heavily rife with it.

A large patch of Purple Loosestrife was recently removed from the low bog area on Arbutus Dr. by volunteers. Mark Michel is a property owner on both lakes and is active in the Long Lake Association. Chris Franken and Holly Huso are Des Moines Lake Association board members. Beth Ihry, Des Moines Lake Association member, also worked to remove the invasive plants. If you, as a property owner on either Des Moines or Long Lake, think that you may have Purple Loosestrife, contact your lake association or reach out to Mark Michel or Chris Franken. Together, we’ll work with other members/volunteers of our associations to identify and remove Purple Loosestrife on both lakes.