Weed control continues to be a challenge for producers of pesticide-free horticultural crops. Many pesticide-free methods are costly and/or labor intensive. This project is funded by the Environmental Protection Agency Region 5/American Farmland Trust grant. The research project facilitates the development of pesticide-free agriculture production methods and may help farmers transition from soil fumigants to reduced-risk pest management strategies. Specifically, this project aims to further the research into canola as a cover crop for pre-emergence weed/disease suppression. The study will determine the effectiveness of several pesticide-free methods of killing canola to maximize weed-suppression in the production of strawberries, pumpkins, and fresh-market new potatoes, three high-value crops in the Midwest.
The three different treatments of pesticide-free methods include burning with a propane torch, spraying with certified organic Natural Horticulture Vinegar: 20% acidity and a roller/crimper.
The roller/crimper is a ground-driven tractor attachment that can be mounted on the front or rear of the tractor. You can push or pull the roller/crimper at cover crop flowering to roll down fall-seeded cover crops such as rye or canola. This creates a bio-suppressive cover crop mat up to five inches thick. This mat then shades out weeds, preventing germination and thus reducing weed populations.
Propane Torch Burner
The propane tank is fastened to a backpack and has a torch attachment.
Certified Organic Natural Horticulture Vinegar: 20% acidity
A backpack sprayer is used to apply the certified organic Natural Horticulture Vinegar: 20% acidity.
Toxin Released by Dying Root Tissue of Canola
Canola is used as a cover crop because of the mat that is created when killed, which shades out weeds. However, canola also releases a toxin from its root tissue as it is dying that prevents weed seed germination. The toxin contains several chemicals including allyl isothiocyanates (AITC) (Pritts). Allyl isothiocyanates (AITC) are derived from the breakdown of sinigrin a glucosinolate (Higdon, 2005) The AITC is toxic to the plants that produce it, which requires it to be stored as a larger molecule called a glucosinolate. In this form, the AITC is inactive. If tissue of canola chewed by an attacker, such as a caterpillar the enzyme called amyrosinase is released that breaks down the glucosinolate and releases AITC to drive the attacker away (George, 2003).
George, H. (2003) What Is Isothiocyanate?. Retrieved from
Higdon, J.(2005) Isothiocyanates. Retrieved from
Pritts, M., Nonnecke, G. Preplant Cover Crops for Strawberries. Retrieved from