Thermal Weed Control for Organic Production

Written by Rosaria Campbell for the Organic Agriculture Centre of Canada (Click here for full reference)

What is Thermal Weed Control?

Thermal weed control is a foliar contact technique in which temperatures of approximately 100 C are applied for a duration of approximately 0.1 seconds, causing intracellular water expansion and cell membrane rupture. This causes the plant to desiccate, with plant death normally occurring within 2 - 3 days. It is not necessary to scorch the weeds. If an imprint forms when the weed is pressed this indicates that the weed was heated sufficiently for cell rupture.

Thermal techniques can be used for top killing in crops such as potato, but the propane consumption for thermal top killing is quite high (70 - 110 kg/ha). The method has also been used in the control of the Colorado potato beetle. However, the level of control is variable, depending on the degree of protection given to the insect by the plant leaves, insect position on the leaf relative to the position of the flame, and the tendency of the insects to drop from the plant in response to disturbance.

• What Type of Equipment is Used?
  
  
• Does Thermal Weeding Damage the Crop?
  
  
• How Effective is Thermal Weed Control?
  
  
• What are the Benefits and Costs of Thermal Weed Control?
  
  
• Weed Sensitivity to Thermal Treatment

Related Links:

The following links provide further information on other research in this area, and on the practical applications of thermal weed control.

Flame Weeding by Fred Cox, Farmer and Independent Consultant, Minnesota. Written for the Sustainable Farming Association of Minnesota. Sponsored by the Agricultural Utilization Research Institute.

Physical Weed Control for Ecological Farming by N.M. Rifai, Department of Engineering, Nova Scotia Agricultural College, Truro, NS.

Flame Weeding on Organic Vegetable Farms by N.M.Rifai, Department of Engineering, Nova Scotia Agricultural College, Truro, NS.

Weed Control for Organic Vegetable Farming in Nova Scotia
N.M. Rifai, Department of Engineering, Nova Scotia Agricultural College, Truro, NS.

References:

1. Campbell, R., N.M. Rifai and R. C. Martin. 2003 (In Process). The potential for thermal and pneumatic weed and insect control in organic production. Canadian Biosystems Engineering. Submitted for review April, 2003.

2. Duchesne, R.M., C. Lague, M. Khelifi and J. Gill. 2001. Thermal control of Colorado potato beetle. In Physical Control Methods in Plant Protection/La Lutte Physique en Phytoprotection, eds. C. Vincent, B. Panneton and F. Fleurat-Lessard, 61-73. New York: Springer-Verlag.

3. Leroux, G.D., J. Douheret and M. Lanouette. 2001. Flame weeding in corn. In Physical Control Methods in Plant Protection/La Lutte Physique en Phytoprotection, eds. C. Vincent, B. Panneton and F. Fleurat-Lessard, 47-60. New York: Springer-Verlag.

For more information please call the Organic Agriculture Centre of Canada at 902-893-7256 or email oacc@nsac.ca