Fumigants are toxic gases or vapors that are introduced into the squirrel burrow system. This is a good method of control because it provides quick results and it introduces relatively low levels of toxicity into the environment.

BEST MANAGEMENT PRACTICES FOR FUMIGATION

Time of Year:

• Fumigate in the spring when soil moisture is high or at other times when irrigation provides soil moisture. This prevents fumes from escaping through dry cracks in the soil. 
• Do not fumigate when squirrels are hibernating or estivating because they plug their nesting chamber and fumes will not reach them.
• For most effective control, fumigate 3 weeks after first squirrels emerge from hibernation .
• Re-treat any burrow that has been re-opened after 2 days.

Reduce Materials:

• Squirrel burrows often have several entrances. If the number is high, you can reduce your fummigation effort by dragging the fields or shoveling in the burrow openings to determine which burrows are active. The squirrels will easily dig out, but not from some of the interconnected burrows. Treat only those that are re-opened.
• Use only amount specified on label. Applying more fumigant than recommended to each burrow does not increase efficacy.

Non-Target Species:

• Sometimes other animals, including endangered species , make use of squirrel burrows. You must be especially careful in kit fox, kangaroo rat, burrowing owl, and blunt-nosed leopard lizard areas.

Safety:

• Do not use fumigants near dry grass or other flammable materials. ·
• Do not treat burrows that are in or near buildings. Check label for specific restrictions.

Laws and Regulations :

• Certain fumigants require special permits for use.  See fumigants list for details.

Other Considerations: