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Arizona Cooperative Extension Home
: Counties: Yavapai County Home: Horticulture: Pocket Gopher Pages |
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 Experimental Gopher Control Device 
Introduction This experimental gopher control device uses a small fan to distribute the fumigant throughout connected burrow systems. The device appears to work quite well in preliminary testing year. The device was shared with me through Master Gardener Vic Heinz of Cottonwood, Arizona. He had used this device previously in California. The device can be made from readily available materials and is easy to construct. Depending on where the gopher population is located, the fan can either be powered by 110 volt AC (common household current) or 12 volt DC (car or tractor battery). Experimental Fumigant Rather than using standard gas cartridges, Vic recommended using highway safety flares (fusees). I was able find Orion brand 15 minute flairs for $1.29 each at a local auto parts store. After reading the Material Safety data Sheet on the Orion web site, I learned that the flares produce sulfur oxides, nitrogen oxides, and carbon monoxide. The smoke generated is definitely heavier than air. Once ignited, these flares are also a serious fire hazard and proper precautions should be taken before use. 
Materials List 1 - 5 gallon plastic bucket 1 - 3 inch electric "pancake" type fan (120V AC or 12V DC) 4 - machine screws, washers, and nuts to attach fan to bucket Tools List sabre saw (for hole in bucket) drill (for screw holes) screwdriver Fumigant several highway safety flares Assembly Instructions Place the plastic bucket upside down on the ground with the fan on the center of the bottom of the bucket. Trace the outline of the circular portion of the fan. the screw holes, and the circular opening of the fan onto the bucket. Using a sabre saw (or sharp knife), cut only the circular hole where the air passes through. Mark and drill holes to attach the fan. Use machine screws to attach the fan to the bucket making sure the air blows into the bucket when the power is on.  How to Use the DeviceBefore igniting the fusee, have a power source ready (extension cord or 12V battery). Using a probe to find a main tunnel, excavate and expose the burrow. Shape or level the opening so that the base of the bucket can be sealed with soil. Start the fan, ignite the fusee, place the bucket over the hole, and seal with soil. You should see gray smoke hovering close to the ground as it emerges from nearby mounds. Note which mounds are smoking to get an idea of the extent of the burrow system. Avoid breathing the smoke while lighting and covering.  Since no conclusive scientific data is available for this device, guidelines for use are vague at best. At this time, I would recommend burning at least one fusee per 1,000 square feet of soil surface. If multiple mounds are active within this area, then more fusees should be used. This is similar to the approach used when using wire traps. After the fusee has burned out, allow the residue to cool and remove it from the hole, then replace the soil or sod and level the ground. Monitoring Effectiveness of Control After control efforts are completed for the day, knock down all remaining gopher mounds in the area. This will allow you to detect any new activity that occurs. If new mounds reappear, then repeat treatments as needed. As in any pest control effort, monitoring is critical and repeat treatments may be necessary. Experiment One 
I tested this device at my home during August of 2000. Here, I had gophers eating the root systems of young fruit trees growing in very rocky soil. The difficulties here two fold: 1) not disturbing the young trees root systems, and 2) finding gopher burrows among rocks in the soil (traps are very hard to use under these conditions). After two treatments with this device, no new gopher mounds were seen for the remainder of the growing season. There was no noticeable decline in growth of the trees due to smoke contacting the gopher damaged roots. In addition, no evidence of gophers has been noted five months following treatment. Experiment TwoThe device was also tested on the lawn at the Prescott, Arizona Cooperative Extension Office where gophers appeared to be eating roots of Siberian elm. The gopher(s) present were very active pushing up a new mound every other day. After deploying the device, smoke was first noticed rising from a mound 34 feet away. Shortly thereafter, smoke was coming from a burrow 62 feet away (see photo to the left). A second deployment was done near what appeared to be a separate burrow system 30 feet away, but smoke immediately began to rise from the first deployment area. Four days later, no new activity was seen. Discussion These preliminary data show that this device may have great potential for controlling pocket gophers. However, I have no conclusive data to prove that gophers have actually been killed. They may simply have been repelled by the smoke and residue (the fusee leaves a whitish film on soil surface inside the burrow). I strongly suspect that the smoke residue will deter further occupation by pocket gophers for a limited period of time. More data needs to be gathered and tests need to be conducted under varying conditions to validate this gopher control method. Other Issues Aside from the effectiveness of this device at controlling gophers, I have three additional questions that need further exploration. These are: 1) does the smoke or residue left in the burrow harm plant roots, 2) is this method of gopher control somewhat humane, and 3) will this device have detrimental effects on non-target organisms. Feedback I encourage interested readers to build one of these devices and would welcome any input or suggestion that readers could share. Please respond with comments, questions, and additional information by E-mail: jschalau@ag.arizona.edu The University of Arizona - College of Agriculture and Life Sciences, in Tucson, Arizona. |
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