- Author: Carolyn Whitesell
- Author: Niamh Quinn
- Posted by: Elaine Lander
Regardless of what type of management option you use, you must first consider whether there are endangered or threatened species present on the property that may use ground squirrel burrows (such as burrowing owls, tiger salamanders, etc.). To check if there are endangered species on your property and to learn about proper uses of pest management products when these species are present, you can consult the PRESCRIBE tool. Trapping may still be an option if there are endangered species present, as long as you use and properly set specific trap designs, ensuring that they are inaccessible to endangered species. After determining whether endangered or threatened species need to be considered, you need to think through the pros and cons of each method, as explained below.
Toxic Baits
There are two categories of toxic baits available for California ground squirrel control: first generation anticoagulant rodenticides (FGARs, which require multiple feedings) and zinc phosphide (an acute toxin that may only require a single feeding). Many toxic baits are restricted use pesticides. Anyone applying a restricted material must hold a pesticide applicator's license and will need a restricted use material permit. A notice of intent must be given to your county ag commissioner's department at least 24 hours before the application of a restricted use material. Applicators then have up to four days after the planned date (the date on the notice of intent) to begin the application; otherwise, a new notice of intent must be filed. A written recommendation from a Pest Control Advisor may also be required. If you have any questions about what permits or paperwork are required for using a particular rodenticide, check with your local Agricultural Commissioner's office.
In general, when applying any type of rodenticide, always read the label carefully. The label will specify how to apply the bait correctly, the timing of subsequent applications (if applicable), the target species for which the toxic bait can be used, and the locations permitted for use. You must always have a copy of the label with you on site when you apply rodenticides.
FGARs can be used as spot treatments, broadcast applications (though not for resident use), or in bait stations. There is an antidote (Vitamin K1) available for the active ingredients in FGARs, but, since it is not 100% effective and requires a prescription from a veterinarian, these products should not be applied if you have any concerns that nontarget animals will be able to access the bait. There is a primary risk of nontarget exposure from the use of FGARs, however it is generally necessary for it to be consumed over multiple days, on multiple occasions to achieve a toxic dose.
Zinc phosphide does not have an antidote available and can only be used as a spot treatment or a broadcast application (NO bait stations). It is not permitted for use in or around buildings, and the label is species-specific for many locations, so always double check the label before applying it. You must be a licensed pesticide applicator to use this toxic bait to manage California ground squirrels. It poses a higher primary toxicity risk (due to direct consumption) but a lower secondary toxicity risk (due to consumption of a poisoned animal) to nontarget animals than the FGARs.
When using toxic baits, you should check for and properly dispose of squirrel carcasses daily. Always wear gloves when handling carcasses.
Trapping
For multi-catch live traps, which allow you to catch multiple ground squirrels at once, it is very important to pre-bait. That means you should place bait within the trap for a few days without setting the trap and allow the ground squirrels to feed on the bait freely. Pre-baiting will get the older and potentially trap-shy ground squirrels more comfortable with the trap and will increase your odds of catching them once the traps are set. When doing any sort of trapping, you are ideally looking to catch the adults, not just the younger, typically less wary, individuals. If you are able to catch a mature individual, its alarm calls will act as a form of bait in and of itself and will attract other ground squirrels into the trap.
To avoid contacting squirrel urine or feces, wear gloves when handling any type of trap, even if the trap is empty. You are required by the California Department of Fish and Wildlife to check the traps at least once daily.
Traps must be set more than 150 yards from any structure used as a permanent or temporary residence, unless such traps are set by a person controlling such property or by a person who has and is carrying written consent of the landowner to place the trap or traps.
California ground squirrels, once trapped, must be immediately killed or released in the site where trapped. Unless released, trapped animals shall be euthanized following AMVA guidelines or by shooting where local ordinances, landowners, and safety permit.
For more detailed information on ground squirrel control and other control methods not mentioned here, check out ANR's online resources Pest Notes: Ground Squirrel and the Ground Squirrel BMPs website.
[Article originally published in the Summer 2021 issue of the Green Bulletin.]
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- Author: Cheryl Reynolds
We're pleased to announce that a new online course on managing ground squirrels and pocket gophers has been added to UC IPM's growing library of online training courses. This course consists of eight video segments recorded by Dr. Roger Baldwin, a University of California Cooperative Extension Specialist in Human-Wildlife Conflict Resolution. Originally presented in June of 2020 as part of the UC Ag Experts Talk webinar series, the course covers pest identification, types of damage they cause, and the importance of their biology and ecology.
If you are a pest management professional or grower interested in vertebrate pest management, then check out this course! You'll learn about current control strategies such as habitat modification, baiting options, fumigation, and trapping. The course content is free to anyone who wishes to view it. For those requiring a certificate of completion and continuing education units (CEUs), the regular cost is $20, but we are offering a reduced price of $10 through October 31, 2021. To receive the discount, enter the code SquirrelGopher50 in the voucher box when making the payment. Managing Ground Squirrels and Pocket Gophers has been approved by the California Department of Pesticide Regulation (DPR) for 1 CEU in the Other category and also by Certified Crop Advisor (CCA) for 0.5 unit of IPM credit.
If you are a DPR license or certificate holder with a last name beginning with letters M through Z, then this will be your year to renew. Now is a good time to check out the other UC IPM online training courses offered. All are 50% off the regular price through October 31st.DPR will be sending out renewal packets in August and strongly suggests returning them by October so that your license or certificate can be renewed before it expires.
UC IPM not only offers courses accredited by DPR, but many courses are also approved by the California Structural Pest Control Board (SPCB), Certified Crop Advisor (CCA), the Western Chapter of the International Society of Arboriculture (WCISA), and the Arizona Department of Agriculture.
- Author: Elaine Lander
Annually on February 2, groundhogs get a lot of coverage. Groundhogs, also known as woodchucks, are burrowing rodents often found in the eastern United States. But in California, any shadows from burrowing rodents are unlikely to be a groundhog. Here in the Golden State, you will find other types of burrowing rodents including pocket gophers, ground squirrels, voles, and Norway rats. Though not rodents, moles are another burrowing animal that you may encounter in gardens and landscapes.
See the following UC IPM Pest Notes to learn more about these burrowing vertebrate pests.
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- Author: Belinda J. Messenger-Sikes
We took a look at which titles were of greatest interest during the first five months of the COVID-19 pandemic when many Californians were staying home. These are the top ten most viewed Pest Notes from March to August 2020.
#10 Pocket Gophers
Got gophers? You can control these pesky rodents with traps. See our videos for instructions on how to find gopher tunnels, where to place gopher traps, and how to set Macabee and Gophinator traps.
Get more details at Pest Notes: Pocket Gophers.
#9 Whiteflies
Signs of a whitefly infestation can include:
- Tiny nymphs on the underside of leaves.
- Sticky honeydew on leaves, fruit, or beneath plants, or a covering of black sooty mold.
- Yellowing, silvering, or drying leaves that have whitefly nymphs on them.
- Deposits of white wax (with certain whiteflies).
For more information and management tips, see Pest Notes: Whiteflies.
#8 Scales
What does scale damage look like?
Damage resembles that of aphids and whiteflies. There is abundant sticky honeydew (excreted by soft scales and certain other species). Black sooty mold may be growing on the honeydew. Discolored, distorted, or dying leaves, twigs, or branches (especially with armored scales) may be present.
Need to know more? See Pest Notes: Scales.
#7 Carpet Beetles
How did carpet beetles get in my house?
- Carpet beetle adults are pollen feeders and are found on flowers with abundant pollen like crape myrtle, spiraea, and buckwheat.
- People often bring carpet beetles into their homes on cut flowers from the garden.
- Adults can fly in through open windows or doors without screens.
If you think you've got carpet beetles and need to know how to get rid of them safely and effectively, read Pest Notes: Carpet Beetles.
#6 Ground Squirrels
Ground squirrels cause damage by, eating food-bearing and ornamental plants, gnawing on plastic sprinklers and irrigation lines, girdling young trees, and burrowing, which causes trip hazards and damages landscapes and structures.
Learn more at Pest Notes: Ground Squirrel.
#5 Thrips
You often won't see damage until tissue grows and expands. Look for:
- Scabby, silvery to dark brown discoloration on fruit, leaves, or petals
- Dark specks of excrement on fruit or leaves
- Distorted, curled, galled, or dead shoot tips and leaves
Thrips are difficult to control. You'll need to combine methods for best results. For more information, see Pest Notes: Thrips.
#4 Mealybugs
What do mealybugs look like?
Most adult mealybugs are wingless females with oval, segmented bodies covered with wax. Males have wings but are rarely seen. Newly hatched mealybug immatures move around plants but soon settle down and produce a waxy covering. Different mealybug species can be distinguished by the length of the waxy filaments around their bodies. They may be confused with other insects that produce wax and honeydew like cottony cushion scale, woolly aphids, soft scales, and whiteflies. Mealybugs are sometimes hard to see. They often live in protected areas of plants such as in the crown of a plant, in branch crotches, or on stems near the soil.
Mealybugs suck sap, weakening plants. High populations can slow plant growth and cause leaf drop. For help managing mealybugs, read Pest Notes: Mealybugs.
#3 Aphids
How can you reduce aphids?
- Prune infested leaves and stems.
- Knock aphid populations off plants by shaking the plant or spraying it with a strong stream of water.
- Protect seedlings with covers or aluminum foil mulches.
- Wait for hot weather; some aphids are heat-intolerant and will be gone by mid-summer.
Still have questions? Find out more about aphids in Pest Notes: Aphids.
#2 Fungus Gnats
What can you do about fungus gnats?
Avoid overwatering and provide good drainage. Allow the surface of container soil to dry between waterings. Clean up standing water, and eliminate any plumbing or irrigation system leaks. Avoid using incompletely-composted organic matter in potting media unless it is pasteurized first, because it will often be infested with fungus gnats. Screen and caulk leaky windows and doors to help prevent pests like fungus gnats from coming indoors.
For more management tips, read Pest Notes: Fungus Gnats.
#1 Peach Leaf Curl
How do you effectively manage peach leaf curl?
- The fungal spores that cause the disease spend the winter on twigs and buds and germinate in the spring.
- For effective control, treat trees just after leaves have fallen, usually late November or December.
- Consider a second application in late winter before buds swell, especially in areas with high rainfall or during wet winters.
- Don't apply fungicides during the growing season because they won't be effective.
For more information see Pest Notes: Peach Leaf Curl.
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- Author: Ben Faber
Learn about vertebrates in the orchard.
And all those other animals
that are attracted to avocado orchards
like ground,squirrels,
coyotes,
birds,
mountain lions,
bobcats and
others
The California Avocado Society,
California Avocado Commission
and University of California Cooperative
Extension have their bimonthly meeting:
June Seminar Topic
Vertebrate Management
(2 hours of DPR CE Approved)
Speakers: Niamh Quinn: Human-Wildlife Interactions Advisor
Dates/Times/Locations:
Tuesday, June 11, 2019, 1:00 p.m. to 3:00 p.m.
UC Cooperative Extension Office Auditorium, 2156 Sierra Way, San Luis Obispo, CA 93401
Wednesday, June 12, 2019, 9:00 a.m. to 11:00 p.m.
UC Cooperative Extension Office Auditorium, 669 County Square Dr., Ventura, CA 93003
Thursday, June 13, 2019, 12:30 p.m. to 2:30 p.m.
Fallbrook Public Utility District Board Rm., 990 East Mission Rd., Fallbrook, CA 92028
No registration is required.