Steps to starting a beetle rearing project
There are many readily available protocols online for rearing Galerucella beetles for release, and the rearing and release of purple loosestrife biocontrol agents can be an interesting and useful project. A small initial investment in time is required to get the appropriate permission for collection of the beetles and the purple loosestrife, for the release of the beetles, and in acquiring some common gardening supplies. This investment can result in a potentially large payback in control of an invasive plant species.
We decided that instead of re-inventing the wheel, we’d follow protocols already developed for beetle rearing. They include the following:
- Biological Control of Purple Loosestrife: A Guide for Rearing Leaf-Feeding Beetles, University of Minnesota Extension
- Homegrown Beetles: Backyard Biocontrol, University of Connecticut Integrated Pest Management
The basic steps of a beetle rearing project, which will be covered in more detail in future blog posts, are the following:
- Obtain permission from the appropriate authorities (for West Virginia, the West Virginia Department of Agriculture) to move, grow and re-introduce purple loosestrife to the field. It can be illegal to move or release invasive species, so having the appropriate permit is important.
- Obtain permission to release the beetles in appropriate sites: sites with a large enough infestation of purple loosestrife to support beetles, that are unlikely to be subject to annual spraying
- Obtain supplies for raising your beetles: 3-5 gallon pots, potting soil, fertilizer, children’s swimming pools (I could fit 12 plants per pool), no-see-um netting, tomato cages or other support structures, strong tape, rubber bands.
A beetle rearing setup.
- Dig up the purple loosestrife root crowns by the beginning of April; pot them in moistened potting soil and set them in the pools with a few inches of water in each pool. Leave one bare plant per pool, to attract any beetles that might accidentally escape. Make sure the plants are in a nice sunny location.
- Sew the no-see-um netting into sleeve cages to fit around the pots, tall enough to cover the whole purple loosestrife plant (at least 3 feet tall, if not taller). Erect the tomato cages over the plants, then fasten the sleeves over, taping or rubber banding the bottoms of the sleeves (we had to do both), and tying the tops.
- Obtain your beetles, preferably toward the end of May or beginning of June at the latest. They can be purchased, or collected from the field at a previous release site (make sure you have appropriate permission to transport the beetles as well). I was lucky enough to be taken out with West Virginia Dept. of Agriculture staff to help them collect beetles for their own release as well as mine. Introduce the beetles to the plants, and let them start munching away.
- Once the beetles complete their life cycle and you begin to see new beetles (late July or early August), bring the pots to the release sites, take off the sleeves, and allow the new beetles to get used to their new homes!
A Galerucella larva
We will be covering these steps we’ve taken or will take in future blog posts, so stay tuned! It is the hope of our program that the permitted work done this year on the release of purple loosestrife biocontrol agents will build upon our previous and future invasive species management work, enhancing our efforts in West Virginia, and we are looking forward to seeing how the beetles establish in our area!