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Horn Fly Control
Demonstration
(Site 28)
Project Summary: Horn flies are a problem on pastured cattle from May
– September each year. It is estimated that weight gains are reduced by up to
18%. Usually the flies are controlled by applying insecticide – impregnated
eartags to the cattle. In recent years horn fly populations throughout western Canada have been developing resistance to the chemicals
used in the eartags. Therefore, we wanted to build a horn fly trap. Luckily we
were able to find a trap that was already built and used it in this project.
The cattle had to walk through the trap to get to the water supply. The trap
did remove the flies as we had hoped and helped to eliminate the need for
insecticide type eartags.
Objectives:
- To demonstrate to producers how to build a horn
fly trap.
- To determine the effectiveness of this type of
horn fly control method.
- To evaluate the cost effectiveness of this type
of horn fly control system versus eartags.
Cooperator: Ralph Maull
Cooperating
Agencies: M.D. of Wainwright A.S.B.
Project Advisors: Wyett Swanson
Dennis
Berrnaert, Man.
Doug Colwell,
Ag. Canada
Hugh Philip,
B.C. Agriculture
Legal Land Location: SE-11-42-4-W4
Background/ Project
Description:
The horn fly trap was set up
in 2001 and 2002 in a 158 acre pasture with a cross fence separating the water
source from the rest of the pasture. This forced the 26 Horned Hereford
cow/calf pairs and 1 bull to travel through a gateway to get to water. The horn
fly trap is 3’ x 8’ long. It was placed in the middle of the gateway. Panels
were attached at each side of the horn fly trap eliminating any alternative
route through the gate, so the cattle had to go through the horn fly trap. Two
canvas flaps were placed at the front and the back of the horn fly trap to
prevent light entering the trap and to remove flies off the cattle’s back. The
flaps brush the flies off the animal’s back and
because it is dark in the trap the flies are attracted to the light screens.
The flies fly into the tiny holes that are in the first screen trapping them
between two screens. The flies cannot escape this area and eventually die.
To assess the effectiveness
of this horn fly trap the cattle were observed with binoculars every week
throughout the June to August period. The animals in the herd were viewed and
given a percentage value as to the amount of horn flies covering the animal’s
back, stomach and sides. The horn flies can be distinguished by their shiny,
glossy wings as they sit on the animals. If the horn fly population did not
decrease throughout the summer then the trap was not very effective, but if the
population did decrease it was a success.
Observations:
In 2001, the flies were estimated
to be at 25% body coverage on the cattle in this demonstration. A week later it was down to 10-15% coverage
on these cattle. After the 3rd week of this trial the fly count was
down to 5-10% coverage of the body of the animals. This amount of flies decreased as the weeks
went on. In the flytrap many different species of flies were identified.
In 2002, the flies were
estimated on July 23, at a body coverage on the cows
of about 20% and on the bull it was closer to 25-30% body coverage. A week later,
after the cattle had access to the trap, on July 30 there was around 15%
coverage on the cows and about 20% coverage on the bull. Once again this year various species of flies
were trapped in the horn fly trap. This demonstration unfortunately was cut
short. First we had to wait longer for
the horn fly population to build due to the cool conditions earlier in the
season. Then, due to the drought, the
cattle were moved to another pasture. So
our observation period was quite short.
We still feel this trap is a
very effective method of removing horn flies from livestock.
Future Plans:
We are extremely pleased
with how well this horn fly trap worked this season, even if it was for a very
short period of time. It is our hope to try it again next year with the same
animals being used.
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