UC Nursery and Floriculture Alliance
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UC Nursery and Floriculture Alliance

From the UC Blogosphere...

Who's the Boss of the Lavender?

A Valley carpenter bee and a honey bee sharing the same lavender stem. (Photo by Kathy Keatley Garvey)

Some folks refer to them as "those big, black scary bumble bees." They're not bumble bees. They're not scary. But well,...

Posted on Tuesday, May 31, 2016 at 4:25 PM

Drone technology on display at UC research center

A drone takes a test run over a field at the UC Kearney Research and Extension Center.
The UC Desert Research and Extension Center hosted a workshop for employees and local stakeholders on potential uses for drone technology in agriculture, reported Edwin Delgado in the Imperial Valley Press

“The intent of this workshop is to start bringing the knowledge about unmanned aerial systems to the University of California Agricultural and Natural Resources division and the public at large,” said Sean Hogan, coordinator of Informatics Geographic Information Systems for UC ANR. “There is so much curiosity about it right now, it's a growing industry and there is a lot of concern and controversy about the misuses on it.”

The article said the UC system now has the green light to begin using drones. Hogan is holding workshops throughout the state to share his expertise with UC ANR employees and members of the community.

Desert Research and Extension Center director Jairo Diaz said the workshop was important because participants were able to see a demonstration of how the technology works and how it can be applied to the projects and research they are currently working on.

“These workshops that give growers and stakeholders can use in the area are very important because tech like this can help in the near future help find out different types of issues on the field like management of nutrients, water and find out to improve management of field,” Diaz said.

At the UC Kearney Agricultural Research and Extension Center last week, technicians tested a drone that will be used throughout the summer to collect growth data on 600 varieties of sorghum begin produced under different irrigation regimens. With imaging and lidar, the drone collects information on leaf area and biomass in half an hour that would take a full day for a person in the field. 

Read more about the sorghum research at Kearney here.

Posted on Tuesday, May 31, 2016 at 1:38 PM

UC Davis Zika Symposium: A Crucial Message

Chemical ecologist Walter Leal, coordinator of the Zika Public Awareness Symposium, addresses the crowd. (Photo by Kathy Keatley Garvey)

The seven speakers who addressed the UC Davis Zika Public Awareness Symposium on Thursday, May 26 in Giedt Hall, UC Davis...

Posted on Monday, May 30, 2016 at 5:28 PM

Citrus Disease

 

Yellowing Citrus Leaves

Leslie E. Stevens   UCCE Master Gardener

 

Bright green leaves sheltering colorful hanging fruit distinguish healthy citrus trees.  Yellow leaves, on the other hand, spell trouble. 

Causes are numerous, but often relate to improper irrigation and nutrient deficiencies.  Other culprits include pests, bacteria, fungi and phytotoxicity caused by a variety of herbicides, fungicides and salt burn.

Water:  As evergreens, citrus may require irrigation year-round to ensure good soil moisture to a depth of about 2 feet for mature trees.  Conditions that are too wet or too dry can reduce the tree's ability to take up nutrients, especially nitrogen.  Very dry root zones, an impact of the ongoing drought, have led to more nitrogen deficiencies seen in citrus.  At the same time, it's important to ensure good drainage, since water-logged roots cannot adequately absorb soil nutrients.  If you see a tree canopy of pale green-to-yellow leaves, check your soil moisture in the top two feet before applying fertilizers.

Allow the top 6 inches of soil to dry between watering, typically ranging from 7-to-14 days depending on weather and soil conditions.  For this reason, citrus trees should not be planted in lawns or near heavily irrigated plants.  Also ensure you have good soil moisture on the deep end of the rootzone so that roots can take up available nutrients.

Fertilizer:  Citrus trees require regular doses of nitrogen, zinc, manganese, magnesium and iron to remain healthy and productive.  Two or three applications of a slow-release citrus formula annually should do the trick.  If you only manage a single dose per year, apply in early spring prior to flowering and fruit setting when nutrient demand is highest.

Mulches: A nutrient-rich mulch of yard waste consisting of wood chips, grass clippings and leaves can also be beneficial for citrus trees, according to the University of California.  The high nitrogen in grass clippings offsets the high carbon of the wood chips, and the combination has been shown to be effective in suppressing Phytophthora root rot when present in the soil. 

Also be sure to keep mulches at least 6 inches from tree trunks to discourage fungi and bacterial growth on trunk and roots.

Resources:  Visit UC- IPM Website for colored pictures and detailed descriptions of common diseases and deficiencies negatively affecting citrus trees.

http://www.ipm.ucdavis.edu/PMG/C107/m107bpleaftwigdis.html  

 

 

 

 

Posted on Monday, May 30, 2016 at 10:36 AM

Annual Bluegrass Lawn Weed

Advice from the Help Desk of the
UC Master Gardeners Program of Contra Costa

Client:  This weed is growing in my lawn. Could you please tell me what it is and how do I eradicate and/or prevent it?

MGCC Help Desk:  Thank you for bringing the weed sample from your lawn for identification and recommendations on its elimination and control.

Annual Bluegrass
We have been able to identify this sample as Annual Bluegrass (Poa annua), a very common lawn weed in coastal areas of California. This annual weed looks similar to regular lawn grass for a short while. It also looks a little like Kentucky bluegrass, except it has a lighter shade of green, shallower roots, and develops a short seed head early in the season. It dies off when the weather gets hot, leaving big empty patches in your lawn

Annual bluegrass loves damp, shady areas. You can reduce favorable conditions for this weed by watering deeply and infrequently. The weed's shallow roots will not be able to reach down to where the moisture is. Annual Bluegrass will also invade lawns where the soil has become compacted. You can reduce lawn compaction by aerating during non-sprouting periods. This will allow water to settle deeper in the soil away from the shallow-rooted weeds.

Annual Bluegrass Leaf Tip
Annual Bluegrass typically grows in dense, low clumps, 3 to 12 inches (8–30 cm) tall. To reduce its ability to survive in your lawn, mow your grass high, preferably between 3-4 inches to shade out the weed. Lawns with taller grass tend to have fewer Annual Bluegrass problems. Mowing high will also reduce the opportunity for flowering. Annual bluegrass reproduces by seed and can have many generations in a single season if left to flower and set seed.

For more information on this weed and its control, please see the UC Davis publication, How to Manage Pests in Gardens and Landscapes - Annual Bluegrass at http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7464.html.

Please let us know if you have any additional questions

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


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, May 30, 2016 at 12:18 AM

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