Counter-Attacking Loosestrife

By Don Kissinger, Third Quarter 2002

This past winter, spring and summer I started work trying to combat purple loosestrife in and around a few of the communities I work with. Now you may say what is this urban forester doing in wetlands? Well wetlands at some point in time come in contact with uplands, which in most cases have trees, plus the definition of Urban Forestry encompasses all areas within the confines of a community, from tree-lined boulevards, to parking lots and yes, wetlands. As many of you may or may not know purple loosestrife (Lythrum salicaria) is a wetland herb introduced as a garden perennial from Europe during the 1800’s . Admittedly while in bloom it is a neat looking plant, however it is aggressive in displacing native vegetation and degrades wildlife habitat. If left unchecked purple loosestrife can overrun wetlands of almost any size and can severely choke open waterways to the detriment of recreation use.

In the 10+ years I have worked for the DNR in Wausau I’ve become acutely aware of this plant, and in particular a line of loosestrife heading north from just after the on-ramp of Interstate 39/U.S. Highway 51 that I take every day. This area was little more than a small patch half the size of a basketball court, now it stretches for almost two miles in length. In the past I’ve contacted WI-DOT where their response has been this is below low priority. In contacting Brock Woods of the Purple Loosestrife Biological Control Program I was intrigued by the potential for rearing Gallerucella beetles as there are two species that appear to do quite a job, are easy to rear and when released work very quickly. The beetles are leaf and stem feeders reducing both growth and reproduction of purple loosestrife, they are most effective in the larval stage and pretty much host specific, thus as loosestrife presence is reduced so is the presence of beetles. The programs hope is to reduce purple loosestrife so that native species will again be the majority component of the environment. The concerns I had regarded the time commitment, where I would be able to harvest the loosestrife for beetle rearing and finding a secure place to propagate both plants and beetles.

Help came in the form of Marathon County DNR Wildlife Biologist Rich Weide and Village of Rothschild Forester Rex Zemke. Rick was working with other groups north of our area and had done this in the past, he showed both Rex and I the size of plants needed to sustain a propagation population and physically provided us with both the beetles and netting to rear the beetles. Plus all out of pocket costs paid for by the village to propagate the plants were reimbursed through a wildlife management fund administered by Rick that Weyerhauser Corporation has as required by their Federal dam licensing agreement. Although the costs were well under $100 the village would not have entertained the project if the materials were not fully funded.

I approached the village as we had successfully performed projects in the past, they were located near my release sites and they had a fenced in nursery where security would not be an issue. It just so happened that Rothschild has a substantial loosestrife problem on their own Cedar Creek Wetland, which flows into the Wisconsin River near my planned release sites, thus they wanted to propagate beetles for their own use also.

The total amount of time spent by me wasn’t that much, probably 3 ½ full days, that’s why I’m hoping you foresters that have loosestrife on nearby state, county, city or private properties may consider this process. For me it began by contacting the WI-DOT and going through the permit process to release beetles on their property and performing this in a fashion where we did not create an accident or get ourselves killed. I initially contacted them in February of 2002 explaining my thought process and providing maps. I received the permit a few weeks later.

The fun began in mid April, Rex and I donned our chest waders and sloshed around the banks of Cedar Creek where in some cases we chiseled through ice encrusted roots to remove enough plants for about 30 pots. After harvesting the plants, we had to remove any non-purple loosestrife plants from the rootball (a lot of hand work and washing of roots). Next, was mixing the potting soil with peat moss, cutting off the dead stalks, placing the rootballs in the 3-5 gallon plastic pots and finally covering the entire shooting match with netting to allow an exclusive home for the beetles when placed on the plants. The plants were to have a ready source of water at all times, thus it was suggested they be put in childrens’ wading pools. We used old car top carriers and pools that were picked up during the village’s spring clean up, thus no cost. The first couple of weeks the plant growth was near non-existent, we began to question our work, but then they took off.

Maps were made of the release sites in reference to highway signs, mile markers and bridge overpasses. It was a little under a two mile stretch of the highway so it should be easy to see how, or if we will be successful, either way we will definitely perform the project again next year to give it a fighting chance. Evidence has been promising as Rick noted beetle releases from a couple years ago on an island within the Rib River in Wausau has shown no flowering where plants had been prolific in the past. When I told DNR Invasive Plants Specialist Kelly Kearns of my release location she questioned the ability of the beetles to do well within the highway median due to breezes created by the oncoming traffic, only time will tell. Although as crazy as it sounds while depositing the plants, beetles and larvae in the middle of the median it was not breezy at all, due to being lower than the highway and in amongst the tall grasses, cattails and loosestrife.

To wrap this up, I encourage any foresters with this problem in their area to contact Brock Woods at (608) 221-6349 regarding the beetle rearing procedures or me at (715) 359-5793 for all the ins and outs of this particular project. It is a great opportunity to put into practice some of the themes from our past years Forestry Statewide Meeting, where we were asked to better connect, communicate and cooperate with other land users. We received fantastic coverage from both our local newspaper (front page) and both television stations, it also showed our inter-agency cooperation with wildlife along with a municipality, a paper company and the Department of Transportation.