- Author: Pat Bailey
The virus is of particular concern to wine grape growers, whose grapes must reach a certain sugar content level before they are suitable for winemaking.
"The most urgent research need now is to determine how the virus spreads," said Deborah Golino, UC Cooperative Extension specialist in the Department of Plant Pathology at UC Davis and director of the UC Davis-based Foundation Plant Services.
"Due to the distribution of the virus in many parts of the United States and evidence that it can be transmitted by grafting, we suspect that red blotch disease is widespread wherever grapes are grown," Golino said.
Golino encouraged vineyard owners and managers to evaluate their vineyards for red blotch disease as they would for any other viruses.
Symptoms include blotches of pink or red veins on green leaves in the fall, when grape leaves would normally be turning a uniform gold color. Growers also might notice that their grapes are slow to develop sugar levels sufficient for winemaking, with some grapes never fully maturing.
"If there are visual signs of red blotch, as well as poor sugar development, growers should test their vines for both red blotch and leafroll virus because the symptoms of the two viruses are so similar," Golino said.
She reported that red blotch disease has been identified among both young and mature grape vineyards in California, New York, Virginia, Maryland, Pennsylvania, Texas and Washington. A virus almost genetically identical to red blotch also was found in Canada.
While the virus, also called grapevine red blotch-associated virus or GRBaV, likely can be found in all types of grapes, including rootstock, and table and raisin grapes, it was first detected in wine grapes because they are carefully monitored for sugar content to determine harvest date.
Presence of the virus in a vine can be confirmed using an extremely sensitive laboratory test known as polymerase chain reaction, or PCR, to detect small amounts of genetic material. This analytical process uses an amplification technique that multiplies the existing DNA and similar genetic material to identify the virus.
"If the vineyard tests positive for red blotch, the grower needs to decide, from an economic standpoint, when is the best time to remove the diseased vines and replant the vineyard," Golino said. "This is always a complex decision, and there is no one-case-fits-all answer."
Golino said that the Foundation Plant Services' Classic Foundation vineyard block, used for producing disease-free scion and rootstock vines, has been partially tested and appears to have a very low-level incidence of red blotch virus. Only three of the 1,600 vines tested to date were found to have the virus. Testing of all of the vines in the Classic Foundation vineyard, the source of the majority of grapevine nursery stock in California, is slated for completion in the months to come.
"The good news is that our new Russell Ranch Foundation Vineyard block has been tested, and there is no sign of red blotch virus in any of those vines," Golino said. This vineyard is propagated exclusively with vines that have been through tissue-culture therapy to exclude red blotch and other viruses. Test records from the Foundation Plant Services vineyards are available at http://fps.ucdavis.edu.
Golino cautioned that many more new viruses and other microbes are likely to be found in grapevines in the next few years, thanks to powerful new DNA sequencing technology.
"Some of those will be disease agents, some beneficial, and some neutral," she said. "We will have our work cut out for us in understanding the role of these microbes, but the ultimate result will be increased ability to create superior vineyards."
"The appearance of red blotch virus underscores the vital importance of the Foundation Plant Services and adequate funding for USDA's National Clean Plant Network," said John Aguirre, president of California Association of Winegrape Growers. "Growers need clean plant material to meet winery demands for increased winegrape production and improved quality."
Golino said that progress on identifying and characterizing red blotch has been a collaborative effort between many university-based researchers over the years.
Red blotch disease was first recognized in 2008 in a Napa Valley vineyard by Jim Wolpert, a UC Davis-based Cooperative Extension viticulturist, and Mike Anderson, a viticulture researcher and manager of UC Davis' Oakville Experiment Station.
Two UC Davis scientists - Mysore Sudarshana , a U.S. Department of Agriculture researcher in the plant pathology department, and Maher Al Rwahnih, a researcher at Foundation Plant Services - teamed up in an effort to identify the virus causing red blotch disease. Al Rwahnih was an early user of next-generation, or high-throughput DNA sequencing technology.
During today's meeting, Golino announced that California rootstock nurserymen acted last week to assist the California viticulture industry with research addressing GRBaV. The California Grape Rootstock Research Foundation, which funds research to enhance California viticulture and the grape nursery industry, has agreed to provide seed money to jumpstart research on the virus.
More information on red blotch disease is available on the University of California Integrated Viticulture website.
Foundation Plant Services is a self-supporting unit of the College of Agricultural and Environmental Sciences at UC Davis. The service, dedicated to the distribution of disease-tested, true-to-identity plant materials produced by UC researchers, plays a key national and international role in distributing new crop varieties and healthy planting stocks.
About UC Davis
For more than 100 years, UC Davis has engaged in teaching, research and public service that matter to California and transform the world.
Located close to the state capital, UC Davis has more than 33,000 students, more than 2,500 faculty and more than 21,000 staff, an annual research budget of nearly $750 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges -- Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science. It also houses six professional schools -- Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing.
Media contacts:
- Deborah Golino, Foundation Plant Services, (530) 754-8102, dagolino@ucdavis.edu
- Pat Bailey, UC Davis News Service, (530) 752-9843, pjbailey@ucdavis.edu
The team found that earthworms do not, as was suspected, stimulate carbon sequestration in the soil, which helps to reduce greenhouse gas emissions. Instead, they actually increase greenhouse gas emissions through a variety of ways.
"There was a hypothesis that earthworms were having a positive effect on the greenhouse balance, but they don't," said co-author Johan Six, a plant sciences professor at UC Davis during the study who is now a professor at ETH Zurich in Switzerland. "I would never say you have to take out the earthworms because of greenhouse gases. It's just that you cannot give them credit for reducing greenhouse gases."
The scientific team was led by Jan Willen van Groenigen of Wageningen University in the Netherlands, and, along with UC Davis, included colleagues from Trinity College Dublin, and the International Center for Tropical Agriculture in Cali, Colombia.
The team gathered all relevant published research to date: 57 different experiments.
The research team then employed a statistical technique called meta-analysis to discern overall patterns in the data.
They found that the presence of earthworms increased nitrous oxide emissions from soil by 42 percent and carbon dioxide emissions from soil by 33 percent. But they found no indications that earthworms affect soil organic carbon stocks -- the carbon stored within the soil.
According to the researchers, earthworms likely increase greenhouse gas emissions several ways: they mix organic plant residues in the soil, which may increase decomposition and carbon dioxide emissions; the earthworm gut acts as a microbial incubator, boosting the activity of nitrous oxide-producing microbes; and the earthworms, by burrowing through the soil, make it easier for greenhouse gases in the soil to escape into the atmosphere.
Small changes in soil greenhouse gas dynamics can have important repercussions for global warming, the researchers said. But lead author Ingrid Lubbers from Wageningen University said it is not yet clear to what extent the effects of earthworms on plant growth may negate earthworm-induced increases in greenhouse gas emissions.
"Our literature search also pointed out a large gap in the published studies," Lubbers said. "We need more experiments that include growing plants, as well as more long-term studies and more field studies before we can decide to what extent global worming leads to global warming."
- Author: Jeannette E. Warnert
FoodCorps was formed when President Obama signed legislation in 2009 to engage AmeriCorps in building a more sustainable, healthful and equitable food system in the United States. FoodCorps trains service members to nurture in youth an enduring relationship with healthy food and sends them to underserved areas, where they educate students about gardening and eating garden-fresh produce.
FoodCorps, which served 12 states last year, adds California, Hawaii and New Jersey in 2013. Pending funding, 12 service members will be placed with 10 organizations in California.
“We are thrilled to have been chosen to host a service member,” said Dorothy Smith, UCCE advisor in the Central Sierra office. “Our service member will build interest and participation in the fruit and vegetable gardens we have in Calaveras County schools. A few schools don’t have a garden, and we’ll get those up and running.”
The new FoodCorps service member will work closely with the UCCE CalFresh youth nutrition education program and the UCCE Master Gardener program. Also, Kevin Hesser, the teacher/garden coordinator for Calaveras Unified School District, will collaborate with the service member.
Smith said UC Cooperative Extension and the Calaveras Unified School District decided to apply for the service member when they realized that the goals of the FoodCorps program closely matched their own efforts to enhance youth nutrition by gardening.
“We want people, and especially kids, to eat whole foods, more fruits and vegetables,” Smith said. “We know that when kids plant broccoli, tend it and pick it, they are much more likely to try it. Once people realize a vine-ripened tomato tastes totally different than the ones they buy from the store, they are more likely to grow their own produce and eat it.”
The FoodCorps program also offers a unique experience to the person chosen for the paid position. Service members are often recent college graduates looking to make a difference in the world while gaining work experience before beginning their careers. UC Cooperative Extension will be involved in selecting the candidate for the local program. Applications are due March 24. Apply on the FoodCorps website.
For more information about the FoodCorps program in Calaveras County, contact Dorothy Smith, (209) 754-6476, dorsmith@ucanr.edu.
- Author: Jeannette E. Warnert
Conceived by Michael Cahn, UCCE farm advisor in Monterey County, and programmed by the UC Agriculture and Natural Resources web team, the free website – ucanr.edu/cropmanage – allows farmers to quickly calculate the precise fertilizer and water needs of their crops.
“It’s great,” said Salvador Montes, ranch manager at Corey Ranch in the Salinas Valley, who pilot-tested the software last year on lettuce crops. “It’s very accurate in predicting the irrigation times and fertilizer (needs). It actually worked! We didn’t see any significant yield reduction using less water and fertilizer.”
By applying only the exact amount of water and fertilizer to optimize plant growth, the new website keeps farmers from using too much. Overfertilizing in the past has resulted in groundwater contamination with nitrate, a serious concern in the Salinas Valley and other farming regions. In coastal areas, overpumping wells can lead to sea water intrusion into the aquifer.
“Besides, fertilizer and water are expensive inputs,” Cahn said. “Applying more than the crop needs is like throwing money down the drain.”
On Feb. 26, Cahn will offer a mini CropManage workshop during the 2013 Irrigation and Nutrient Management Meeting at the Monterey County Agricultural Center, 1432 Abbott Street in Salinas. The meeting runs from 7:45 a.m. and concludes with a pizza lunch at 12 noon. Following lunch, the one-hour CropManage workshop begins. No reservations are required.
“Inspiration for this project,” Cahn said, “came from local growers who expressed a need for software to help them use the quick nitrate soil test and weather-based irrigation scheduling in their farming operations.”
Cahn and his colleagues, Tim Hartz, UCCE specialist in the Department of Plant Sciences at UC Davis, and Richard Smith, UCCE advisor in Monterey County, have been conducting trials for years to determine whether the combination of quick nitrogen testing and weather-based irrigation scheduling could reliably reduce the amount of nitrogen that lettuce growers apply.
“We demonstrated a 30-percent reduction in nitrogen fertilizer application,” Cahn said.
The excitement of such a significant result was tempered by the fact that implementing the research results on individual farms would require some serious math.
“When we introduced farmers to the quick nitrate test, some said they would have to hire someone to manage all the data, keep records and make decisions. I realized that we could make this a lot easier for them by programming software to do the work,” he said.
For example, farmers who wish to use weather data to schedule irrigation for lettuce must sign into CIMIS (California Irrigation Management Information Service) to request an email with reference evapo-traspiration for their locations. The data must be punched into an equation along with the irrigation coefficient for lettuce – a figure that represents how much water the lettuce needs – and the size of the lettuce canopy at the time of irrigation. This time-consuming data collection and manipulation is eliminated with CropManage.
“We’ve figured out how to facilitate all these calculations,” Cahn said.
“In effect, they set up a virtual ranch,” Cahn said.
When the farmer is ready to plant, the type of crop and results of a nitrogen quick test are added.
“The program recommends how long and when the irrigation should run and how much nitrogen, if any, should be added,” Cahn said. “The recommendations are updated automatically, taking into consideration the weather and the crop’s stage of growth.”
Throughout the growing season, farmers can monitor the progress of their farms by viewing online tables where irrigation, fertilization and growth are tracked. At any time, all the data can be downloaded as an Excel file the farmer can using for accounting or making reports.
Corey Ranch manager Montes said he accesses CropManage on a tablet computer.
“It’s very easy to use,” Montes said. “It’s easy to log on, input information and read from the tables. I love it. It’s a great tool and is definitely going to help us manage our water and fertilizer in a better way.”
Currently, CropManage contains information for production of romaine lettuce, iceberg lettuce and broccoli. Strawberries and caneberry data will be added to the system. Research is underway on leafy greens, such as spinach and baby leaf lettuce, so they also can be added.
“Everything we learn in research, we will add to CropManage,” Cahn said. “And by using it, growers can give us feedback on how accurate the system is. This is a fluid product. If growers find something that doesn’t work, we can change it.”
All the information uploaded to CropManage is held confidentially and secure on a UC server, protected with a private email address and password. The CropManage website’s privacy policy outlines setup options for users who wish to remain completely anonymous.
Development of the website was supported by a grant from the California Department of Agriculture Fertilizer Research and Education Program.
For more information about the 2013 Irrigation and Nutrient Management Meeting on Feb. 26 or about CropManage, contact Cahn at (831) 759-7377, mdcahn@ucanr.edu.
- Author: Pamela Kan-Rice
The Pistachio Research Board will donate $1.5 million to support a UC Cooperative Extension specialist to conduct nut and fruit disease research. This specialist position, which will be based in the Department of Plant Pathology at UC Davis and housed at Kearney Agricultural Research and Extension Center in Parlier, will help UC ANR fulfill its mission as well as serve the pistachio industry’s needs.
“On behalf of California’s pistachio growers, the California Pistachio Research Board is pleased to invest in the research and extension activities of the University of California and particularly UC Cooperative Extension,” said Bob Klein, manager of the California Pistachio Research Board.
“California farmers, especially pistachio growers, know that research is needed to maintain and improve food production while using our resources wisely and sustainably,” he said. “This position will help address the ever-changing plant disease spectrum in the state, as well as respond to new regulations on both the state and federal levels.”
“The nut and fruit crop pathology specialist was identified as a priority position for UC ANR in our position planning process, and the Pistachio Research Board’s generous gift and foresight enables us to begin recruiting immediately,” Allen-Diaz said. “The board’s six-year commitment gives the position stability. After six years, UC ANR will assume financial responsibility for the position.”
This is the third UC Cooperative Extension academic position funded through a partnership between the agricultural community and UC ANR. The California Rice Research Board and the California Table Grape Commission were the first to partner with the university in this new public-private funding model to fund UC Cooperative Extension positions.
“Hiring outstanding academics to do research and deliver new knowledge is critical to the sustainability of farmers and to the future of California,” said Allen-Diaz. “This new funding model will enable us to act now to work on needed research and deliver science-based solutions.”
“We value our partnership with the UC and will continue to invest in additional research positions as well as support the ongoing research and extension activities of UC scientists,” Klein said.
To discuss potential partnership opportunities to fund academic positions, contact Cindy Barber at Cynthia.Barber@ucop.edu or (510) 987-9139.
