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Aug./Sept. 2001
Blackbird Remedy in Sunflower?
A new biodegradable product called Bird Shield™
holds promise as a blackbird repellent.
A new biodegradable product—with an active ingredient, methyl
anthranilate, that is derived from grapes—holds promise as
a blackbird repellent in sunflower and other crops, such as sweet
corn.
Leonard Askham is hoping to secure state and federal
label approval this spring so that he can begin marketing his new
bird repellent, called Bird Shield™, for the 2001 growing
season. Askham, whose Bird Shield Repellent Corporation is based
in Spokane, WA, says his product was one of the first biochemicals
to be entered into the label approval process at the Environmental
Protection Agency.
How did Askham discover that a chemical component
in grapes repels birds? Askham explains that he spent 25 years researching
animal damage control as associate scientist at Washington State
University. One day, he learned from a wine grape producer in Washington
state that while birds were causing problems in the producer’s
wine grapes, the birds were leaving the concord grapes alone. Askham
began researching why. He isolated about a half dozen chemicals
present in concord grapes that were not present in wine grapes,
and further testing led to methyl anthranilate as the key chemical
that repels birds.
He began experimenting with the chemical on corn
in 1995, and in 1998 and 1999 conducted field trials on sunflower
in Forman, ND and sweet corn, in Olathe, CO, applying the product
by air. In 1998, trials were conducted on six sunflower fields near
Forman, four of which were treated. The trials were repeated the
next year with ten fields, six of which were treated. The remaining
plots, two in 1998 and four in 1999, were left untreated to compare
with treated plot results.
All of the fields were similar in topography and
contained cattail marshes where the birds roosted and drank. The
fields, including marshes, were treated twice, at seven day intervals
starting when the birds began to feed on the ripening ‘flowers.
Twelve sunflower heads were randomly harvested from the center of
each plot at the end of the trials. Each head was weighed, measured,
the area of damage recorded, and the seed removed.
Two applications of the repellent were sufficient
to move the resident population of blackbirds out of the sunflower
fields with no substantial damage to the crop (2.6% to 3.4%) compared
to damage in untreated sunflower that ranged from 78% to 90% (Figure
1). Harvest weight of sunflower in untreated plots ranged from 133
to 700 lb./A (344 lb/A average) while yield of treated plots ranged
from 1,430 to 1,909 lbs./ac (1,890 lb/A average).
The corn plot data indicated similar success:
when the crop was treated with the repellent ten days prior to harvest,
during both trial years, less than 1% of the crop was lost from
bird damage. Askham says the data indicates that the use of the
repellent, when applied when the birds begin to feed on these crops,
can be effective in reducing red-winged bird damage to both commodities.
The product is also environmentally safe, he says.
The field trials indicate no adverse effects on fish or resident
populations of ducks when the product is used as directed. And once
applied to a crop, it won’t leach or translocate. "These
are all arguments we had to prove to the EPA," says Askham,
including the fact that crops treated with the product aren’t
harmful to humans or livestock. "You would have to feed an
animal seven tons of treated product a day to see any effect,"
he says.
Bird Shield™ will also be labeled for use
to repel birds from buildings and residential areas. The product
is not effective on nesting birds, Askham notes. Since the product
is biodegradable, it must be used by a certain date.
The product contains 2.29 lbs. of active ingredient
per gallon. It should be applied on corn and sunflower at a rate
of one pint of concentrate (0.28 lbs ai) per acre by air. For corn,
the product should be applied 10 days before harvest, when the crop
begins to ripen, or when birds begin feeding, and reapplied at five-day
intervals until harvest, which should be five days after the last
treatment. For sunflower, application should begin when birds begin
feeding on the crop, and repeated as necessary to maintain repellency,
with a seven-day preharvest interval from the last treatment. Product
cost will be around $50 a gallon or between $6 and $7 per acre,
not including application.
Rick Hoistad farms near Forman, and it was his
fields where the sunflower trials were conducted. "We farm
near the Tewaukon Wildlife Refuge, and the blackbird activity that
carried over proceeded to nearly wipe us out," he says. Hoistad
tried virtually every blackbird control product on the market. "This
is probably as good as any alternative I’ve found. We’re
able to raise ‘flowers again with this product," he says.
One key aspect of treatment is that if resident birds can be kept
away early, then that will help prevent migrating birds from coming
in too. "I’ve seen them wipe out a quarter of land in
a matter of a few days," says Hoistad, who has become a product
distributor.
Wildlife Official: Independent Analysis Needed
Officials with the Wildlife Services Division
of the USDA/Animal and Plant Health Inspection Service in Bismarck,
ND, say they have seen commercial bird control products come and
go from the marketplace—but are cautiously optimistic about
Bird Shield. Although the product appears promising, independent
analysis is needed. "To be fair to growers, we want to give
it a good look," says one WS official. To confirm the product’s
effectiveness, USDA-APHIS intends to evaluate Bird Shield in its
own independent field analysis during the 2001 growing season. Since
total treatment costs could run about $25-$35 acre—$10 to
$12 for a treatment with application cost included, repeated two
or three times—more analysis is also needed on how the product
may be used most cost-effectively by producers in need of blackbird
control. "Maybe you don’t have to treat the whole field.
There’s still much we don’t know about this product,"
says one WS official.
Askham agrees that growers will experiment themselves,
particularly to save costs. "After all my years of R&D
with the product, I have learned that after it is released the growers
are the ones who develop the best way to use it," he says.
—Tracy Sayle |
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