Parterning with MSU on a Biocontrol for Thistle
While we normally aren’t focused on killing at Organic Lawn, thistle is the WORST! Canada thistle is a perennial noxious weed that is the bane of Montana organic food and lawn growers. We recommend a holistic approach, focusing on growing thicker turf to outcompete thistle by mowing and watering properly only using organic fertilizer programs that encourage healthy soil life, build more top soil, and increase soil organic matter (aka soil carbon); and weed-wacking or pulling thistle patches adjacent to the lawn well before they can go to seed. That said, Canada thistle has an extensive rhizomatous root system and can produce up to 5,000 seeds per stem, which makes keeping them at bay tricky. Because it is such a noxious nuisance, we’ve been searching for more natural and effective tools to control it.
In the Fall of 2021, we partnered with researchers at Montana State University – Dr. Tim Seipel, Dr. Jed Eberly, Melissa Maggio, Elizabeth Hecker, Dr. Patrick Carr, and Dan Chichinsky – to work on determining whether naturally occuring thistle antagonist, Puccinia punctiformis, can beat back our prickly foe. Puccinia punctiformis, aka Thistle Rust, is a fungal pathogen that has potential to be an effective Canada thistle biocontrol agent. The pathogen lives as a parasite in the thistle’s extensive root system. Once infected, individual thistle plants slowly develop pustules and tissue necrosis.
Thistle Rust is applied to a healthy thistle plant in an Organic Lawn yard. Hopefully the naturally occuring fungal pathogen will stress and eventually kill the noxious weed - all without herbicides!
Like all good things in life, this can take a while, sometimes up to one or two years after inoculation. That said, we are excited to partner with MSU to help try to bring this natural thistle control option to Bozeman lawn owners. We all know that spraying herbicides is not only a terrible idea for you, your family, and your pet’s health, but it doesn’t work. If it did work, we wouldn’t have so much thistle in Bozeman. The chemical lawn care companies have been spraying poison willy nilly all over town for decades to no avail and we are excited to work with new tools and fresher minds through this initiative!
If you have any questions, give us a call. We would be happy to talk to you about it.