San Luis Obispo County
University of California
San Luis Obispo County

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Ground Squirrels Thrive Year-Round in Avocado Orchards

Ground squirrels eat a variety of fresh greens as well as seeds and dried nuts. In spring, ground squirrels prefer greens over seeds and nuts.  Once the natural grasses begin to dry and wither, squirrels will actively forage for seeds. 

As foragers, squirrels are well-adapted to find sparsely dispersed food, one seed at a time. Once squirrels have had their fill, they will

collect food in their cheek pouches and take it back to the nest to form a cache for later use. Squirrels tend to forage close to their burrow, although they will travel for desirable foods.

How Biology relates to control:

The California ground squirrel prefers to forage for food in the early morning or late afternoon/early evening to avoid the day's heat. In some crop situations, especially nut crops, squirrels may prefer the crop to the point where they will not eat any bait. If the squirrel won't eat the bait, the poison bait method will not work. In this case, an alternative control approach may be necessary (trapping or fumigation).

Understanding these feeding preferences is extremely important when using baits since they are seed based. Also, in irrigated crops or landscape areas, squirrel feeding preferences are influenced by what food is available. For example, the natural vegetation may be dry in early summer and squirrels are actively foraging for seed. If newly sprouted crops are available however, the squirrels may take them with great delight.

The calendar of ground squirrel diet, activity and control measures is adapted from the Best Management Practices for Ground Squirrel Control website  Calendar dates are merely an estimation of time; actual time frames may vary according to the weather and location. 

Ground squirrels - Spenrophilus sp. of which there are 17 species may cause damage to avocado orchards by eating fruit, branches, and making burrows near or under trees which expose roots and redirect irrigation water. The most common ground squirrel is the California or Beechey ground squirrel Spermophilus beecheyi.

*An adult will weigh from 1 to 2 ½ pounds and is tan in color with flecked or mottled fur.

*Females produce one litter each year, averaging six to eight offspring.

*They are active in the daytime.

*Their diet may consist of green herbage in winter and spring and seeds during the summer and fall.

*They hibernate during cold winters, but are active year-round in avocado growing areas

*Ground squirrels are not repelled by any chemical or physical means. Thus, control through the use of toxic fumigants, poison baits, traps, or shooting is the only effective control measures available

*They are also preyed on by eagles, raccoons, foxes, badgers, weasels, rattlesnakes and clever dogs

more on those cute animals:


ground squirrel
ground squirrel

Posted on Monday, December 10, 2018 at 7:36 AM

Get that Tubing Right

While conducting surveys across Merced County, I have noticed diverse ways growers secure the ends of irrigation tubing.  Many are attached using some type of stake made of wood or PVC in which the tubing is tied. Other orchards have the lines wrapped around a tree and used as an anchor for the line. Finally, some of them are staked directly into the ground. 

Irrigation tubing moves because of expansion and contraction of the plastic caused by temperature changes, as well as, from the water and air moving through the irrigation system. Securing the tubing creates tension that helps prevent the tubing from moving. These keeps the emitters and microsprinkers in place which helps maintain good irrigation efficiency.

There are a few problems with securing the tubes. The first is the added cost and time to first secure the tubing and then maintain how the tubing was secured. Secondly, the lines may contract after fixing, which can pull them off the riser. Finally, the lines, if wrapped too tight, can cut into and girdle the tree. All of these are preventable.

If you do choose to secure the end of your irrigation tubing, below are some considerations to take into account:

  • Leave some slack in the tubing: Due to changes in temperature, plastic tubing expands and contracts. When tightly secured tubing contracts, coupling points may become undone (e.g., at the riser) or may cause the plastic in the tubing to stretch, creating weak points that may eventually break.
  • Be wary of using trees to secure tubing: While this may cut down on supply costs, make sure it does not begin to girdle the tree.
  • Do it right: Since you are taking the time (and money) to secure your tubing, be sure to do it right. There is a lot of power in the contraction and expansion of irrigation tubing, and a poorly installed system will eventually fail.
  • Secure irrigation tubing in the winter: Securing tubing on colder days prevents problems related to contraction. Cold tubing that does not have enough slack will just expand and create the slack that was needed. Hot tubing that does not have enough slack will contract and cause problems, as described above
  • .

Whether or not you decide to secure your irrigation tubing is up to you. Ultimately, the end goal is a well-irrigated field. Securing irrigation tubing, if done right, is just one thing to help accomplish that goal.

From the Almond Doctor:



Posted on Friday, December 7, 2018 at 6:42 AM
  • Author: Cameron Zuber

Citrus Forum

The University of California Cooperative Extension office in Tulare County, is launching a new website to facilitate exchange of information among individuals involved in citrus production in California, from growers to academics.

The ideology within this forum is to allow people within the field to exchange information in real time. It has been my personal observation, for example, that many PCA's have their own small network of individuals that they rely on for information regarding specific issues or problems encountered in the field and often only talk amongst themselves.  It is my belief that having an internet-based forum would allow individuals to broaden this ‘in house group' to all individuals involved in the industry to better communicate ideas, information, and concerns regarding various aspects of citrus production. The forum site is set up to deal with the various citrus regions; SJV, Desert, Coastal, Southern Interior, and Sacramento Valley. The specific areas set up thus far are; Pests, Diseases, Irrigation, Fertility, Weeds, Harvesting Issues, and Post-Harvest Issues.  Two additional sections have also been set up for discussions: a general citrus area, and a posting area dealing with all issues related to ACP/HLB.  Users will also be able to upload pictures taken from the field when posting a question.

The utility of this forum is that a person has the ability to make an observation in the field, snap a couple of pictures of what he/she sees, and easily post this information to the forum where the citrus community at large could view and respond to start a thread on the topic. This could be done out in the field using a smart phone or tablet or from an office computer at the user's leisure. The success of this network will rely on individuals in the citrus industry to utilize this new important tool. The site is up and running but is certainly in the beta-testing phase. Therefore, having individuals using the site and reporting any problems or making suggestions on making it better is highly desirable. If the forum is successful, support will be sought to produce an app for cellular phones to make the process easier than a web-based forum. For further information or ideas of how this site can be improved, please contact Greg W. Douhan, SJV Citrus Advisor, UCCE, Tulare, California:

Get on the forum at:

citrus forum
citrus forum

Posted on Wednesday, December 5, 2018 at 6:16 AM
  • Author: Greg Douhan

Which Way HLB - Huanglongbing and Asian Citrus Psyllid? Now in Marin.

The best way to delay arrival of HLB in our area and minimize its impact is to keep ACP suppressed down to the lowest level possible.  By treating in coordination with neighbors in an areawide approach, grower ACP treatments can have a greater impact on ACP populations than treating independently and out of sync with neighbors. Best Management Practices, such as making sure all equipment arriving and leaving your grove is free of citrus stems and leaves, can also greatly reduce the risk of HLB-positive psyllids entering your grove.

CITRUS REMOVAL PROGRAM: Citrus trees that are neglected or abandoned may harbor ACP and HLB, increasing risk to other citrus in the area. Abandoned and neglected trees may be reported to Cressida Silvers at 805-284-3310,  or the county Ag Commissioner's office. The Citrus Matters ACT NOW program may be able to assist in citrus removal. For more information contact Joel Reyes at or (559) 592-3790. 

Asian Citrus Psyllid / ACP

There have been no ACP detections in San Luis Obispo County since our last update.

Huanglongbing / HLB

The most recent map and totals for HLB detections are posted at the website As of November 16, the total number of trees that have tested positive for the HLB bacterium is 948, still all in LA, Orange, and Riverside Counties. All HLB detections have been on residential properties and the infected trees have been or are being removed. No HLB has been found in commercial groves to date.

Clarification on Field Cleaning Requirements for Movement of Bulk Citrus

To clarify the approved mitigation measures for bulk citrus fruit movement, the California Department of Food and Agriculture (CDFA) has updated the Asian Citrus Psyllid (ACP)-Free Declaration form. The current options that allow growers to meet the ACP-free standard when shipping fruit to a different ACP regional quarantine zone are the “spray and harvest,” “field cleaning with machine” and “wet wash” methods. Field cleaning must be done by machine, not by hand.

To read the full article, click here:

Upcoming CPDPC Meetings

  • Joint Science and Technology Subcommittee and Regulatory Task Force meeting Thur., December 6 at 1:30 pm in Sacramento. Agenda attached, including link to join by webinar/phone.
  • CPDPC Operations Subcommittee meets Wed., December 12 at 9 am in Visalia. Agenda attached with link to join by webinar/phone.
  • The next meeting of the CPDPC Full Committee will be January 9 in Visalia. Agenda is pending. 
  • All meeting agendas and eventually the minutes are posted at . All meetings are free and open to the public, and accessible via webinar.  

Additional Resources


And Now it's in Marin County

SACRAMENTO — Marin County has been placed under quarantine for the Asian citrus psyllid (ACP) following the detection of one ACP in the City of Novato. The entire county is included in the quarantine zone.

The ACP is an invasive species of concern because it can carry the disease huanglongbing (HLB), also known as citrus greening.  All citrus and closely related species, such as curry leaf trees, are susceptible hosts for both the insect and disease.  There is no cure once the tree becomes infected. A diseased tree will decline in health and produce bitter, misshaped fruit until it dies.  In California, HLB has been detected at residential properties in Los Angeles, Orange and Riverside counties. This plant disease does not affect human health.

Residents with backyard citrus trees in the quarantine area are asked not to transport or send citrus fruit or leaves, potted citrus trees, or curry leaves from the quarantine area. For commercial citrus, the quarantine prohibits the movement of citrus and curry leaf tree nursery stock, including all plant parts except fruit, out of the quarantine area. The quarantine also requires that all commercial citrus fruit be cleaned of leaves and stems prior to moving out of the quarantine area.  An exception may be made for nursery stock and budwood grown in USDA-approved structures that are designed to keep ACP and other insects out.

ACP quarantines are in place in Alameda, Contra Costa, Fresno, Kern, Kings, Madera, Merced, Monterey, Placer, San Benito, San Joaquin, San Luis Obispo, San Mateo, Santa Clara, Solano, Stanislaus, Tulare, Yolo, Imperial, Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara, and Ventura counties, as well as Marin.

Residents in the area who think they may have seen ACP or symptoms of HLB on their trees are urged to call CDFA's Pest Hotline at 1-800-491-1899 or a local agricultural commissioner's office  For more information on the ACP and HLB, please visit: Residents are also asked to follow these steps:

  • Inspect trees for the Asian citrus psyllid and Huanglongbing monthly, and whenever watering, spraying, pruning or tending trees. Psyllids are most noticeable when new leaves are growing on the tips of the branches.
  • As part of your tree care, visit your local nursery or garden center to get advice on products that can help protect your citrus tree.
  • Do not move citrus plants, foliage or fruit into or out of your area, and especially across state or international borders. This could unknowingly contribute to spread of the pest and disease.
  • When planting a new citrus tree, be sure to get your tree from a reputable, licensed nursery in your local area.
  • When grafting citrus trees, only use registered budwood that comes with source documentation, such as the budwood offered through the Citrus Clonal Protection Program.
  • Be sure to dry out citrus tree clippings or double bag them before removing the plant material from the property.

–California Department of Food and Agriculture

ACP adult and nymph
ACP adult and nymph

Posted on Friday, November 30, 2018 at 11:00 AM

Great Citrus Tasting!!!!

Date: December 15, 2018

Time: 9:00 AM - 12:00 PM

Contact: Jasmin Del Toro: 559-592-2408 ext 1151

Sponsor: Lindcove Research and Extension Center

LocationLindcove Research and Extension Center

Event Details

The general public is invited to join us for a family friendly Citrus Tasting Event. You can see and taste more than 100 citrus varieties that are grown at Lindcove Research and Extension Center. Take a bag of fruit home for $10. Choose from Cara Caras, Navels, Mandarins, or assorted citrus from 4 bins located in front of the Conference Center. The Master Gardeners as well as UC Cooperative Extension Advisors will be happy to answer questions from home gardeners and citrus connoisseurs.

Directions: Take Highway198 east to Mehrten Drive (approximately 15 miles) and follow the signs to our Event. The University of Lindcove Research and Extension Center is located at 22963 Carson Avenue Exeter, CA. The Conference Center is located at the end of Carson Avenue. If you have any questions please contact Jasmin Del Toro at 559-592-2408 Ext 1151 or

 Lindcove Fruit Display Tasting-home owners 2018

lindcove fruit tasting
lindcove fruit tasting

Posted on Friday, November 30, 2018 at 7:33 AM

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