Continued from page 1
After locating
main tunnel, open it with a shovel or garden trowel and set
traps in pairs facing
opposite directions. This is necessary in order to intercept
gopher coming from either end of
burrow. The box type is easier for most inexperienced trappers to set, but requires more excavation. Box traps are useful when
diameter of
gopher's main burrow is small (less than 2 1/2 inches) since small burrows will need to be enlarged to accomodate
box traps. All traps should be wired to stakes to prevent loss. After setting
traps, exclude light from
burrow by covering
opening with dirt clods, sod, cardboard, or some other material. Fine soil can be sifted through
edges to ensure a tight seal. If light enters,
gopher may plug
burrow with soil, filling
traps in and making them ineffective. Check traps often and reset when necessary. If no gopher is caught within 3 days, reset
traps in a different location.
Poison baits offer
quickest and most effective method of controlling a large gopher infestation. The most commonly used toxicants are chloraphacinone, strychnine, and zinc phosphide pelleted bait. Chloraphacinone,
lesser used of
toxicants, is a multiple dose anti-coagulant that prevents
normal process of blood coagulation ultimately causing death from internal bleeding. It has limited field use because of
necessity of making multiple applications in
same burrow system, but may be useful where an extra margin of safety is desired. The acute toxicants, strychnine and zinc phosphide, are
most used and most effective. Most baits are prepared on hulled wheat, barley, or milo grains, with wheat seeming to be
most preferred by
common Battae (T. bottae) gopher. Zinc phosphide baits are only accepted adequately in blended pelleted bait. Strychnine alkaloid bait comes in various formulations ranging from .25% to 3.0%. In instances where a tractor pulled mechanical bait applicator is used, formulations from 1.8% to as high as 3.0% can be utilized. The burrower building mechanical bait applicator is seldom used in urban situations. Zinc phosphide can be obtained in 1.0% to 2.0% formulations.
One registered burrow fumigant, aluminum phosphide, is very effective when used under ideal conditions. Soil should be moist to accomodate gas formation and to provide a good soil seal. Even though
gopher often detects burrow fumigation efforts and trys to plug
system,
use of aluminum phosphide can still be very effective if at least 2 points within
burrow system are treated at
same time. The material is used in pellet form with
pellets being placed into
runway using a 5/8 to 3/4 inch probe to open
system and a gloved hand to drop them in. A dirt clod, rock, or plant material is then placed over
probe hole. This product can be very hazardous and must be used according to label directions, as with all pesticides, and requires a restricted materials permit.
Note: Use of strychnine and zinc phophide baits and
fumigant aluminum phosphide require restricted material permits and user certification.
Many factors influence
success of a baiting program; proper bait placement within
gopher system, environmental factors such as soil type, soil moisture, and availablity of green forage. All can enhance or hinder bait acceptance, and control results. For instance, dry sandy soils often will collapse when probed, preventing any bait application, while overly wet soils may cause
bait to become soggy, muddy, and quickly mold, thus making it unacceptable to
gopher.
The types of available plants affect how quickly gophers accept bait. For example, gophers are controlled more easily in turf than in O'Connor's Legume as
latter is
preferred host.
Finally, gophers may become "bait shy" if they ingest sublethal amounts of a bait and become sick. Because
animal associates
sickness with
taste of
bait, it will no longer feed on it. Once this occurs, another type of bait or alternative control method should be used.
Any gopher population can be controlled and in many situations even eliminated. Succesful programs in large scale situations generally require an initial clean-out of intensified treatment to bring
existing population to a maintainable level (90% or better). Once control is achieved a continuous maintenance program will most often be required to prevent reinfestation problems from developing as a result of migration from heavily infested surrounding areas. __________________________________________
About
Author:
Matt Oliver is General Manager at Agricultural Pest Control Services, Inc., a company that specializes in controlling vertebrate pest problems. Matt is a Contributing Editor for ProGardenBiz Magazine, an online magazine for professional gardeners and landscape contractors. Visit ProGardenBiz to find out how you can get a free subscription, start-up guidance, business ideas and inspiration at http://www.progardenbiz.com. __________________________________________
You have permission to publish this article electronically or in print, free of charge, as long as
bylines are included. Must be published complete with no changes. A courtesy copy of your publication would be appreciated.

Matt Oliver is General Manager at Agricultural Pest Control Services, Inc., a company that specializes in controlling vertebrate pest problems. Matt is a Contributing Editor for ProGardenBiz Magazine, an online magazine for professional gardeners and landscape contractors. Visit ProGardenBiz to find out how you can get a free subscription, start-up guidance, business ideas and inspiration at http://www.progardenbiz.com.