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MSU researchers establish biocontrol plot for testing organic weed control

Working on control methods using pathogens to infect weeds
MSU Thistle-Fusarium Biocontrol Plot.png
Posted at 5:26 PM, Jun 26, 2024

Operated by Daryl and Linda Lassila, Lassila Farms is a fourth-generation farm in Great Falls. They produce a variety of crops like buckwheat, peas, barley, and lentils, while implementing organic farming practices as much as possible and limiting the use of conventional chemical products. Most of their fertilizer is derived from natural ingredients, and they utilize conventional tilling methods as weed control over herbicides.

Daryl switched to utilizing organic methods more than 20 years ago. He says, “The drive was there because I was tired of the chemicals on the other side. I do not like being around them. I do not like the idea of it being in our food chain. I don't like the idea of it being in the soil that we’re supposed to be cherishing."

Daryl and Linda opened their farm to other producers, as well as members of the Montana Farmers Union and the Montana Organic Association, to give a tour of his farm and hold discussions on topics like transitioning cycles, green manure plow downs, and weed control methods.

Plant Pathologists from Montana State University also gave a presentation on their work in creating an organic pesticide. In collaboration with the Organic Advisory and Education Council, MSU researchers are currently working on testing weed control for organic farming by utilizing fusarium oxysporum, a pathogen that can cause disease in plants.

The pathogen is host specific, meaning different strains of the pathogen will affect different species. They established a thistle-fusarium biocontrol plot on Lassila Farms, where they are monitoring a plot where Canada thistle grows. Canada thistle is known to be extremely harmful to crops and pastures, soaking up water and causing soil to dry out. The goal of the project is to use fusarium oxysporum to target and poison Canada Thistle without affecting the nearby crops.

Dipiza Oli, a graduate plant pathology research assistant at Montana State University explains, “Fusarium oxysporum has been used in the past to control other weeds. So, what we are expecting is this is a type that goes only to Canada thistle, because it's very specialized. From last year's data, we found that it does not go to any other crop in the field. So let's see what happens with this one.”

This fusarium-thistle biocontrol plot is being used to monitor only how efficient the pathogen is at infecting the Canada thistle. This is a repeat trial of the same efficiency trial done last year in Highwood, which yielded positive results. More extensive crop safety trials are being conducted in Bozeman on various research farms, where they are monitoring the health and safety of crops like wheat, barley, lentils, and peas after being exposed to the fusarium oxysporum.

It’s still early in the season to collect data, so MSU researchers plan to return to the biocontrol plot on Lassila Farms later in July to assess the differences in the Canada thistle.