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Grape Grower's Notebook
June 3, 1999 |
Bird Repellent Editor's note: We have yet to try the relatively new bird repellent "ReJeXiT" , but here are two reports from Maryland growers on the spray material and one other
interesting device called "Bye Bye Birdie".
These articles are from the Maryland Grapevine, Vol. 18-1, and are available on line. The articles appear here for your convenience. They are available for downloading, but they
are copyrighted by the Maryland Grape Growers Association. Also, the site of the manufacturer of ReJeXiT is http://www.rejexit.com/.
NEW BIRD REPELLENT THAT WORKS
by Jim RussellAnew product, ReJeXiT-AG145, became available last year that may give us
back the freedom from bird depredations that Mesurol provided until its
registration was withdrawn. The active ingredient is methyl anthranilate,
the substance which, in natural form, is one of the flavor ingredients of
Concord grapes. The synthetic material is used in
artificial-grape-flavored bubble gum. It is a recognized food additive,
non toxic and benign to the environment. Birds intensely dislike the
flavor although ingesting it does not harm them. The material was first
released as a bird repellent to keep geese away from golf courses and areas
around swimming pools. After proving its effectiveness, EPA approval was
obtained for use on grapes. I used it in 1997 as my only defense against
birds and it was effective. Effectiveness
My first application of ReJeX-iT was when my earliest red grapes, Foch and
Cascade, started to color enough to attract the birds. Bird damage started
to be apparent on vines at the end of a row closest to my neighbor's trees.
I applied ReJeX-iT, 3 fluid ounces per gallon, using a pump-up hand sprayer
with high pressure and the nozzle set to give the finest spray I could get.
Application was to the clusters only from both sides of the row.Application rate was one gallon of mixed spray per 240 feet of row or, for
my eight-foot spacing between rows, 22.7 gallons per acre. Bird damage
stopped almost completely but a few berries got "sampled" before the birds
decided the grapes were no longer edible. The grapes tasted horrible and
smelled as bad. After a week, I could not detect any taste but a little
smell still lingered, especially on my hands if I handled the clusters.
After 10 days, sampling had started again and damage had begun to build. A
second spraying using 4 ounces per gallon stopped the damage. Again, a
little smell was evident after a week but was gone completely after two
weeks. No damage occurred at all until after the third week and damage was
never bad enough to warrant a further spraying before harvest some five
weeks after the second spraying.
Two weeks after the second spraying of Cascade and foch, it was noticed
that Seyval was getting ripe enough to attract birds. Seyval and the rest
of the vineyard were sprayed using 6 ounces of concentrate per gallon of
spray, hoping to make it last even longer. There was no appreciable bird
damage thereafter except for Cabernet Sauvignon vines at the end of the row
near trees about the middle of October. A quick spraying of Cabernet at 4
ounces per gallon stopped the damage before any measurable loss of crop. Cost
As of last year, the ReJeX-iT concentrate cost was $199.50 for two 21/2
gallon plastic jugs (the minimum order). I split my order with Nick
Petrucelli so my cost was $99.75 for 21/2 gallons or essentially $40 per
gallon. At six ounces of concentrate per gallon of mixed spray and at one
gallon of spray per 240 feet of row, it takes almost exactly one gallon of
concentrate per acre (with eight feet between rows - less for wider
spacing) so the cost is $40 per acre per spraying at the six-ounce/gallon
concentration. It would be only 2/3 of this at the four-ounce/gallon
concentration. Two spray applications certainly would be enough at the six-ounce
level and probably enough at the 4 ounce level. THIS IS FOR SPRAYING
CLUSTERS ONLY WITH AS LITTLE AS POSSIBLE WASTED ON THE FOLIAGE.
Caveats 1997 was an unusual year. The year started off with a normal population of
the bird types which nest in and around the vineyard. There were the usual
number of robins, cardinals, mocking birds, and blue jays, all of which are
fond of grapes. But by the time of my second spraying, something,
presumably the dry weather and the resulting decrease in food, had caused
most of the birds to go somewhere else. The number remaining dropped even
more by the middle of September when most of the grapes were ripe enough to
be attractive to birds. The large flocks of grackles, starlings, and
cowbirds which usually are the cause of greatest damage never did appear.
So the apparent protection toward the end of the season may not be as good
as it seemed. However, the few birds that did stay around did not eat the
grapes in spite of their lack of other food. Alternately, it may be that
the lack of edible grapes (due to the application of ReJeX-iT) may be the
reason the birds went somewhere else. It will take a more normal year to
be sure. On the basis of 1997 results, ReJeX-iT appears to be as good as
mesurol was and to have the same drawback; it is too expensive to tank mix
with other sprays and apply to the entire vine, foliage and all. However,
with a well-defined fruiting zone and nozzles set to cover only the
fruiting zone, it should be suitable for power spraying.
BIRD REPELLENTS: ANOTHER VIEW
by Jack Johnston
My experience with ReJeX-iT was limited to a number of rows in my vineyard
which we normally harvest for our own use (as opposed to the vast majority
allocated to our commercial buyers), plus a couple of outer rows which are
generally the heaviest hit by birds. Since the latter amounted to less
than 4% of the total delivered to our buyers, I didn't see this as imposing
any risk. As Jim observed, bird damage in general seemed unusually low this past
season, so it's hard to assess the actual deterrent effect of the material.
Also, the tried and true (if cumbersome) preventives, including mylar
flash tape and bird distress call devices, had been installed late in
August. A little damage had been observed on a few rows toward
mid-September. ReJeX-iT was applied, augmented by a surfactant (LI-700),
to the fruit zone of the selected rows on September 25, using 4 oz/gal in a
backpack sprayer. I could smell the stuff as it was being sprayed, and 24
hours later I could taste (but not smell) it on the grapes (but only
barely). A few days later I couldn't detect it at all, but the birds
apparently could, as no further damage was incurred to these rows until
October 3, when a few vines showed a little feeding activity. No further
repellent was applied, and the grapes were harvested on October 11.
Conclusion: the material seems to work. With the okay of our buyers, I
plan to expand the coverage this season for further testing. Whether it
will prove a satisfactory replacement for the defunct Mesurol remains to be
seen, and I intend to keep the other deterrents active until I'm confident
that they can be phased out. Currently, ReJeX-iT is available only through direct order from the
manufacturer, but wider distribution is apparently planned in the near
future. Bye Bye Birdie is a device which is suspended at a suggested height of 15
feet in the vineyard, and generates a magnetic field which is supposed to
disrupt the birds' natural sense of direction, causing them to become
disoriented and avoid the area. The sphere of effectiveness has a radius
of 70 feet. The best I could do was 12 feet in height, reducing this
coverage somewhat. I hung it in a region which showed bird activity and in
which no other deterrent was being used.
After a week or so, additional damage to the grapes had been noted, so I
called the company to discuss the matter. I was told that it sometimes
takes up to two weeks before the birds get frustrated enough to take their
feeding efforts elsewhere. They recommended that it be installed two weeks
prior to anticipated damage, before feeding habits become established.
After another week, there didn't seem to be any additional damage to the
vines within the sphere of effectiveness. But since the whole test got off
to a shaky start, it's hard to make a definite assessment. I will repeat
the test this year under more carefully controlled conditions, and report
the results in the winter Grapevine.
It's probably worth noting that at $50 a pop, this gadget may not be cost
effective for large vineyards.
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