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Registered Alternatives to Strychnine to Control Richardson's Ground Squirrels Non-chemical methods Hawks Here is an interesting article about one rancher's method of controlling gophers by constructing nesting platforms for hawks. Exit® Recently registered as a fumigant, it is essentially a concentrate soap-based foaming agent that asphyxiates rodents when introduced in the burrow system under low volumetric pressure through an aerated hand held wand. It contains no toxic chemical and therefore is safe for residential/urban areas but can also be used on agricultural lands. Check out their website at www.exitholdings.com or call toll free 1-800-483-3948 for further information about this product and associated equipment. The closest custom applicator of this product is Dan Mynio of AMF Rodent Control. His phone number is 403-969-7771. The County has an application unit for rent and stocks the EXIT product. Chemical methods Fumigants One type is pyrotechnic fumigants that require combustion to produce carbon monoxide. They are marketed under several trade names such as ‘Giant Destroyer’ ® ‘Woodchuck Bomb®’ ‘Gas Cartridge®’ and most are available at farm or commercial retailers. The other is Phostoxin. One tablet is placed down each burrow and then the burrow is covered. The tablet reacts with moisture in the air and releases toxic phosphine gas. This product was just registered for western Canada in March of 2005. You can read the label at PMRA's website for more details. Producers must be trained in the application of aluminum phosphide to purchase and use this product. This means completing the Olds College Farmer Pesticide Certificate Course. Contact the County Agricultural Fieldman for more details as local courses can be arranged. Zinc phosphide 2% Marketed under the registered name Burrow Oat Bait (BOB), this product was originally registered to control pocket gophers and is formulated on a slightly rolled, kiln-dried oat groat. The purpose of heating the grain is so it will readily absorb the active ingredient exposed to it under high pressure (as opposed to affixing it to the exterior of the substrate). It is believed this process acts to extend the field life of bait, prevent the active ingredient from washing or flaking off, is less odorous (zinc phosphide smells strongly of garlic) and prevents the grain from sprouting. The down side to the bait is that it has not proven to be effective in controlling ground squirrels. Last summer, Saskatchewan Environment Resource Management conducted field trials on Richardson Ground Squirrels that showed unsatisfactory control with BOB. In the U.S. zinc phosphide is the only acute toxicant registered for ground squirrel control and, although it is claimed to be reasonably effective, this is probably because pre-baiting (conditioning ground squirrels by applying untreated oat groats 7-10 days prior to) is required for effective results. Rozol 0.07% (chlorophacinone) (available in 250mL bottles or in 20L pails) This product is an anti-coagulant and is marketed in a liquid concentrate form and is prepared directly by mixing with fresh grain. Rozol is also formulated in an Ready To Use bait but is not as popular as the concentrate. Considered relatively safe compared to acute rodenticides such as strychnine and Zinc Phosphide, Rozol takes a much longer time to reduce rodent numbers because of the long latency period of the anti-coagulant. While the product is considered relatively safe (registered for urban use), cheap and easy to use, its downside is that it takes more than one treatment application to be effective and requires an extended time period of up to several weeks to produce effective results. Although it has produced very good results in Alberta in a single application, field trials conducted in 2002 did not bear this out. However, 2003 field research indicates excellent potential as an effective, affordable and environmentally safe product to use for ground squirrels when a unique flavour enhancer (Edmonton Exterminators) has been added. AAFRD will likely continue further trials this year. In the U.S., studies have shown that although Rozol will reduce ground squirrel populations, operationally it is not considered an effective control agent for ground squirrels. Diphacinone .005% Another anti-coagulant, similar to Rozol, this product was originally registered as a bait for pocket gophers. In paraffinized block, meal grain form only and designed for long term use ( ie underground in pocket gopher burrows), it is unlikely the "Ramik Green" or "Eaton's Answer" will perform very well on ground squirrels because of the bait substrate. It has not been field tested in Alberta, and results of tests conducted elsewhere are not known. Please note: Alternate control agents such as anhydrous ammonia, propane and other inflammables/explosives are not registered in Canada and therefore illegal to sell/use commercially. For your information, research conducted in the U.S. indicate these devices have not proven to be effective in reducing ground squirrel numbers and pose imminent danger to users and bystanders. CHEMICAL INFORMATION SUPPLIED BY: Vertebrate Pest Specialist Alberta Agriculture Food & Rural Development |