Fumigation | Belding's ground squirrel
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Fumigation is generally most effective in mid-Spring, but only after Belding's ground squirrels emerge from their burrows and when soil moisture is adequate.
Several fumigants/devices can be used for ground squirrel management. Jump to: |
Aluminum Phosphide
Aluminum phosphide has been shown to be an effective material for controlling Belding’s ground squirrels under the right conditions and can be considerably cheaper than other fumigation management options. However, past studies show rates of effectiveness ranging from 30% to 98% control. It is unknown why control rates vary so greatly. It may be due to local soil or weather conditions. Aluminum phosphide tablets need moisture to create phosphine gas, which is inhaled by the ground squirrels and then enters the bloodstream. Thus, in the absence of adequate soil moisture, the material is not as effective. Dry and/or porous soils are also problematic because they cannot contain the phosphine gas, allowing it to escape from porous, rocky, or cracked soil.
Aluminum phosphide products have the added benefit of controlling flea populations associated with Belding's ground squirrels and their burrow systems.
Restrictions
Aluminum phosphide is a highly restricted use material and requires a restricted use permit to purchase and use. You must also be a certified applicator or be supervised by a certified applicator to use this material.
The use of aluminum phosphide is heavily influenced by location and proximity to people and domestic animals:
Aluminum phosphide products have the added benefit of controlling flea populations associated with Belding's ground squirrels and their burrow systems.
Restrictions
Aluminum phosphide is a highly restricted use material and requires a restricted use permit to purchase and use. You must also be a certified applicator or be supervised by a certified applicator to use this material.
The use of aluminum phosphide is heavily influenced by location and proximity to people and domestic animals:
Aluminum Phosphide use is permitted ONLY when: |
Aluminum Phosphide is PROHIBITED: |
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All permitting and reporting is similar to that required for other federally restricted pesticides with the added requirement of a fumigation management plan. This plan must be written by any applicators who intend to use aluminum phosphide, in accordance with the label instructions outlining the content of the plan. It describes the steps necessary to carrying out a safe and effective management plan.
Application
Always follow the directions on the label to ensure the safety of the applicator.
For application, place 2-4 tablets or 10–20 pellets as far into the burrow as possible. The burrow must be sealed with crumbled-up newspaper, or a similar material, and then covered with soil. This prevents the gas released from escaping through the burrow entrance. Because it is difficult to tell which burrow openings are connected to others, all active burrow openings should be treated and sealed. Only treat active burrow systems, as other species may use abandoned burrow systems. Approximately 48 hours after the initial treatment, the treatment area should be checked for open burrows. Any reopened burrows should be treated again.
Aluminum phosphide products cannot be applied while it is actively raining or snowing, or when there is snow on the ground or if the soil is very wet. Never pour water down the burrow system before or after aluminum phosphide application, as these tablets may spontaneously combust when they come into direct contact with water. The soil in the burrow must be sufficiently moist without the addition of extra water. Soil that is not moist enough to evolve toxic levels of phosphine gas will also be too dry to hold the toxic gases within the burrow system. To determine if the soil is moist enough for effective application, dig down to the level of the burrow system, grab a handful of loose soil, and ball it up in your hand. If the soil holds its shape, it is moist enough for application; if the ball falls apart, the soil is too dry for the application to be effective.
Application
Always follow the directions on the label to ensure the safety of the applicator.
For application, place 2-4 tablets or 10–20 pellets as far into the burrow as possible. The burrow must be sealed with crumbled-up newspaper, or a similar material, and then covered with soil. This prevents the gas released from escaping through the burrow entrance. Because it is difficult to tell which burrow openings are connected to others, all active burrow openings should be treated and sealed. Only treat active burrow systems, as other species may use abandoned burrow systems. Approximately 48 hours after the initial treatment, the treatment area should be checked for open burrows. Any reopened burrows should be treated again.
Aluminum phosphide products cannot be applied while it is actively raining or snowing, or when there is snow on the ground or if the soil is very wet. Never pour water down the burrow system before or after aluminum phosphide application, as these tablets may spontaneously combust when they come into direct contact with water. The soil in the burrow must be sufficiently moist without the addition of extra water. Soil that is not moist enough to evolve toxic levels of phosphine gas will also be too dry to hold the toxic gases within the burrow system. To determine if the soil is moist enough for effective application, dig down to the level of the burrow system, grab a handful of loose soil, and ball it up in your hand. If the soil holds its shape, it is moist enough for application; if the ball falls apart, the soil is too dry for the application to be effective.
Gas Catridges
Fumigation using gas cartridges has shown to be 60% to 100% effective for Belding’s ground squirrel management. Total costs, including labor for gas cartridges are~$3.00/burrow opening vs. ~$1.00/burrow opening for aluminum phosphide. However, gas cartridges are not a restricted use material and can be used without a certified applicator’s license (unlike aluminum phosphide).
The active ingredients of gas cartridges are sodium nitrate and charcoal; some also contain sulphur. This creates carbon monoxide ( and sulphur dioxide if the cartridge contains sulphur) when ignited. This toxic gas displaces oxygen in the animals’ bloodstream and results in death by asphyxiation. Gas cartridges can flare up and cause fire hazards in vegetation, so caution must be taken when using them, particularly in dry conditions to avoid wildfires and injuries to applicators.
Gas cartridges cannot be used to control ground squirrels in or under buildings. Gas cartridges require application beyond a prescribed distance from a structure. This distance varies across products. Please consult all pesticide labels for restrictions before considering their use.
Application
Instructions for the use of gas cartridges may be product specific. It is very important to consult the label for use. Generally to use a gas cartridge, puncture the cartridge cap end at marked points with a nail or other sharp instrument. Insert a fuse into the hole created by the nail. Place the cartridge into an active burrow entrance with the fuse pointing towards the interior of the burrow. Light the fuse and push the cartridge down into an active burrow with a shovel handle. Immediately seal and tightly pack the burrow opening with soil. Multiple entrances to the same burrow system do not necessarily need to be treated separately, but it is important that any additional openings be sealed. Use the smoke escaping from the burrow to find the connected openings. This can lower the increased cost of gas cartridge applications since fewer burrow openings may need to be treated. Larger burrow systems, however, may require two or more cartridges.
As with all other burrow fumigants, be sure that soil moisture is adequate to ensure maximum effectiveness. Approximately 48 hours after the initial treatment, check the treatment area for open burrows; any reopened burrows should be treated again.
The active ingredients of gas cartridges are sodium nitrate and charcoal; some also contain sulphur. This creates carbon monoxide ( and sulphur dioxide if the cartridge contains sulphur) when ignited. This toxic gas displaces oxygen in the animals’ bloodstream and results in death by asphyxiation. Gas cartridges can flare up and cause fire hazards in vegetation, so caution must be taken when using them, particularly in dry conditions to avoid wildfires and injuries to applicators.
Gas cartridges cannot be used to control ground squirrels in or under buildings. Gas cartridges require application beyond a prescribed distance from a structure. This distance varies across products. Please consult all pesticide labels for restrictions before considering their use.
Application
Instructions for the use of gas cartridges may be product specific. It is very important to consult the label for use. Generally to use a gas cartridge, puncture the cartridge cap end at marked points with a nail or other sharp instrument. Insert a fuse into the hole created by the nail. Place the cartridge into an active burrow entrance with the fuse pointing towards the interior of the burrow. Light the fuse and push the cartridge down into an active burrow with a shovel handle. Immediately seal and tightly pack the burrow opening with soil. Multiple entrances to the same burrow system do not necessarily need to be treated separately, but it is important that any additional openings be sealed. Use the smoke escaping from the burrow to find the connected openings. This can lower the increased cost of gas cartridge applications since fewer burrow openings may need to be treated. Larger burrow systems, however, may require two or more cartridges.
As with all other burrow fumigants, be sure that soil moisture is adequate to ensure maximum effectiveness. Approximately 48 hours after the initial treatment, check the treatment area for open burrows; any reopened burrows should be treated again.
Carbon Monoxide
Several carbon monoxide-based devices are currently available for use. The most extensively tested of these devices is the Pressurized Exhaust Rodent Controller (PERC). The PERC machine proved effective for Belding’s ground squirrel (76% efficacy) in moderately moist to moist soil conditions. The PERC machine uses a small engine to create exhaust rich in carbon monoxide, which is cooled and stored in a compressor tank before it is injected into the burrow system. Application times vary depending on the size of the burrow system, but take approximately 3 minutes per burrow. Multiple burrow systems can be treated at once with this device when multiple operators are using it, thereby substantially increasing the speed with which an area can be treated.