Prevention and Control
Effective mouse control involves sanitation, mouse proof construction and
population reduction. The first two are useful as preventive measures. When a
mouse infestation already exists, some form of population reduction is almost
always necessary. Reduction techniques include trapping and poisoning.
Sanitation. Mice can survive in very small areas with limited
amounts of food and shelter. Consequently, no matter how good the sanitation,
most buildings in which food is stored, handled or used will support house mice
if not mouse-proofed. Although good sanitation will seldom eliminate
mice, poor sanitation is sure to attract them and will permit them to thrive in
greater numbers. Good sanitation will also reduce food and shelter for existing
mice and in turn make baits and traps more effective. Pay particular attention
to eliminating places where mice can find shelter. If they have few places to
rest, hide or build nests and rear young, they cannot survive in large numbers.
Mouse-Proof
Construction. The most successful and permanent form of house
mouse control is to "build them out" by eliminating all openings
through which they can enter a structure. All places where food is stored,
processed or used should be made mouse-proof. Dried grain and meat products
should be stored in glass jars, metal canisters or other resealable airtight
containers.
Seal any openings larger than 1/4 inch to exclude mice. Steel wool mixed
with caulking compound makes a good plug. Patching material needs to be smooth
on the surface to prevent mice from pulling out or chewing through the patching
compound. Seal cracks and openings in building foundations and openings for
water pipes, vents and utilities with metal or concrete. Doors, windows and
screens should fit tightly. It may be necessary to cover the edges with metal
to prevent gnawing. Plastic sheeting or screen, wood, rubber or other gnawable
materials are unsuitable for plugging holes used by mice
Traps. Trapping is an effective control method. When only a
few mice are present in a building, it is usually the preferred control method.
Trapping has several advantages: (1) it does not rely on inherently hazardous
poisons, (2) it permits the user to make sure that the mouse has been killed
and (3) it allows for disposal of the mouse carcasses, thereby avoiding dead
mouse odors that may occur when poisoning is done within buildings.
The simple, inexpensive wood-based snap trap is effective and can be
purchased in most hardware and grocery stores. Bait traps with peanut butter,
chocolate candy, dried fruit or a small piece of bacon tied securely to the
trigger. Set them so that the trigger is sensitive and will spring easily.
Multiple-capture live traps, which can capture several mice once set, are also
available in some hardware and feed stores. Set traps close to walls, behind
objects, in dark corners and in places where evidence of mouse activity is
seen. Place them so that mice will pass directly over the
triggers as they follow the natural course of travel,
usually close to a wall. Traps can be set on ledges or on top of pallets of
stored materials if mice are active in such locations. Use enough traps to
eliminate the rodents quickly. (Using too few traps is a common error by
individuals attempting to control mice.) Mice seldom venture far from their
shelter and food supply, so place traps no more than 10 feet apart in areas
where mice are active. Leaving traps unset until the bait has been taken at
least once (prebaiting) often increases the success of trapping. An alternative
to traps are glue boards, which catch and hold mice attempting to cross them in
much the same way flypaper catches flies. Place glue boards along walls where
mice travel. Two or three glue boards placed side-by-side (or the larger glue
boards used for rats) will be more effective than individual boards. Do not use
them where children, pets or desirable wildlife can contact them. Glue boards
can be placed inside tamper-resistant bait boxes in exposed locations. Glue
boards lose their effectiveness in dusty areas unless covered and extremes of
temperature also may affect the tackiness of the glue. Glue boards are
sometimes used to catch a mouse that is wary of snap traps.
Poison Baits (Rodenticides). Rodenticides are poisons that
kill rodents. They can be purchased in hardware stores, feed stores, discount
stores, garden centers and other places where pesticides are sold. Do not buy
unlabeled rodent baits from street vendors or other uncertain sources. Do not
purchase baits that have an incomplete label or one that appears to be
“homemade.”
“Building ou“Building out” rodents and trapping are the most effective control
methods. Rodent baits should be used only to supplement these methods. If there
is a repeated need to use baits, it is likely that sanitation and
mouse-proofing should be improved. Remember that rodent baits are poisons. If baits are used indoors, be
sure they are labeled specifically for interior use.
The active ingredients in baits are used at very low levels, so bait shyness
does not occur when using properly formulated baits. Most of these baits cause
death only after they are eaten for a number of days, although some types can
cause death following a single feeding. Make sure that ailable continuously until mice stop feeding. Depending on the number of
mice, this may require up to three weeks.
Bait Selection and Placement. Baits are available in several
forms. Grain baits in a meal or pelleted form are available in small plastic,
cellophane or paper packets. These sealed "place packs" keep bait
fresh and make it easy to place the baits in burrows, walls or other locations.
Mice gnaw into the packet to feed on the bait. Block style baits are also very
effective for most situations. Proper placement of baits and the distance
between placements is important. Place baits in several locations no farther
than 10 feet apart and preferably closer. For effective control, baits or traps
must be located where mice are living. Use of tamper-resistant bait stations
provides a safeguard for people, pets and other animals. Place bait stations
next to walls with the openings close to the wall or in other places where mice
are active. When possible, secure the bait station to a fixed object to prevent
it from being moved. Clearly label all bait stations "Caution—Mouse
Bait" as a safety precaution.
Sound and Electronic Devices. Although mice are easily
frightened by strange or unfamiliar noises, they quickly become accustomed to
regularly repeated sounds and are often found living in grain mills or
factories and other noisy locations. Ultrasonic sounds, those above the range
of human hearing have very limited use in rodent control because they are
directional and do not penetrate behind objects. Also, they lose their
intensity quickly with distance. There is little evidence that sound of any
type will drive established mice or rats from buildings because they rapidly
become accustomed to the sound.
Control by Cats and Dogs. Although cats, dogs and other
predators may kill mice, they do not give effective control in most
circumstances. In fact, rodents may live in very close association with dogs
and cats. Mice and rats may obtain much of their diet from the pet's dish or
from what pets spill.
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