Quick Fly Control Instructions
Step 1
Wait, don’t release your Fly Predators until you see at least 10-20 moving around.
They are shipped in the inactive pupal (cocoon) stage which are the little black
things. Within 5 days after arrival during the summer (up to 14 days when cooler)
they will start to emerge. They look like tiny little ants with wings. When it’s
cool, keeping them in a warmer area (75-85ºF) will speed up their emergence. When
it’s hot keep them under 100ºF and out of direct sunlight when in the bag. After
they begin to emerge release them as soon as possible. Holding them longer than
5 days after first emergence will reduce their effectiveness. Call us if you see
no signs of life after 10 days from the date shipped in summer or after 14 days
from date shipped when its cooler.
Step 2
Release your Fly Predators by sprinkling them around each area where there
is moist manure. Divide the Fly Predators proportionally by how much manure is in
each area. Put some in the manure corner of corrals, some in the barn, some at the
manure pile (only the outside 6” supports fly reproduction, the rest is too warm),
as well as some in pasture areas, arenas, grassy areas and dry lots. Pay particular
attention to moist areas, leaky faucets, water troughs, etc. Fly Predators will
disperse themselves up to 150 feet so putting them nearby manure is good enough.
Flies can’t reproduce in dried manure so if it’s spread in fields and completely
bone dry, don’t put Fly Predators there.
Step 3
Watch Out for ants, birds and chickens all of which love to eat the pupae that some
of the Fly Predators are still in. Release them away from ant areas. If you have
free range chickens put the Fly Predators in open sacks hung above chicken level.
Important! Keep pesticide sprays away from Fly Predators. If you have to spray a
horse move them away from any manure area. To get the last few flies, use traps,
sticky paper or bait. Pest flies travel 1/4 mile or more. If you have nearby neighbors
with animals suggest they use Fly Predators too, for best control for everyone in the area.
Detailed Fly Control Instructions
Factors To Consider Before The First Release
Existing Fly Problem Fly Predators attack the fly’s pupa (cocoon) stages only.
They do not attack the adult pest flies. Thus, the adult flies currently existing
must either be removed by supplemental methods or tolerated until they live out
their short life span of about 21 days.
Remember, it is always better to start your releases of Fly Predators early in the fly
season and prevent a buildup of flies, than to have to remove the adult flies after they
have attained intolerable levels. Although the quantity of Fly Predators recommended are
generally suited for most situations, occasionally larger quantities are needed for severe
fly problem areas.
At the height of the fly breeding season you may need an extra shipment or two so that the
Fly Predator population can keep up with the pest flies which reproduce up to 9 times faster.
(That’s why we provide Bonus shipments). The female Fly Predator lays about 75 eggs with 14
to 20 days to emergence while each pest fly female can lay 500 eggs with as few as 8 days to
emergence. It is due to this large reproduction capacity of the pest fly that the Fly
Predators are not self-sustaining to a degree high enough to maintain full fly control and
thus need to be supplemented each month of the fly season. Some of the Fly Predators will
overwinter just as the pest fly does in the cocoon stage and each year they will become better
established, thus control improves with time.
Ants If you have many ants in the area where you are going to put the Fly Predators,
it is best to eliminate them first, as they will eat the Fly Predators.
Birds Fly Predators inside the pest fly pupa are very appealing to birds. If birds
or chickens are eating the Fly Predators before they emerge from the fly pupa, do not
spread the Fly Predators in the manure but leave them in the opened pouch hung above
chicken level on a nail or thumb tack. This way they will fly to the manure as soon as
they emerge. In about a week or 10 days pour the remaining contents out. Another method
of protecting your Fly Predators until they emerge is to cover the fly pupa lightly
with leaves, dry manure or dirt.
Insecticides Unlike pest flies which can often be only slightly affected by insecticides,
Fly Predators are very susceptible to these. Thus, if sprays are currently being used and
the over spray will fall on a large part of the manure inhabiting Fly Predators, the sprays
should be discontinued.
Generally, feeding internal larvicides to your animals will not adversely effect the
Fly Predators. Occasionally manure will have enough poison residue left in it from past
heavy spraying to completely kill your beneficial insects. The only solution here is to
clean out and start over again.
Storage Procedures For Fly Predators
If you need to store your Fly Predators before releasing them, simply keep them in their
pouch which is sealed, but breathable. They will keep this way for 3 days after they
start emerging without any adverse effects. If absolutly necessary to hold for a
longer period of time put the pouch containing the Fly Predators in the refrigerator
as soon as it arrives. Their productivity slowly decreases if kept longer than
about 5-7 days. Do not allow them to freeze.
Integrated control
Integrated control is the augmenting of biological control with other methods which
gives the highest degree of fly control that will not harm your beneficial insects.
Several of these methods that have been used successfully with Fly Predators are
traps, sugar based fly baits, fly papers, electric and black light fly traps, and
spraying non-manure areas where flies congregate, such as rafters in the evenings,
fence rails and barn sides in the morning sunshine, shady places in the heat of
the day, etc.
Sometimes the degree of fly control achieved is not as high as desired due to flies
migrating in from neighboring breeding areas. Pest flies are hardy fliers and easily
migrate up to a quarter mile a day, sometimes up to one half mile. We often see people
who are very conscientious about fly control on their property but are surrounded by
neighbors who do little or almost nothing on those lines. In these cases a high degree
of fly control is almost impossible to achieve (regardless of the methods used) unless
the neighbors also participate. We will gladly supply fly control information to
your neighbors if desired.
Manure Management Tips
The most ideal manure management program is to clean frequently and spread the manure
thinly on fields where it will dry quickly. The pest flies larvae are highly susceptible
to this drying and will not pupate (form their cocoon) properly unless the medium they’re
in is moist. If frequent cleaning is not practical and the manure accumulates to more
than 2 or 3 inches deep, it should be stacked in a large pile. This will reduce the
surface area and the heat generated in the core of the pile will force the pest fly larvae
to the outside 6 or so inches.
Fly Predators live their entire life on or near manure and are partially transported
wherever it goes. Cleaning will disturb the adult Fly Predators and they will fly off
and migrate to new manure deposits. You may lose someof the next generation of Fly
Predators that have not yet emerged from the fly pupa, but they will travel along to
wherever the manure is taken and give control to that area. Often it is best not to
clean down to the ground, but leave an inch or two of manure, this will also help your
natural population of beetles and mites which also help control pest flies.
One important fly-breeding site that is often overlooked is moist decaying vegetable matter.
Rotting hay and straw spilled behind feeders and even lawn clippings offer an excellent
breeding site for pest flies. This vegetable matter should either be removed or spread
out so that it will dry.
Another fly-breeding site that is often a problem is where livestock urinate on their manure,
keeping it moist. If removal is not practical then sprinkle with hydrated lime (available
from farm supply houses). This prevents flies from breeding and helps the odor. In fact,
it is a good practice to put lime on all sites where your livestock urinate, but do not put
it on manure where Fly Predators will be.
How To Recognize The Fly Predators And How Long Until They Are Established
When you see the emerged Fly Predators in their shipping pouch that is their full
adult size. When the Fly Predators have emerged, the fly puparium, in which they are
shipped, will still be intact, but with a little hole in it about 1/32” in diamater.
One can inspect for the escape holes in the pest fly pupal case to determine if the
Fly Predators have emerged.
When Fly Predators become established you will be able to see the tiny Fly Predators
on moist manure piles. Although there are many small gnat like insects commonly found
on the manure, the body shape, color and behavior of Fly Predators allows an experienced
eye to detect them. One common misconception is that the smaller flies found around manure
are “baby flies”. They are not baby flies, but different species of pest flies.
Like butterflies, Fly Predators and pest flies develop through a complete metamorphosis,
from the egg, to the larval stage, and then emerging from the pupal or cocoon stage as
full sized winged adults, remaining that same size for life. The pest fly’s egg and larval
(maggot) stage are spent in the manure, but just before entering into the pupal stage the
larva crawls up to 10 feet away from the manure and digs itself into the soil if possible
to undergo its metamorphosis. It is the pest fly’s pupal stage that the Fly Predators attack.
The female Fly Predator digs down and lays one or more of her eggs in the buried pest fly
pupa. The female Fly Predator’s egg quickly hatches into a larva and starts feeding on the
immature pest fly pupa. Then it undergoes its metamorphosis from pupal stage into full size
adult. All of this takes place within the pest fly pupal case and the Fly Predator emerges
to start the cycle over again. The time it takes to establish biological control is often
longer than expected, but it is well worth the wait. It is not unheard of for biological
control to take a season to become fully effective, but once Fly Predators are established,
pest flies will never build up to nuisance levels.
Live Delivery Guaranteed
Your Fly Predators should emerge within 3-10 days after delivery if they are maintained at
approximately 80ºF. Often their emergence will be delayed as their development time is very
temperature dependent and they are often kept at temperatures lower than 80ºF during shipping.
If at 14 days past the arrival date they still have not emerged we will gladly send you
another shipment. Please call customer service at 1-888-562-4241.
Due to the minute size of Fly Predators, we measure their numbers by the volume of the pupa
cases they are delivered in. Since one to seven Fly Predators will emerge from each pupa case,
depending upon the species, the volume of your shipment may vary from time to time, although
the number of Fly Predators enclosed will be the same. Normally we enclose more Fly Predators
than ordered to insure live delivery of the quantity requested.
Copyright Spalding Laboratories, Inc. 2008 FLY PREDATORS is a trademark of Spalding Labs