OSC Activity F.2

Weeds are the predominant yield inhibitor in lowbush blueberry fields.  Conventional weed management practices rely almost exclusively on herbicide applications for weed control.  The perennial nature and growth habit of the crop make it difficult to apply many organic weed management techniques adopted by other horticultural industries.  The inability to manage weeds organically in lowbush fields is the main issue limiting the expansion of the industry.  Consequently, the overall objective of this research is to develop viable weed management options for organic lowbush blueberry fields. 

Specific objectives include:

1. Measure the impact of field sanitation and pH manipulation on weed growth, development, and reproduction and blueberry growth and development.
2. Measure the impact of field sanitation on weed seed viability
3. Measure the impact of pH manipulation on soil activity and mycorrhizal populations
4. Determine timing of weed clipping that optimizes blueberry yields and reduces fitness of perennial species

The wild blueberry (Vaccinium spp.) is the most important fruit crop of Quebec and the four Atlantic provinces.  Commercial fields are developed from native stands on deforested or abandoned farmland by removing competing vegetation.  The management of indigenous stands allow for the marketing of a ‘wild’ agri-food commodity.  The fields are predominately managed on two-year cycles with the perennial shoots pruned in alternative years to maximize floral bud initiation, fruit set, yield, and ease of mechanical harvest.  In conventional systems, selective herbicides and low levels of N, P, and K fertilizers are applied to control competing weeds and encourage berry production.  Due to the perennial nature of the wild blueberry, common horticultural techniques such as crop rotation and cultivation are not viable management options.

Weeds are the major yield-limiting factor in wild blueberry fields.  Poor weed control will reduce yields, hinder blueberry clonal expansion, and may lead to enhanced disease incidence.  Adoption of organic production of lowbush blueberries is predominately limited by the inability to control competing vegetation.  Growers typically are unable to maintain profitable organic production due to the growth and spread of perennial weeds.  As a result, very little blueberry land in Eastern Canada is managed organically despite repeated efforts and strong interest.  The focus of the proposed research will be the development of organic weed management techniques that are economically viable and easily adopted by growers in the region.  Trials will be conducted to evaluate field sanitation, soil pH manipulation, and canopy management techniques.  Research will occur on commercial farms where possible and data collection will include an analysis of input costs to determine profitability of the various management options.  The ultimate goal is to integrate the information gained into an effective weed management program for organic wild blueberries.  The development of feasible weed management systems for wild blueberries will assist current growers and should lead to growth in the industry.

• Berries, Berries, Berries [PDF - 5.9 MB]
  • The Canadian Organic Grower. 2012
• Weed Control in Lowbush Blueberries [PDF - 92 kB]
  • The Canadian Organic Grower. 2012
    

• Challenges and opportunities for integrated weed management
  • Weed Science (2002) 50: 273-280
• Economic analysis of organic pest management strategies for lowbush blueberries using enterprise budgeting [PDF - 1.4 MB]
  • Maine Agricultural and Forest Experiment Station, University of Maine. 2008
• Impact of blueberry harvesters on weed seed dispersal within and between fields
  • Weed Science (2009) 57: 541-546

• Agriculture and Agri-Food Canada