Organic Agriculture Centre of Canada

Faculty of Agriculture

OSC Activity F.4

Innovative herbicide and fungicide replacement strategies for organic apple production

Activity Researchers

Name Affiliation
Julia Reekie, Lead Researcher
julia.reekie@agr.gc.ca

Research Biologist
Agriculture and Agri-Food Canada
Atlantic Food and Horticulture Research Centre
32 Main St.
Kentville, NS B4N 1J5

Gordon Braun, Co-applicant

Research Scientist
Agriculture and Agri-Food Canada
Atlantic Food and Horticulture Research Centre
32 Main St.
Kentville, NS B4N 1J5
Doug Nichols, Collaborator
 Nova Scotia Fruit Growers' Association
32 Main St.
Kentville, NS B4N 1J5
Eric Specht, Collaborator

 Agriculture and Agri-Food Canada
Atlantic Food and Horticulture Research Centre
32 Main St.
Kentville, NS B4N 1J5
Eric Bevis, Collaborator

 Agriculture and Agri-Food Canada
Atlantic Food and Horticulture Research Centre
32 Main St.
Kentville, NS B4N 1J5

Objectives

Short term objectives:

  1. Develop orchard floor management practices for HoneycrispTM apple to improve tree health, increase productivity, and control pests without the input of chemical herbicides.
  2. Reduce fungicide usage for apple scab control from 8-14 foliar applied sulfur sprays per season to1 or 2 trunk injection applications of non-toxic plant resistance inducers or elicitors.

Long term objectives:

The long term objective of this project is to provide organic apple growers with weed control technologies and a scab management strategy that will increase their profitability and sustainability while dramatically reducing the pesticide load on the environment, reducing carbon emissions  improving soil, water and air quality.

Activity Summary

There is an increasing public desire to reduce potentially harmful inputs which may adversely impact the environment and human health; the use of pesticides in agriculture is one of the often cited culprits. While great strides have been made through integrated pest management (IPM) to reduce insecticide usage in apple orchards there has not been an equivalent reduction in herbicides and fungicides (Prokopy 1991). Considerable research has been invested in herbicide and fungicide reduction, but it is obvious that to make a quantum reduction in herbicide and fungicide use, a revolutionary approach is required. In addition, it must be recognized that major changes in any one part of the apple production system will significantly affect other areas of the production system and thus a comprehensive research approach is required.

In apple orchards, weeds can be a stubborn problem and are usually controlled by applications of herbicides. If left unattended, weeds compete with trees for available resources such as space, nutrients and moisture. Weeds in an establishing orchard can out-compete young trees, leading to a cumulative decrease in tree vigor. Biopesticides can be used to control weeds under organic regimes, but few are available and they are expensive. Flaming can eradicate weeds but it consumes fuel and generates greenhouse gas. Orchard floor management has the potential to replace agrochemicals in weed control and its implementation can minimize the introduction of pollutants to the environment. However, orchard floor management can vary substantially in response to local environmental conditions; knowledge specific to the Atlantic region in Canada on orchard floor management for weed control in establishing organic orchards is limited. Research on long term, non-chemical and sustainable solutions are needed.

The major impediment to organic apple production in most regions of Canada is apple scab, a fungal disease caused by Venturia inaequalis that can result in a complete crop loss (MacHardy 1996). Conventional and IPM growers apply 8 to 10 synthetic fungicide applications annually while organic growers relying upon copper and sulphur often making 14 applications per season (~300 kg sulphur/ha). This represents an un-natural load of synthetic fungicides or copper and sulphur on the environment in addition to large fuel consumption and greenhouse gas generation from their application. Fungicide and copper toxicity to non-target organisms and human sensitivity to sulphur add to the untenable use of conventional fungicides or copper and sulphur within any sustainable production philosophy. Currently, few effective biological alternatives are available and they are typically still applied many times throughout the season. This proposal details a revolutionary approach to managing apple scab and other apple diseases with trunk injections of natural plant or micro-organism substances that induce disease resistance mechanisms in apple trees. Induced resistance to apple scab through foliar applications of natural inducers has already been demonstrated. Trunk injections will reduce the volume of inducer required, target only the crop tree and give long term control with slow release formulations. This will drastically reduce pesticide load on the environment, fossil fuel use, greenhouse gas production and make an economically viable organic apple production system a reality.

Our team aims to develop organic pest management techniques in apple production that will reduce input costs, protect the environment and ensure human health by reducing the use of pesticides. We seek to provide all apple growers with access to new management techniques and information for organic tree fruit production through sound scientific research.

Results

Background and Supporting Documents

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