Evaluation of the efficacy of GF-120 to potentially replace organophosphate insecticides for control of apple maggots in organic and conventional orchards

Project Code: BPI07-100

Project Lead

Julia Reekie - Agriculture and Agri-Food Canada

Objective

To evaluate the performance of the spinosad-based product GF-120 to establish appropriate label claims, determine the lowest effective application rate, optimize use for maximum apple maggot control, and disseminate findings to industry, the scientific community, and in support of registration of this use

Summary of Results

Background

The apple maggot (Rhagoletis pomonella) is indigenous to North America and has been found in all Canadian provinces with the exception of Newfoundland. There is zero tolerance for fruit infestation by apple maggot in the marketplace, making effective control of this pest of vital economic importance. The loss of older chemistries through re-evaluation has made the search for alternative controls for long term, sustainable management increasingly urgent. The organic market currently has limited access to control products, with nothing that acts to reduce the overall population.

GF-120 NF Naturalyte Fruit Fly Bait (spinosad) is a promising option. Studies have shown that the baited formulation of GF-120 is effective in the control of a number of fruit fly species and a recent study using GF-120 to control apple maggot flies has shown potential.

Approaches

To test efficacy and facilitate potential label expansion of this product, trials were undertaken in Nova Scotia and Ontario in 2007.

In 2008 more trials were conducted to optimize the delivery of this product for suppression of apple maggots in organic orchards. Two different application intervals, perimeter sprays and alternate row spacing were evaluated for their effectiveness. Trials were also carried out to refine application methods within tree canopies, and to prune large-sized trees for better penetration of GF-120 into inner tree canopies.

Results

Results of trials showed that GF-120, when applied every 7-10 days provided adequate apple maggot control in orchards with severe pest pressure and resident infestations. If the apple maggot is not a resident pest, results indicated that it may be possible to apply spray to alternate tree rows or only to the perimeter of the orchard to control a fly-in pest situation. In orchards of very large trees with dense canopies, uniform distribution and good penetration of GF-120 into tree canopies were shown to be extremely important to attain effective apple maggot control.

The results from these trials were used to support an application for an emergency use registration of the product for the suppression of apple maggot in organic apples in Nova Scotia, New Brunswick, Prince Edward Island, Ontario and Saskatchewan in 2008, and subsequently a joint Agriculture and Agri-Food Canada/Ontario Ministry of Agriculture, Food and Rural Affairs submission to the Pest Management Regulatory Agency which resulted in a full registration in Canada for this use pattern.

Conclusions

Results from these studies have also showed that GF-120 is as effective as kaolin clay in protecting apple orchards from apple maggot damage. However, the success of its use lies largely in understanding the orchard situation and GF-120 must be implemented accordingly to achieve efficient and effective results. The successful registration of GF-120 means that the product could play a significant part in an apple pest control strategy, and assist growers in transitioning toward more sustainable insect management strategies.

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