Chlorophacinone 0.01%, Diphacinone 0.01%, and Zinc Phosphide 2.0%
ATV driver using spotter to keep a straight course.
BEST MANAGEMENT PRACTICES
Time of Year:
- Late spring and early summer is the best. The appropriate time for baiting is related to vegetation more than calendar dates. In portions of central and northern California, the 6-week period from May 15-June is often the best treatment period. The optimum treatment period would occur earlier in southern California. After the optimum period, estivation is likely. However, in unusual years with late spring rains and cool temperatures such as in 1998, the "window" for treatment can be pushed back considerably.
Ideal vegetation conditions: brown and dried out - When herbaceous vegetation should be brown and dried out. Green vegetation upon which ground squirrels are feeding should not be present. This time usually corresponds to the time when young squirrels emerge from their burrows
- Do not bait during hot periods when estivation is likely or is occurring.
- Do not bait if a storm is due within 48 hours
- Apply bait in the morning if possible.
- If broadcasting in agricultural fields, it must be done when food or feed crops are not growing.
Reduce Materials:
- Conduct a bait acceptance test. This will tell you whether or not the squirrels have switched to a seed and grain diet and whether or not they will likely take the poison bait. If you just put out the bait and they are still eating green vegetation or don't like the bait, you risk wasting all of the bait and the time you spent putting it out.
- Prebait with clean grain 2-3 days before distributing the poison bait
- Do not over bait. Use only the amount specified on the label. Increasing the amount of bait does not increase efficacy. Be sure to calibrate equipment so the proper application rate is used.
- Apply bait only through infested areas. Fifteen feet on either side of the burrow should be sufficient.
Non-Target Species:
Kangaroo rat in unmodified bait station.
- Local county ag commissioners can give advice on how to avoid impacting non-target species. If kangaroo rats or other non-target species are at risk, use anticoagulants in modified bait stations (Box or PVC). For more information, see the website for the DPR Endangered Species Project .
- Do not have bait available in areas accessible by farm/ranch animals, domestic animals, or children.
- Do not graze animals in treated areas
Safety:
- Do not touch bait with bare hands. Gloves, respirators and eye protection must be worn when broadcasting.
- Keep poison bait out of reach of children, pets, and other animals. Be sure to lock it up when not in use.
- Clean up and dispose of all spilled bait or bait that was put out but not consumed.
- Mechanical spreaders used for poison bait should not be used for anything else.
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Other Considerations:
- Depending on your needs, there are a variety of spreaders you may choose to use. An easy way to broadcast this bait is to use handheld rotary spreader available at your local hardware store.
- You can also try a push rotary spreader, but the width that it distributes the bait is very narrow and is not recommended.
- Handheld rotary spreaders are available at your local hardware store for between $9 and $25.
Directions for use (check and follow label instructions):
1. Conduct a bait acceptance test.
2. Calibrate equipment. Calibration is extremely important to be sure that the correct amount of bait is being distributed. Too little may render it ineffective, and too much will be a waste of materials and is a violation of the label
3. Prebait with the same type of grain used for poison baiting 2-3 days prior to bait application. (Zinc Phosphide only)
4. Bait in the morning.
5. Apply bait at the rate specified on the label. The label recommendation may be a little misleading. The label might recommend the application rate of 10 lbs./acre through infested areas. If you have 1 acre, you might assume you need 10 lbs. of bait. However, the rodenticide should be applied only to burrow areas or other places where squirrels are feeding. On many control sites, only 10-15% of the actual area needs to be treated. Therefore, a label rate of 10 lbs./acre would mean only 1 to 1.5 punds of bait is actually applied.
Chlorophacinone and Diphacinone --Apply at a rate of 10 lbs. per swath acre through infested areas. Repeat application in 2-3 days.
Zinc Phosphide --Apply at a rate of 6-10 lbs. per swath acre through infested area. (For rangeland apply at a rate of 6 lbs. per swath acre.) Do not apply more than once per year to the same treatment area.
6. In areas that are used for food or feed, apply to the ground so the bait does not come in contact with the crop; or apply only during the dormant season. Do not graze animals on treated areas.
7. If possible, collect dead carcasses daily and dispose of properly.