MANAGEMENT PIH-121
PURDUE UNIVERSITY. COOPERATIVE EXTENSION SERVICE.
WEST LAFAYETTE, INDIANA
A Guide for Fly Control Around Swine Facilities
Authors
John Campbell, University of Nebraska
Ralph Williams, Purdue University
Roger Moon, University of Minnesota
Reviewers
Anthony and Joyce Bornhorst, Ft. Loramie, Ohio
Chris M. Christensen, University of Kentucky
Mark and Tammy King, Johnsonville, South Carolina
William F. Lyon, The Ohio State University
Introduction
The house fly is the primary nuisance fly associated with
hogs, although other species of the filth fly complex (little
house fly, soldier fly, stable fly, and syrphid fly [rat-tailed
maggot]) may also be numerous at certain times of the year. In
addition, species of the biting fly group (mosquitoes, biting
gnats, black flies, and tabanids [horse and deer flies]) may be
pests if the hog unit is within the flight range of their aquatic
breeding areas. Members of this group are blood-feeders and, when
adults emerge, they must find animals on which to feed.
The biting fly group breed along or in streams, waterways,
flooded pastures and, if they are not properly managed, in animal
waste holding ponds. Holding ponds should have steep slopes and
vegetation should not be allowed to grow near the water or on the
pond slopes. The solids in a holding pond should be removed when
no longer covered with liquid. Flooded pastures should be drained
or treated for mosquito control.
Most filth fly species deposit eggs in moist, decaying,
organic matter including swine manure. The life cycle is composed
of an egg, larva, pupa, and adult stage. During the summer, a
cycle can be completed within 10-14 days. The reproductive poten-
tial for house flies is very high with females depositing 400-600
eggs during their life span of 2-3 weeks.
Research indicates the effect of house flies and other filth
flies on weight gains and feed efficiency of pigs is negligible.
However, the possibility for disease transmission and for nui-
sance lawsuits generally makes the control of these pests a pru-
dent management strategy.
Control Recommendations
The first consideration for a filth fly management program
should be sanitation. If the doors, openings to aeration fans,
and the drop down sides are screened, the number of flies enter-
ing a building will be reduced.
Animal waste, bedding, and spilled feed should be removed at
least weekly. Disposal of the waste is critical to fly manage-
ment. If the material is spread on fields, it should be spread
thin enough to dry quickly or be incorporated into the soil; oth-
erwise, it could become a fly breeding source. If the manure is
stacked, it should have sharply sloped sides to prevent water
penetration, or it should be covered with black plastic which
creates enough heat to destroy fly eggs and maggots. Every swine
facility, regardless of type, has some sanitation problem unique
to that facility. The key to fly management is the prevention or
removal of fly breeding sources. Proper drainage, prevention of
wet areas around faulty waterers, and management of animal waste
will greatly reduce fly breeding areas.
In slatted floor housing, where animal waste is handled as a
liquid, the problem area may be in the waste pits. If the liquid
waste is not agitated, the material will crust at the surface and
flies will breed in the crust. Mechanical aeration, adding water
and preventing the pits from overfilling (no closer than 1 ft. to
the slats) prevents the formation of a crust. Feed and animal
waste may accumulate at the top and sides of the pit. The use of
high pressure washes at 2-wk. intervals should prevent this prob-
lem. Regular removal or drainage of animal wastes is essential to
efficient manure management in housing systems.
The ``Cargill''-style open-front type buildings are designed
to facilitate easy cleaning if a high-pressure water system is
available to wash the manure off the apron into drainage chan-
nels. Drainage of solids into a holding pond may become a problem
if the slope is less than 3 degrees. Feed accumulation around,
under, and behind feeders may create fly breeding areas.
The use of straw or other organic material for bedding in
farrowing houses and in sow-nursing pig units is often a major
fly source. When wet, this bedding provides ideal house and
stable fly breeding so it should be removed at 7 to 10 day inter-
vals. The sheds in a sow-nursing pig unit should have removable
or hinged tops for easy cleaning.
Dirt-pen systems (pastures) have few fly problems if the
housing is periodically cleaned. Sudan grass, Sudex, or small
grains can be planted seasonally in the pens; this provides some
feed and utilizes the animal manure as fertilizer.
The worst fly problems often occur in pig units that utilize
converted farm buildings (calf shed, poultry house, wing of a
barn, etc.). These facilities are seldom designed to handle the
animal manure efficiently. Good drainage for liquids and a
minimum storage time for wet solids of 1 to 2 weeks is necessary
to prevent fly breeding.
Insecticide Recommendations
The insecticide label provides information on treatment
rates, mixing directions, and restrictions such as minimum treat-
ment age, treatment-slaughter interval, and treatment-farrowing
interval. Avoid contamination of feed and water sources with any
insecticide. The insecticide recommendations made by Extension
personnel should be reviewed annually because of possible label
cancellations, new products, or new restrictions on use of old
products.
Insecticides can be applied in several different ways for
fly control at hog facilities. The most efficient and dependable
method for fly control is the application of surface sprays on
fly resting areas. House flies rest at night on walls, ceilings,
and rafters inside buildings or under the eaves and on outside
walls. Flies that rest on an insecticide-treated surface absorb
lethal quantities of insecticide. Fly specks indicate resting
areas of flies. Residual sprays should be effective for 7 to 10
days on shaded surfaces unless washed off or covered by dust.
Rotate between classes of residual insecticides two or three
times during the fly season to delay the development of
insecticide-resistant fly populations. Residual insecticides
include: dimethoate (CygonO), diazinon, malathion, methoxychlor,
stirofos (RabonO), permethrin (EctibanO, AtrobanO) and fen-
valerate (EctrinO). The label will contain mixing instructions
and application rates. Generally sprays are applied to the point
of runoff with either hydraulic or hand sprayers.
Short residual knockdown or area sprays can also be utilized
in a fly control program. Area sprays include dichlorvos (Vapona
DDVP), naled (DibromO), synergized pyrethrins, malathion, per-
methrin (EctibanO, AtrobanO), and fenvalerate (EctrinO). These
sprays are applied as a mist and the insecticide droplets kill
flies they contact. Area sprays can be applied with mist blowers,
hydraulic sprayers, or foggers. An area spray treatment should
cover the space in and around the entire facility, including all
shaded fly resting areas such as trees, weeds, shady sides of
buildings, and even the edge of fields.
Insecticide baits may be used to reduce fly numbers indoors,
but will not provide adequate overall fly control if used
exclusively. Baits can be used inside swine buildings, offices,
and feed handling facilities but care should be taken to assure
that pets or pigs do not have access to them. Baits can be pur-
chased ready-to-use (Golden MalrinO) or some of the residual
spray insecticides (methoxychlor, diazinon, malathion) can be
mixed with water and sugar and used as a slurry for a bait.
Larvicides and feed additives can be employed for fly con-
trol. Larvicides are sprayed on fly breeding areas and feed addi-
tives are fed to an animal and pass through the digestive tract
into the manure. Neither method is very effective because the
acidity of the fly breeding material breaks down the insecticide
rapidly. A second consideration is that resistance generally
develops more rapidly when immature insects are treated. Almost
any of the insecticides listed as residual sprays can be used as
a larvacide. Stirophos (RabonO) is the only feed additive
registered for use with pigs.
Two methods of control can be used simultaneously. Area
sprays can be rotated with residual sprays. Residual sprays will
last approximately 7 to 10 days and the surviving, newly emerged
flies can't deposit eggs for approximately a week. A knockdown
spray can be applied when fly numbers start to increase and then
in another week a residual spray can be applied to fly resting
areas. This alternation of control methods should delay the
development of insecticide resistant flies.
Biological control, which would utilize fly pupal parasites
(wasps), has potential for integration into a filth fly control
program. However, commercial companies seldom have the research
basis for determining which native parasite species will provide
the best control.
Summary
An effective fly control program requires a comprehensive
animal waste management plan. Reliance on insecticides alone is
costly, ineffective, and usually leads to the rapid development
of insecticide-resistant fly populations. Each hog operation will
have some fly breeding areas unique to that operation, and the
key to good fly control is to find and eliminate those areas.
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Reference to products in this publication is not intended to
be an endorsement to the exclusion of others which may be simi-
lar. Persons using such products assume responsibility for their
use in accordance with current directions of the manufacturer.
NEW 6/89 (5M)
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Cooperative Extension Work in Agriculture and Home Economics,
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