Soil Health & Cover Crop Field Day

There's a new pub in town, and you can read it up.  It's a generic guide to mulch use.

Mulches for Landscapes

Mulches are materials that are applied to the soil surface, but not tilled, mixed, or combined with underlying soil. Landscape mulches are typically plant residues (organic mulches) or rock, sand, and stone (inorganic mulches). You may know that immediately after application mulches prevent weeds from germinating and reduce evaporative loss from soil surfaces, but there are other benefits as well.  And down sides, as well. 

Includes a table of common mulch materials with their benefits and potential problems.

This free publication is available by download.

Read more.  Know more.  And there's a lot more to read at ANR Publications.

By Tina Hilding, Voiland College of Engineering and Architecture

https://news.wsu.edu/2019/09/11/researchers-grow-citrus-disease-bacteria-lab/

PULLMAN, Wash. – Washington State University researchers have for the first time grown the bacteria in a laboratory that causes Citrus Greening Disease, considered the world's most harmful citrus disease.

Being able to grow the elusive and poorly understood bacterium, Candidatus Liberibacter asiaticus (CLas), will make it easier for researchers to find treatments for the disease that has destroyed millions of acres of orange, grapefruit and lemon groves around the world and has devastated the citrus industry in Florida.

The researchers, including Phuc Ha, postdoctoral research associate, Haluk Beyenal, Paul Hohenschuh Professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering, David Gang and Ruifeng He, from WSU's Institute of Biological Chemistry, Anders Omsland, from the Paul G. Allen School for Global Animal Health, and researchers from the University of Florida and University of Arizona, report on their work in the journal, Biofilm.

WSU was selected three years ago for a $2 million U.S. Department of Agriculture grant to study the bacteria, in part, because Washington has no citrus industry. The disease, formally known as Huánglóngbìng, (HLB), is spread by Asian citrus psyllids insects. It attacks the vascular system of citrus trees and causes fruit to become green, misshapen, and bitter-tasting.

A critical step in coming up with weapons to fight the disease is being able to study it in the lab, but the CLas bacterium is notoriously difficult to grow. With a small genome, CLas is thought to depend on very specific nutrient availability and possibly compounds secreted by other nearby bacteria. When researchers used a traditional rich media that they typically use for growing bacteria, they mostly grew bacteria other than CLas.

So, in order to conduct research, scientists have had to get bacterial samples directly from the trees themselves or from the insects that spread it, which is time-consuming and cumbersome. Trying to conduct experiments has also been difficult because, unlike neat lab cultures, bacterial samples gathered from a sick tree vary, depending on where and when the sample is gathered and the level of infection.

Without being able to grow the bacteria in a lab, researchers have been unable to even absolutely confirm that the bacteria, in fact, causes the disease.

In their paper, the researchers for the first time successfully established and maintained CLas bacterial cultures outside of its host.

Using infected citrus tissue as their starting point, the researchers developed a biofilm, a kind of bacterial city that allows a variety of bacteria to thrive. Instead of a rich growth medium that would crowd out the CLas, the researchers severely limited the growth of partner bacteria and created a medium with the specific nutrients, acidity, incubation temperatures, and oxygen levels that are optimal for CLas.

The CLas thrived – an important first step.

“We were really excited,” said Beyenal, “but then we wondered if we could re-grow it.”

The researchers were able to transfer the orange-colored culture and grow new cultures in their biofilm reactors, which they have maintained for more than two years.

“We can do this for as long as we want,” said Beyenal.

Beyenal's group is now working to purify the culture, which will further help researchers to study it.  They are also developing genetic-based methods to understand and mitigate the spread of the disease.

Media contacts:

• Haluk Beyenal, Hohenschuh Distinguished Professor, Gene and Linda Voiland School of Chemical Engineering and Bioengineering, 509-335-6607, beyenal@wsu.edu.
• David Gang, Professor, Institute of Biological Chemistry, 509-335-0550, gangd@wsu.edu
• Tina Hilding, communications director, Voiland College of Engineering and Architecture, 509-335-5095, thilding@wsu.edu

Photo: Phuc Ha and Haluk Beyenal examine a bacterial culture in the laboratory. 

The California Avocado Society held its 104^th Annual Meeting recently and acknowledged an individual's contributions to the avocado industry with its Oliver Atkins Award. This award is presented in honor of nurseryman Oliver Atkins who went beyond what was required or expected, benefitting the avocado industry and its growers. His devotion to the industry was noted in his day-to-day activities and to the changes that he brought to the industry. The award was made to Mr. Pablo Rodriguez.

The award was presented by Nurseryman Rob Brokaw and the following notes were made during the address:

Pablo Rodriguez was born in Mexico in 1950, one of eight kids. He attended a private school on scholarship from ages 8-12, finishing his formal education at 8^th grade. He came to the US in order to support his parents and siblings at age 20 in 1971 and worked up and down California for two years before landing at an avocado/citrus nursery in Ventura county.

The nurseryman at the time made a point of “keeping an eye on Pablo”, and Pablo soon rose to be the nursery manger, developing an expertise in grafting. He bought a home in Santa Paula, raising a family there. He gained US citizenship in 1996. He and his family also have a company that performs topworking which is now managed by son Robert.

Readying a rootstock for a graft

As the nursery became involved in working with partners overseas, Pablo's expertise was in demand. He has worked with collaborators in Mexico, Peru, and Dominican Republic, Chile, Florida, Hawaii, Spain, South Africa and more.

His skills and expertise are evident in the millions of avocado and citrus trees that have been produced here in California under his watchful eye, but the greater impact of his efforts resonates around the world.

Pablo and Samuel Garibay showing South Africans the Brokaw Way

Today Pablo is in semi-retirement. In his case, that means he works just as much as he ever did. He's constantly operating in the background shoring up processes and ensuring smooth operations. On Sundays, he can be found wandering the orchards – “just making sure the graftwood is good for harvest this week!” He isn't asked to do this; he just does it because it needs to be done.

But the real story about Pablo, apart from his intelligence and his accomplishments, is his profound humility and humanity. Pablo's dealings with others are informed by a deep spirituality and morality. He seeks to raise others, preferring to remain in the shadows.

Pablo is a guy who, when asked if he can do the impossible, will think for a while, then shrug and say, “Well, it has to be done”. And then does it. This happens regularly.

To his family, to California growers and to the global avocado industry, Pablo has given selflessly of himself. We're all enriched by his presence in our community.

A Serious budman

2019 Date Palm Field Day

November 21, 2019

8:30 - 2:15 PM

Coachella Valley Agricultural Research Station

86501 72nd Ave, Thermal, CA 92274

Fee: $25, lunch included

Agenda

8:00am – Registration for CE units, coffee, pastries

8:30am- Welcome- Sonia Rios, UCCE Riverside

8:45am- Tom Perring, UC Riverside. Current status of Insect and Mite Pests of dates

9:15am- Tom Perring, UC Riverside. Part 1: What we know about puffy skin of medjool dates

9:30am- Robert Krueger, USDA/ARS. Part 2: What we know about puffy skin of medjool dates/Date research pollination update

9:45- Ali Montazar, UCCE. An update on the on-going irrigation management project in California date palm

10:15am-Break

10:35- Mark Hoddle, UCR. Updates on the South American Palm Weevil Invasion

11:35- MaryLou Polek, USDA/ARS. Update on Date Palm Activities at the Repository

12:05pm- Lunch- Sponsored by Corteva 

1:15pm- Peggy Mauk, UC Riverside.

1:45 - Bob Mulherin, Riverside Agriculture Commission. Laws and Regulation Updates

2:15 – Wrap up

Space is Limited-Register online at:

http://ucanr.edu/survey/survey.cfm?surveynumber=28232

*No Cash/Check payment will be excepted on site, day of

DPR/ISA Continuing Education Credits Upon Request