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Title: Weed control without herbicides

item Boydston, Rick

Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/5/2009
Publication Date: 8/10/2009
Citation: Boydston, R.A. 2009. Weed control without herbicides. Potato Association of America Abstracts. #3. Fredericton, NB, Canada. 2009.

Interpretive Summary:

Technical Abstract: Managing weeds without herbicides is challenging and requires an integration of tactics and a change in how weeds problems are approached. Weeds should be managed in a holistic, intentional and proactive manner. Growers that successfully manage weeds in organic systems examine why certain weed species exist in their cropping system and manage the system to discourage weeds. Growers have long used cultural practices and cultivation to help manage weeds in potato production. A well-planned diverse crop rotation and use of cover crops can minimize ‘windows of opportunity’ for weeds to germinate and establish. Cover crops and decaying cover crop residues can smother and inhibit weeds, but if managed poorly, can become a source of weed problems. Manures can be a source of weeds and should be composted to reduce the number of viable weed seeds. Multiple cultivations effectively control early season weeds in potato. Cultivation must be timely and is most effective on weeds in the ‘white thread’ stage to cotyledon stage. Shallow cultivation prevents bringing up new seeds from deeper depths. Managing irrigation before and after cultivation can improve weed kill. Once emerged, potatoes are fast growing and most varieties produce a competitive canopy with weeds. Flaming, acetic acid, organic herbicides have been utilized to suppress small weeds and are generally most effective on annual broadleaf weeds. Perennial weeds, such as Canada thistle, field bindweed, quackgrass, and yellow nutsedge are difficult to manage in potatoes without herbicides. Tillage and summer fallow can suppress difficult to control perennial weeds. New technologies for precision cultivation, flaming, and application of nonselective herbicides are being developed.