Whitehall Biological Weed Control Project: Why Do We Have an Insectary "Weed Garden?"

The insectary maintained by the Whitehall Biological Weed Control Project at Whitehall High School is a noxious weed garden with several purposes and an interesting history. As of this writing, we are "lovingly" growing the state-designated noxious weeds spotted knapweed, Russian knapweed, yellow toadflax, and whitetop.

We also have one or more insect/mite species that help control each of these nasty weeds, established in the insectary. So, we are carefully cultivating the weeds to attract insects/mites to kill the weeds... An interesting concept.

One of the long-term functions of the insectary is noxious weed control education. It is a place where noxious weed species are planted, and insect and mite biological control agents (bioagents) are also established. Therefore, we can show these specimens to people so they can then recognize them in the field. Knowing what these weeds and critters look like allows folks to better manage their own land, help their neighbors with weed management, and correctly report the presence of weeds or biological agents to county, state, and federal land managers. Student groups also often tour the insectary to learn about weed control and plants/insects/mites in general. The insectary provides samples for us to take to the many presentations and workshops we host for groups in the area, such as garden clubs, weed managers, and civic organizations.

A second function of the insectary is to "mass rear" the bioagents for release in the field. When we have a newly approved bioagent, we can carefully grow it in the insectary and collect it for controlled release. Bioagents newly released in the field often disperse widely and are hard to find/collect for several years until their numbers build up. The insectary allows us to produce releases more rapidly than from field release sites. That is why it is called mass rearing.

The Whitehall insectary has a long history. I started it in 1993, modeled after Jim Story's insectary at the Western Agricultural Research Station near Corvallis, Montana.

We transplanted spotted knapweed plants into insect corrals "fenced" with metal flashing (to hold the knapweed root-boring weevils within, as they do not fly), and into 6x6x12' net insect cages (to hold the knapweed root-boring moths that do fly). We mass-reared the moth for over a decade until it became established virtually everywhere in Montana. They disperse widely by flying. Because they are well-established, we no longer mass-rear or collect them. We continue to produce root-boring weevils in small numbers at the insectary, although we collect most of our releases from well-established field sites around the state. In the late '90s, we greatly expanded the spotted knapweed insectary for mass rearing. Every year we had to transplant more of the weed in as the insects rapidly kill the plants. The Whitehall Project crews and WHS students collected the weevils from the insectary for release in the field.

In the 2000s, we added the noxious weeds Russian knapweed, yellow toadflax, and whitetop to the insectary. For Russian knapweed, we grow a stem-galling wasp and a tip-galling midge. The yellow toadflax is used to grow a stem mining weevil and a stem galling weevil. On whitetop, we are just starting to produce a flower-galling mite and hope to have it available for release next year.

This season we are redoing much of the insectary and producing interpretive signs to help folks understand what they are seeing. As you exercise around the WHS track, feel free to tour the insectary on the northwest side. Be mindful not to interfere with PE classes, sports practices, or events. You can also see the insectary from the I-90 east-bound on-ramp. We should have the interpretive signs up by mid-August. Feel free to walk around among the carefully manicured rows of noxious weeds and get to know what they look like. If you have questions or would like a release of spotted knapweed root-boring weevils (the only species we are still collecting this season), please call project coordinator Todd Breitenfeldt (406-498-5236) or AmeriCorps/MCC volunteers Bridget Danielson (218-820-6246) or Eleni Voulgaris (562-292-2575) during normal business hours. Have fun whacking those weeds!