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From the UC Blogosphere...

Helicoptering in on the Spanish Lavender

A honey bee nectaring on Spanish lavender. This was taken with a Nikon D500 and a 200mm macro lens. Settings: ISO 3200, f-stop 13, and shutter speed of 1/640 of a second. No flash. (Photo by Kathy Keatley Garvey)

If you like writing with light (photography), then you'll probably love capturing images of honey bees spinning like...

Posted on Tuesday, March 28, 2017 at 4:49 PM

A Summit to Save the Butterflies

Tora Rocha (left), founder of the Pollinator Posse of Oakland (soon to be statewide), and Mia Monroe, coordinator of the Xerces Society's Western Monarch Thanksgiving Count, address the crowd. (Photo by Kathy Keatley Garvey)

Let's wing it, they said. And they did. But this event wasn't "winged"; it was well planned and rooted in educational...

Posted on Monday, March 27, 2017 at 4:50 PM

Trouble in Citrus Paradise!!

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

California Department of Food and Agriculture (CDFA which also oversees much of CCC's Department of Agriculture) released documents March 21st announcing that Asian Citrus Psyllid (ACP) had been found March 6 in both El Sobrante (centered but includes portions of Richmond and El Cerrito) (https://www.cdfa.ca.gov/plant/pdep/treatment/notices/2017/ACP-NOT-ElSobrante-ContraCosta-March-2017.pdf) and Pleasant Hill (plus portions of surrounding cities) https://www.cdfa.ca.gov/plant/pdep/treatment/notices/2017/ACP-NOT-PleasantHill-ContraCosta-March-2017.pdf). CDFA also announced that with cooperation of the CCC Agriculture Commissioner, they will soon commence with treatment to hopefully eradicate those found and prevent further spread.

Asian Citrus Psyllid
Brownish adult, yellow nymphs, and white wax of the Asian citrus psyllid, Diaphorina citri
ACP is the vector (i.e. pest) that carries and infects citrus with HLB (Huanghlongbing or “greening disease”). There is significant information already available on the web on ACP and HLB by CDFA and UC. HLB is fatal to infected citrus. Despite lots of research on this fatal disease, so far there is no known cure and/or prevention of HLB other than preventing the ACP vector from infesting trees. HLB has decimated Florida citrus (40% reduction last 11 years) and has the potential to do similar damage to California's $2 billion dollar citrus industry. So far, commercial growers in California have seen limited impact with quarantines and ACP prevention, but with maybe 1 in 3 home gardens also growing citrus in California, the potential for ACP migration and infestation and transmittal of HLB to commercial orchards is significant. Long seen elsewhere in citrus growing areas around the world, ACP were originally found about decade ago in Southern California on home garden citrus, most likely brought in from other citrus-growing states. ACP have been steadily working their way north despite quarantines and treatments implemented by CDFA. Until this year CCC wasn't home to known ACP, but ACP were found previously in counties to the east, south, and west of CCC. This year ACP have also been found in Solano county to the north and with the announcements this month have also now been found in El Sobrante and Pleasant Hill. (click on the maps below for larger maps). Are you next?

Click the map images for full page size maps
ACP Map El Sobrante March-2017














ACP Map Pleasant Hill March-2017














With ACP found in CCC and if you are growing citrus in your garden, you are strongly encouraged to check your citrus for ACP presence . Helpful UC IPM web guidance can be found at http://ipm.ucanr.edu/PMG/PESTNOTES/pn74155.html#PSYLLIDVIDEO (with video on how to detect ACP) as well as the CDFA web site (https://www.cdfa.ca.gov/plant/acp/).

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


Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925) 646-6586, 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 Blog  (http://ucanr.edu/blogs/CCMGBlog/). 

Posted on Monday, March 27, 2017 at 12:20 AM

Fire Blight

 

Fire Blight

By Linda Lewis Griffith   UCCE Master Gardener

 

“Why are the blossoms and leaves on my apple tree turning brown?    Deb R.   Arroyo Grande

 

Your tree may be infected with fire blight.

Fire blight is a common and frequently destructive bacterial disease that affects pome fruit trees and other related plants.  Pears and quince trees are highly susceptible.  Apples, crabapples and Pyracantha species can also be susceptible to damage. Fire blight infections may destroy limbs and even entire shrubs or trees.

Fire blight is caused by a bacterium, Erwinia amylovora, that overwinters in cankers on twigs, branches or trunks of host trees.  Warm, daytime temperatures between 75 and 85 degrees interspersed with intermittent rain or hail create ideal conditions for bacteria to thrive.  Splashing rain or insects transmit pathogens to nearby blossoms or succulent new shoots.    

Symptoms first appear in spring as trees begin to grow.  A watery, light tan liquid oozes out of infected areas.  The ooze darkens after exposure to air, leaving streaks on branches and trunks. Cankers may be inconspicuous and go unnoticed until later in spring when flowers, shoots and young fruit shrivel and turn black.

Vigorously growing shoots are the most severely affected; conditions such as high soil fertility and abundant water increase the severity of damage. 

Management begins by first selecting varieties of plants that are less prone to damage. For instance, Fuji, Gala, Golden Delicious, Johnathan, Mutsu, Pink Lady and Yellow Newtown are susceptible to fire blight; Empire, Pristine and Williams Pride are considered more resistant. 

Once infections have taken hold, it is necessary to prune out diseased branches.  Cut infected branches at least 8 to 12 inches below the visible injury or canker.  A greater distance below infections may be required on major branches, scaffolds or trunks in May or June when fire blight bacteria are moving rapidly.

To avoid spreading bacteria during the pruning process, dip or spray pruning tools with a 10 percent solution of bleach (one part bleach to nine parts water) before each cut.  Dry and oil tools after use to prevent rust. 

 

For more information about fire blight, visit these websites:

http://ipm.ucanr.edu/DISEASE/DATABASE/fireblight.html

http://www.ipm.ucdavis.edu/PDF/PESTNOTES/pnfireblight.pdf

https://ucanr.edu/sites/placernevadasmallfarms/files/112366.pdf

Posted on Saturday, March 25, 2017 at 1:10 PM
  • Author: Linda Lewis Griffith
  • Editor: Noni Todd

There's Gold on Them Thar Roses

Matched pair: Two multicolored Asian beetles on rose leaves in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

There's gold on them thar roses. No, not the kind of gold found during the California Gold Rush (1848–1855) that...

Posted on Friday, March 24, 2017 at 4:28 PM

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