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Wrangling on the Range #153

Controlling Flies



by Frank Marchetti

Using new technologies and being proactive is the best approach
for fly control

When springtime arrives the earth is warmed up and it bounds back
to life. Most of that life is very welcome, but some of it we
would rather do without. One such example we equine lovers have
to deal with are those pesky flies. Why do horses and flies go
hand in hand anyway? The answer is that horses provide flies with
an abundance of their favourite breeding ground: manure. if we
can limit fly populations where they breed by introducing natural
enemies, we can achieve a long-term solution without any harmful
side effects.

Fly life-cycle

Adult 'filth' flies (stable flies and house flies) deposit eggs
in organic matter, such as manure and wet feed. This is an
excellent food source for maggots that hatch from the eggs. As it
goes through its development, each larva (maggot) eventually
trans forms to the non-feeding pupal stage. During this time     
it forms an armor-like coating, which is developed from the
larval skin and protects the pupa during its metamorphosis to an
adult fly. Finally the adult fly emerges from the
pupa, and can then repeat the life cycle.

Why are flies so hard to control? 

When we talk about flies as pests, what we are really referring
to is the adult stage of the fly - the stage that annoys and
harms by spreading disease among horses through tainted blood
and/or mucus. Therefore, traditionally, most of the focus has
been on controlling this adult stage, usually with pesticides.
The problem with this approach is that it is only a band-aid
solution - you may kill the adult flies but there are three other
stages developing at the same time; egg, larva, and pupa. Once
they reach maturity you have the same problem all over again, and
it doesn't end until the tempera   tures are too cold for insect
activity. Without any control measure during warm weather, fly
populations can become unbearable.

How to control flies?

Gone are the days of using strictly pesticides for pest control.
Industry experts, government officials and scientists all agree:
IPM brings the best results. IPM stands for integrated Pest
Management - a system of using all of the techniques available
for pest control. The techniques used are Biological, Cultural,
Mechanical, and Chemical. They all have their effectiveness but
work best synergistically.

Cultural, mechanical, and chemical control

Cultural methods are generally related to sanitation - the
cleaner your stable, the fewer flies you will have. Stalls should
be cleaned daily, and the manure piled away from any buildings.
Bedding should be changed and refreshed regularly and stalls let
to air-dry occasionally. Stalls should also be thoroughly cleaned
and disinfected seasonally. Finally, the manure pile should also
be removed regularly.

Mechanical methods are physical devices like sticky rolls ind
string, and solar fly traps. They're non-toxic and help reduce
adult fly populations. These products can be found at your local
co-op or hardware store.

Chemical methods bring a fast reduction of adult flies but do
nothing to combat the immature stages. They bring quick relief
but do not provide a good long-term solution. Also, there are
many harmful side-effects with chemical use:

* Pesticide resistance: where pesticides lose their
* Harmful effect on non-target species: sometimes beneficial
organisms are harmed.
* Environmental (nature) contamination: soil degradation and
water table pollution.
* Worker (applicator) safety.
* Owner, handler and animal environment.

Still, chemicals can be part of an effective program as long as
they are not relied upon too heavily. Products such as fly bait,
a granular substance impregnated with a synthetic pheromone
(attractant) and pesticide can help keep populations low and are
not as bad as spraying structures.

Biological control

This method introduces natural enemies of pests that
instinctively prey upon or parasitize them. The industry is
heavily regulated and any commercial products must be indigenous
and shown not to be harmful to any other non-target organisms
before being made available. For flies, insects known as 'fly
parasites' are now commercially available and being successfully
used. When fly parasites are released where flies breed (manure),
they instinctively find and parasitize the fly pupa. injecting an
egg inside it. The egg soon hatches into a fly parasite larva,
and it consumes and grows inside the fly pupa, eventually killing
it before completing its own life-cycle and emerging as an adult
fly parasite. So now you have killed the fly before it has even
had a chance to become a pest! That is the beauty of using
natural enemies such as fly parasites.
There are two keys to the successful use of fly parasites: start
early before you have fly problems, and introduce them regularly
throughout the year. The fly still has two major reproductive
advantages over the fly parasite: its egg laying capacity is ten
times that of the fly parasites, and its development time (from
egg to adult) takes only half the time. This means that one
generation of flies is much greater than one generation of fly
parasites. Therefore you must start early and never give the
flies a chance to get the upper hand by having regular
introductions. The fly parasites are mixed with. wood shavings
and are sold in 'colonies' of 10,000 per bag. The bags are simply
released in horse stalls, manure piles, and other areas where
manure and decaying organic matter is  found. They are completely
safe for both human and animal health, and are economical and
easy to use. The amount that you need depends on the number of
horses that you have - the more horses, the more manure, the more
flies, the more fly parasites Treeded. The main thing to remember
is to start the program early, before you have serious fly

Frank Marchetti is the General Manager of Bugs for Bugs, located
in Guelph, Ontario. For more information on fly parasites, you
can contact Bugs For- Bugs at 1-866-577-1117, or

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