Evaluating the Effectiveness of
GF-120 against Apple Maggot in
Apple Orchards
The apple maggot (Rhagoletis pomonella) is indigenous to North America
and has been found in all Canadian provinces with the exception of Newfoundland.
It is a quarantine pest in Canada, especially widespread throughout eastern
Canada, causing fruit damage and significant economic losses. Organic
apple growers have a very limited control material list to select from;
premature drop and fruit injuries caused by apple maggots can reduce saleable
crop by as much as 75 %. To date, the only apple maggot control product
registered is Surround WP. Surround WP is a particle film kaolin clay
product, very dusty to work with and creating an unpleasant work environment.
Our research on apple maggot control first received funding from the
Pest Management Centre in 2007. Six research trials, two in Ontario and
four in Nova Scotia, were conducted in 2007 to test the efficacy of an
organic product, GF-120 Naturalyte Fruit Fly Bait (active ingredient:
spinosad). This project has shown positive results. The Ontario Ministry
of Agriculture, Food and Rural Affairs and Agriculture and Agri-Food Canada
in Nova Scotia have prepared a rationale leading to an emergency use registration
of GF-120 in 2008 for the suppression of apple maggot in organic apples
in Nova Scotia, New Brunswick, Prince Edward Island, Ontario and Saskatchewan.
In addition, a complete minor use label expansion has been submitted to
the Pest Management Regulatory Agency to seek eventual, full registration
of GF-120 for apple maggot control on apples in Canada.
Funding obtained in 2008 from the Pest Management Centre has allowed
research to continue; the objective was to optimize the delivery of this
control product to suppress apple maggots in organic orchards.
In Ontario, a trial was carried out in a commercial ‘McIntosh’
orchard to refine application methods for the maximum distribution of
GF-120 within tree canopies and to prune large-sized trees for better
penetration of GF-120 into inner tree canopies. In Nova Scotia, three
trials were carried out in research orchards. The effectiveness of applying
GF-120 at two different application intervals(7-day and 14-day), was evaluated
in a seedling orchard; The potential for using perimeter sprays or alternate
row spraying with GF-120 was tested in ‘Cortland’ and ‘McIntosh’
orchards.
The goal of this research is to reduce apple maggot pest populations
yet at the same time minimize the amount of control product used. Apple
maggot pest pressure was between 31 -42 % in all the orchards in this
study with the exception of the seedling orchard, where infestation reached
69 %.
Results suggested that in orchards of very large trees with dense canopies,
uniform distribution and good penetration of GF-120 into tree canopies
are extremely important to attain effective apple maggot control. In orchards
with severe pest pressure and resident infestations throughout the orchard,
GF-120 should be applied every 7-10 days following label recommendations
for adequate apple maggot control. If the apple maggot is not a resident
pest, 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.
