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From the UC Blogosphere...

International Pollinator Conference Comes to UC Davis

A longhorned bee flies over a Mexican sunflower blossom (Tithonia) in Vacaville. (Photo by Kathy Keatley Garvey)

It's all about the pollinators--whether they be bumble bees, longhorned bees, squash bees, sweat bees, honey bees or...

A longhorned bee flies over a Mexican sunflower blossom (Tithonia) in Vacaville. (Photo by Kathy Keatley Garvey)
A longhorned bee flies over a Mexican sunflower blossom (Tithonia) in Vacaville. (Photo by Kathy Keatley Garvey)

A longhorned bee flies over a Mexican sunflower blossom (Tithonia) in Vacaville. (Photo by Kathy Keatley Garvey)

A squash bee, a specialist bee that forages on the genus Cucurbita, buzzes out of squash blossom in Vacaville, Calif. (Photo by Kathy Keatley Garvey)
A squash bee, a specialist bee that forages on the genus Cucurbita, buzzes out of squash blossom in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

A squash bee, a specialist bee that forages on the genus Cucurbita, buzzes out of squash blossom in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

A honey bee (Apis mellifera) and a yellow-faced bumble bee (Bombus vosnesenskii) share a flower on the UC Davis campus. (Photo by Kathy Keatley Garvey)
A honey bee (Apis mellifera) and a yellow-faced bumble bee (Bombus vosnesenskii) share a flower on the UC Davis campus. (Photo by Kathy Keatley Garvey)

A honey bee (Apis mellifera) and a yellow-faced bumble bee (Bombus vosnesenskii) share a flower on the UC Davis campus. (Photo by Kathy Keatley Garvey)

Posted on Wednesday, July 17, 2019 at 5:55 PM

Male Longhorned Bees: Boys' Night Out!

Male longhorned bees, Melissodes, spending the night on a Mexican sunflower (Tithonia)in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

Boys' Night Out! Have you ever seen a cluster of longhorned male bees sleeping overnight on a Mexican sunflower...

Male longhorned bees, Melissodes, spending the night on a Mexican sunflower (Tithonia)in Vacaville, Calif. (Photo by Kathy Keatley Garvey)
Male longhorned bees, Melissodes, spending the night on a Mexican sunflower (Tithonia)in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

Male longhorned bees, Melissodes, spending the night on a Mexican sunflower (Tithonia)in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

Male longhorned bees, probably Melissodes agilis, begin to wake up after spending the night clustered on a Mexican sunflower (Tithonia) in Vacaville, Calif. (Photo by Kathy Keatley Garvey)
Male longhorned bees, probably Melissodes agilis, begin to wake up after spending the night clustered on a Mexican sunflower (Tithonia) in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

Male longhorned bees, probably Melissodes agilis, begin to wake up after spending the night clustered on a Mexican sunflower (Tithonia) in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

Posted on Tuesday, July 16, 2019 at 6:40 PM

Soils And Water Management

Photo By Tami Reece

    Soils and Water Management By Leonard Cicerello  UCCE Master Gardener   How...

Posted on Tuesday, July 16, 2019 at 9:06 AM
  • Author: Leonard Cicerello
  • Editor: Noni Todd

How This Tiny Warrior Crashed the Hammock Lab Water Balloon Battle

Jasmine Morisseau, 10, holds a male praying mantis, a Stagmomantis limbata, the tiniest warrior at the Bruce Hammock Lab Water Balloon Battle. (Photo by Kathy Keatley Garvey)

He wasn't invited, but he crashed the party anyway. A few minutes before the 16th annual Bruce Hammock Lab Water Balloon...

Jasmine Morisseau, 10, holds a male praying mantis, a Stagmomantis limbata, the tiniest warrior at the Bruce Hammock Lab Water Balloon Battle. (Photo by Kathy Keatley Garvey)
Jasmine Morisseau, 10, holds a male praying mantis, a Stagmomantis limbata, the tiniest warrior at the Bruce Hammock Lab Water Balloon Battle. (Photo by Kathy Keatley Garvey)

Jasmine Morisseau, 10, holds a male praying mantis, a Stagmomantis limbata, the tiniest warrior at the Bruce Hammock Lab Water Balloon Battle. (Photo by Kathy Keatley Garvey)

Filling water balloons for the Bruce Hammock Lab Water Balloon Battle are (from left) Yuan Ding, visiting graduate student; Dongyang Li, assistant project scientist; and Deguang Liu, visiting scholar. (Photo by Kathy Keatley Garvey)
Filling water balloons for the Bruce Hammock Lab Water Balloon Battle are (from left) Yuan Ding, visiting graduate student; Dongyang Li, assistant project scientist; and Deguang Liu, visiting scholar. (Photo by Kathy Keatley Garvey)

Filling water balloons for the Bruce Hammock Lab Water Balloon Battle are (from left) Yuan Ding, visiting graduate student; Dongyang Li, assistant project scientist; and Deguang Liu, visiting scholar. (Photo by Kathy Keatley Garvey)

Some 2000 colorful water balloons are ready to be tossed. In the background is water warrior Lea Barnych, 4, whose mother Natalia Vasylieva is a researcher in the Bruce Hammock lab. (Photo by Kathy Keatley Garvey)
Some 2000 colorful water balloons are ready to be tossed. In the background is water warrior Lea Barnych, 4, whose mother Natalia Vasylieva is a researcher in the Bruce Hammock lab. (Photo by Kathy Keatley Garvey)

Some 2000 colorful water balloons are ready to be tossed. In the background is water warrior Lea Barnych, 4, whose mother Natalia Vasylieva is a researcher in the Bruce Hammock lab. (Photo by Kathy Keatley Garvey)

UC Davis distinguished professor Bruce Hammock catches a water balloon tossed at him. (Photo by Kathy Keatley Garvey)
UC Davis distinguished professor Bruce Hammock catches a water balloon tossed at him. (Photo by Kathy Keatley Garvey)

UC Davis distinguished professor Bruce Hammock catches a water balloon tossed at him. (Photo by Kathy Keatley Garvey)

Splash! It was an international soakfest at the Bruce Hammock Lab Water Balloon Battle, with eight  countries represented. That's Hammock in the center getting sprayed. (Photo by Kathy Keatley Garvey)
Splash! It was an international soakfest at the Bruce Hammock Lab Water Balloon Battle, with eight countries represented. That's Hammock in the center getting sprayed. (Photo by Kathy Keatley Garvey)

Splash! It was an international soakfest at the Bruce Hammock Lab Water Balloon Battle, with eight countries represented. That's Hammock in the center getting sprayed. (Photo by Kathy Keatley Garvey)

Christophe Morisseau, a researcher in the Hammock lab and coordinator of the Bruce Hammock Lab Water Balloon Battle, gets drenched. (Photo by Kathy Keatley Garvey)
Christophe Morisseau, a researcher in the Hammock lab and coordinator of the Bruce Hammock Lab Water Balloon Battle, gets drenched. (Photo by Kathy Keatley Garvey)

Christophe Morisseau, a researcher in the Hammock lab and coordinator of the Bruce Hammock Lab Water Balloon Battle, gets drenched. (Photo by Kathy Keatley Garvey)

Gregory Zebouni, account manager for the Hammock lab, gets drenched. (Photo by Kathy Keatley Garvey)
Gregory Zebouni, account manager for the Hammock lab, gets drenched. (Photo by Kathy Keatley Garvey)

Gregory Zebouni, account manager for the Hammock lab, gets drenched. (Photo by Kathy Keatley Garvey)

The water warriors pose for a group portrait following the 16th annual Bruce Hammock Lab Water Balloon Battle. (Photo by Kathy Keatley Garvey)
The water warriors pose for a group portrait following the 16th annual Bruce Hammock Lab Water Balloon Battle. (Photo by Kathy Keatley Garvey)

The water warriors pose for a group portrait following the 16th annual Bruce Hammock Lab Water Balloon Battle. (Photo by Kathy Keatley Garvey)

Posted on Monday, July 15, 2019 at 3:07 PM

Problems with Oaks

Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County

"Diminishing" Live Oak Tree
HD Client's Request:  I have a very large live oak in my front yard. In recent years I have noticed a decline, wonder if you can help. Please see pictures below. The 2nd picture shows tree within the 10 ft radius from the trunk. Could that have caused problems? Do I need to move them now since the tree is suffering?  City of Lafayette approved my neighbor's drive way, could that have caused the problem? Finally, I had a Certified Arborist come and look them and they suggested a fungal treatment. Is that appropriate?  Can that treatment be done by myself as they charge $500 per year and on going?  I live in mid-County Thank you in advance for your help


Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with your question about your oak tree. First off, let me say that I am sorry about your oak tree. It does not look very healthy in the picture you provided. While it is common for live oaks to shed significant leaves in the spring, it sounds like you are seeing a more general decline over years which is likely due to other causes. I also should note that our advice is based solely on the picture, as opposed to the arborist who come to your house and personally reviewed the tree on-site. Their advice is likely to be more accurate. You mentioned that they want to treat the tree yearly with a fungicide. Did they actually diagnose a fungal disease?

These would be my concerns for your oak based on the information you provided:

You mention that your neighbor's driveway was put in a few years ago. I presume that is the driveway either in front or behind the tree in the pictures. Regardless, both driveways appear to be under the drip line of the tree. The drip line of a tree is the outermost circumference of the leaf canopy. This is where, in rain, water will drip from the leaves of the tree onto the ground. Oak trees are very susceptible to damage from root compaction and grading. Any construction that has occurred under the tree could result in the death of important roots and the subsequent impending death of the tree. The death of the tree under these circumstances may not be fast, it might take years. Below is a link to a graph with an algorithm to determine if your oak tree may have Sudden Oak Death. Notably, it mentions that you need to consider physical damage first. Depending on when this driveway was installed, this may be the most likely cause of the trees decline. http://ipm. ucanr.edu/PMG/PESTNOTES/pni7498-1c.html

  1. It is impossible to tell what kinds of plants were placed under the oak tree. The general rule for planting under oak trees is that plants should be quite a few feet from the trunk and that the understudy plants cannot require summer water. If these plants under the oak tree are being watered regularly, that can make the oak tree more susceptible to fungal diseases from the soil. Mature oak trees should not be watered during the summer at all. You should only water during the winter if there is insufficient rain (less than 20 inches/season).
  2. Lastly a fungal disease would be a possible cause for this kind of decline. There are a variety of fungal diseases that can affect oak trees, however, one of the most concerning is a fungal disease called Phytophthora ramorum. The common name for the disease it causes is Sudden Oak Death. This disease is typically spread from nearby infected California bay laurel trees, rhododendrons or camellias. The pathogen survives on the leaves of the bay laurel and is transmitted to nearby oaks by rain or wind. Once on the oak it infects the trunk and the tree can develop a canker where it bleeds a thick, sticky sap. There is a rapid browning (over 2-4 weeks) of the leaves, however, the tree has usually been infected for two years at that point. This disease is diagnosed by sampling the leaves of nearby host plants (usually a nearby bay laurel) or the bark. Bark sampling should be done by an expert. This disease does not have any cure. There is a fungicide (phosphonate, Agri-Fos) which is approved as a preventative treatment. This will not cure affected trees but will suppress disease progression in early cases. It is injected into the tree or sprayed on the trunk. While it appears you can purchase this product and apply it yourself, it requires special equipment to give the tree injections. You could spray the tree but would likely need special equipment to spray a tree of this size. Given those considerations, treatment is likely a job best left to the arborists. If you treat for fungal disease, and it is not a fungal disease, you may adversely affect the health of the soil under the tree. Fungicides are non-specific and using one may kill non-disease causing fungi that are normal components of soil. For this reason, it is best to get a diagnosis of this disease before starting expensive treatments. There is more information about this disease at the following link.
    http://ipm.ucanr.edu/PMG/PESTNOTES/pn74151.html

I hope this information proves helpful to you as you make decisions about this tree. Below is a link to a very extensive guide to diseases of oak trees which you may want to look through. http://www.suddenoakdeath.org/pdf/psw_gtr197.pdf 

Best of luck with your oak tree. Please contact the Help Desk again if you have more questions.

Help Desk of the UC Master Gardener Program of Contra Costa County (SES)


Note: Contra Costa's Help Desk is available almost year-round to answer your gardening questions.  Except for a few holidays (e.g., last 2 weeks December), we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 2380 Bisso Lane, Concord, CA 94520. We can also be reached via telephone:  (925) 608-6683, email: ccmg@ucanr.edu, or on the web at  http://ccmg.ucanr.edu/Ask_Us/. MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Biog.


Posted on Monday, July 15, 2019 at 12:10 AM

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