Breeding for Pierce’s Disease Resistance Has Sped Up

Traditional Breeding Helps Find Resistance to PD

By Patrick Cavanaugh, Farm News Director

The glassy-winged sharpshooter is a major vector of Pierce’s Disease, which kills grape vines. Pierce’s Disease devastated the grape industry in southern California and lead to the creation of the Pierce’s Disease/Glassy-Winged Sharpshooter Board (PD/GWSS Board). Government programs to fund research on glassy-winged sharpshooters and Pierce’s Disease invest nearly $20 million annually.

California Ag Today recently spoke with Ken Freeze, the outreach and education director for PD/GWSS. He told us about two major methods of control and prevention that the board is funding.

“There’s the area-wide control program, which does everything it possibly can to pretty much keep the glassy-winged sharpshooter confined to basically the southern part of the state,” Freeze said.

This control program prevents the further spread of Pierce’s Disease into other parts of the state, which could devastate wine growers. In addition to preventing the further spread of Pierce’s Disease, the board is also funding additional research into hopefully finding a cure.

“We’ve got UC Davis Genetics Professor Andy Walker working on Pierce’s Disease resistant grapevine before the program, and he just released some of those vines to the UC Davis Foundation Plants Services.”

Freeze said this development has been done through traditional breeding, with the assistance of some new technology.

Walker’s traditional breeding is sped up by a lot of high tech tools. Previously growers would crossbreed, however they’d have to infect the vine and see if it got Pierce’s Disease.

“That could take a year or two. Now they know the genetic markers, so when the plant has only two or three leaves on it, researchers pull a leaf, do a DNA track on it, and look for that marker,” Freeze explained. “Depending on the marker, the vine either goes to the next step in breeding or it ends up in the trash heap. So that has just sped up that process incredibly.”

“Again, that’s all just using traditional breeding,” Freeze said.

California Ag Today2021-05-12T11:05:15-07:00December 4th, 2017|

Pierce’s Disease Research Advancing

Many Projects Under Way To Reduce Pierce’s Disease in Grapes

By Patrick Cavanaugh, Farm News Director

The glassy-winged sharpshooter vectors Pierce’s Disease, which has been devastating grape growers in California for the last few years. California Ag Today recently spoke with Ken Freeze, the Outreach and Education Director for the Pierce’s Disease/Glassy-Winged Sharpshooter Board, a program that uses winegrower’s assessments to fund research. He spoke with us about research that’s been carried out to hopefully find a cure for Pierce’s Disease.

Pierce’s Disease is caused by a bacterium, Xylella fastidiosa, that reduces the vascular function of the vine. The sharpshooter insect vectors the bacteria.

“Andy Walker, with the Department of Viticulture and Enology, UC Davis, has been working on Pierce’s Disease-resistant grapevines. We just released some of those vines to the Foundation Plant Services at UC Davis,” Freeze said. “There are 14 more that are in the wings about ready to go. Some nurseries will be able to get that pretty soon, but already there are about 4,000 of his vines planted. Some of them have been planted in Georgia and Texas, which are real hotspot for the glassy-winged sharpshooter and Pierce’s Disease.”

“Here in California, 2,000 vines were planted in Napa Valley right along the Napa River. Those vines are doing great,” Freeze said.

“We’ve got another project. University of Florida plant pathologist Dr. Don Hopkins has found a benign stain of Pierce’s Disease. It’s like inoculating a vine with a smallpox vaccination. That’s actually a company that’s working on commercializing that now,” Freeze explained.

“We’ve got another project that involves a modified root stalk that sends either a protein or a molecule up into the vine – a non-modified scion – five different ways that stops the Xylella fastidiosa bacteria literally in its tracks before it can cause Pierce’s Disease in the vine. That’s just a small sample of some of the really good projects.”

“One grower told me: ‘It’s not the end of the tunnel, but we can see it,’” Freeze said.

California Ag Today2021-05-12T11:05:15-07:00December 1st, 2017|

Paraquat Resistance in Weeds?

Weeds Now Showing Paraquat Resistance

By Patrick Cavanaugh, Farm News Director

There’s been weed resistance to glyphosate herbicide, but now some weeds show resistance to paraquat herbicide.

“When we see paraquat resistance at often a very high level of resistance, it doesn’t cause any visual injury, which is different than a lot of cases,” said Brad Hanson, a UC Cooperative Extension Weed Specialist at UC Davis.

“We’re dealing with a lot of glyphosate resistant weeds right now, and when you spay glyphosate on the resistant weeds, they are slightly injured and then they recover,” said Hanson. “With paraquat resistance, it’s very stark. You often don’t see any symptoms at all. I describe it almost as immunity. It’s such a high level of resistance.”

“We have glyphosate resistance to annual ryegrass and hairy fleabane, and we have some populations of those same weeds that are resistant to paraquat,” Hanson said. “We see a very temporary reduction in the photosynthetic ability, but within a few hours it bounces back to normal.”

The plant is taking that active herbicide molecule, and it is being sequestered. It’s taking that molecule and putting it somewhere in the cell where it cannot get to the photosynthetic apparatus that’s its target site. It’s a very unique and interesting kind of resistance challenge.

“I think we’re talking about multiple resistance to paraquat and glyphosate. The grower likely switched to use paraquat in order to kill the glyphosate resistant weeds, and then the weeds selected paraquat resistance on top of that.”

Patrick Cavanaugh2021-05-12T11:05:42-07:00March 6th, 2017|

Record Enrollment at UC Davis College of Agriculture and Environmental Sciences

UC Davis College of Agriculture and Environmental Sciences Really Rocks!

By Patrick Cavanaugh, Farm News Director

Helene Dillard, dean, UC Davis College of Agriculture and Environmental Sciences, is pleased with the big numbers of students attending the top-ranking College of Agricultural and Environmental Sciences.

Helene Dillard, dean, UC Davis College of Agriculture and Environmental Sciences

“It’s really rocking,” said Dillard. “We’re doing very, very well. We have one of the largest numbers of incoming students ever in the entire university. Our College has peaked out its 7,300 undergraduates. We’ve never had that many at one time.”

Why the increased interest in studying agriculture? Dillard said, “We think what’s moving that needle is that everyone is interested in food. They are interested in agriculture. And they are really interested in that intersection between agriculture and the environment. We have a record number of students that just cannot wait to come on board. We are really thrilled with how smart they are and how eager they are to learn.”

Among the many courses offered by the College, Dillard said Animal Science classes are probably among the most popular. “But of course, beer classes and the coffee class are really popular too. But right now, I’m seeing tremendous interest in agricultural economics and in animal science, to become veterinarians and ranchers, plus specific academic interest in poultry and sheep.”

“Again, those are all things that UC Davis does, so we’re really excited. We’re also seeing a lot of interest in plant sciences, more on that sustainable and food systems and our viticulture and enology program’s growing as well.

Recent Graduate Program Rankings for UC Davis College of Agriculture and Environmental Sciences and related disciplines include:

1st in agricultural sciences (Thomson Reuters ScienceWatch 2011)
2nd in agriculture and forestry (QS World University Rankings 2016)
2nd in agriculture worldwide (U.S. News & World Report’s “2016 Best Global Universities”)
1st in ecology and the environment (Thomson Reuters ScienceWatch 2011)
1st in food science and nutrition (Thomson Reuters ScienceWatch 2010)
1st in plant science (U.S. News & World Report’s “2016 Best Global Universities”)
1st in animal science (U.S. News & World Report’s “2016 Best Global Universities”)
1st for veterinary science (QS World University Rankings 2016)
1st among the nation’s veterinary schools (U.S. News & World Report’s “Best Graduate Schools” 2016)
Between 1st and 15th among 44 programs in nutritional biology (National Research Council 2010)
4th in environment/ecology (U.S. News & World Report’s “2016 Best Global Universities”)
Between 1st and 7th in Entomology among 28 programs (National Research Council 2010)
Between 5th and 29th among 116 programs in plant biology (National Research Council 2010)
Between 7th and 42th among 116 programs in plant pathology (National Research Council 2010)
13th in environmental engineering worldwide (QS World University Rankings 2016)
29th in environmental engineering worldwide (2016 Global Ranking of Academic Subjects, ShanghaiRankings)

(Source: Universit