Tomato Spotted Wilt Virus Fights Back

New Strain Creates Challenges

By Mikenzi Meyers, Associate Editor

A new strain of the Tomato Spotted Wilt Virus has created a challenge among vegetable growers, making integrated pest management, or IPM, increasingly critical. Bob Gilbertson, plant pathologist at UC Davis, has insight and advice as to how farmers should tackle this new strain.

“The first thing is to know what’s out in your field. And there’s a good diagnostic test for curly top, spotted wilt, alfalfa mosaic, and other viruses,” Gilbertson said.

Bob Gilbertson

After the virus is confirmed, he encourages growers to explore their options of treatment. Prior to the new spotted wilt virus strain, growers could turn to the SW-5 resistance gene to cure their field. Unfortunately, Gilbertson explained, the new strain actually breaks that resistance, which is where IPM becomes even more important.

In the future, Gilbertson hopes to find additional resistance genes to break the new strain. Until that time comes, he wants to use good IPM to manage it.

Gilbertson further added, “Increased sanitation, removing overwintering hosts, weeds, and bridge crops like lettuce, and then timing the applications of thrips management better, to slow down the appearance of adult thrips that carry the virus,” are all examples of good IPM.

More California Ag News

Curly Top Virus Light In 2018 CDFA Surveys Predict Curly Top Vectored by Leafhoppers By Patrick Cavanaugh, Editor Curly top virus is a common disease in California. In its worst ...
Hybrid Peppers on the Rise Seminis Brings Extensive Experience By Jessica Theisman, Associate Editor Before 2001, there were no hybrid Habanero Peppers. Terry Burke, hot peppe...
Expert Talks Protecting Our Food Supply And Indust... Maintaining Food Safety - Part 2 By Patrick Cavanaugh, Farm News Director Continuing our series on food safety in the state of California, we spoke ...
Berry Industry Without Methyl Bromide Berry Industry Must Now Work Smarter in Post Methyl Bromide Era By Patrick Cavanaugh, Editor The strawberry fruit production industry, with the exce...

Curly Top Virus Light In 2018

CDFA Surveys Predict Curly Top Vectored by Leafhoppers

By Patrick Cavanaugh, Editor

Curly top virus is a common disease in California. In its worst years, entire fields have been lost to curly top in the foothills of the Central Valley, and it can infect a variety of plants from a total of 44 plant families as well as 300 individual species.

Curly top commonly affects tomatoes, peppers, beets, spinach, potatoes, and beans, as well as a variety of weeds. A common characteristic of curly top is stunting of the plant as well as curling and twisting of the leaves, where it gets its name, curly top. Leafhoppers are the main vector of the virus.

Currently, the CDFA conducts a yearly curly top prediction where they monitor numbers and the leafhopper population as well as the prevalence of the virus to give a scope of what the upcoming year might look like.

“Curly top virus was very low in 2018 as predicted—based on the amount of virus carried by the leafhoppers and the leafhopper population,” said Bob Gilbertson, Plant Pathologist, Department of Plant Pathology at UC Davis.

“We hope that CDFA will continue to carry out the leafhopper screening for the virus and for the population so growers get a prediction of what the curly top incidents will be the coming year,” Gilbertson said. “It’s good that we can tell growers when there’s going to be a bad curly top year so they can implement additional strategies.”

These strategies include changing where they’re going to plant a field or using timed insecticides, particularly systemic insecticides like the new Verimark (From FMC) insecticide to manage curly top.

“We’ve already found that that material can slow down the spread of curly top in a field,” Gilbertson explained. “So in a year where it’s predicted to be bad—high populations of leafhoppers carrying high amounts of the virus—then you as a grower would then want to consider using some of these insecticide approaches.”

More California Ag News

Hybrid Peppers on the Rise Seminis Brings Extensive Experience By Jessica Theisman, Associate Editor Before 2001, there were no hybrid Habanero Peppers. Terry Burke, hot peppe...
Strawberry Commission Oversees Valuable Crop Strawberries in California By Jessica Theisman, Associate Editor Strawberries are California's sixth most valuable crop which makes strawberry resea...
Citrus Mutual Encouraged by Farm Bill California Citrus Mutual Commends Congress for Action on 2018 Farm Bill News Release This week, the U.S. Senate and the House passed the Agriculture...
Preventing the Spread of ACP Valley Citrus Growers Continue Vigilance By Jessica Theisman, Associate Editor The spread of Asian Citrus Psyllid (ACP) continues to be a loomin...

Walnut Blight Protection is Important

Disease Prevention in Walnut Orchards

By Brianne Boyett, Associate Editor

California Ag Today recently spoke with Jim Adaskaveg, professor of plant pathology at UC Riverside. He’s a plant pathologist, microbiologist and epidemiologist. He discussed the importance of protecting walnut trees from walnut blight.

Adaskaveg explained how walnut blight is problematic due to the higher rainfall in the northern part of the state.

“We’ve been working on this for a number of years, and overall, the northern part of the state is always higher at risk because of the higher rainfall in Glenn County,” he said. “There is much higher risk for disease in Northern California, so a lot of the growers have planted later blooming varieties such as Chandler to avoid the blight infections.”

“Rick Buchner [at UC Cooperative Extension] Tehama County and his group called that the prayer stage, which is when the female flower becomes exposed as it emerges from the bud. Those two timings would be for high disease pressure. If you had a history of the disease and you know that the disease is in your orchard, then we would suggest that timing,” Adaskaveg said.

“If you don’t have disease, and you still want to protect yourself, we say just spray at the pistillate flower emergence or the prayer stage. That sets a good way to initiate the spray program,” Adaskaveg explained.

Growers must keep in mind canopy expansion when applying materials.

“Walnuts are big trees, and as they go through bloom, all the leaves started emerging almost weekly. The tree canopy in that first three weeks of the season is doubling in size. By the time you get three or four weeks after that, the catkin flowering trees in full canopy will require a reapplication of materials,” Adaskaveg said.

More California Ag News

Almond Band Canker has No Cure Almond Band Canker Creeping up Again By Patrick Cavanaugh, Farm News Director Themis Michailides, a UC Davis Plant Pathologist based at the Kearney ...
Navel Orangeworm Control Critical Orchard Sanitation is Critical This Season To Lower NOW Numbers By Patrick Cavanaugh, Farm News Director Emily Symmes is the area Integrated Pest Ma...
Farmers Encouraged to Fill Out Ag Census 2017 Ag Census Under Way By Jessica Theisman, Associate Editor California Ag Today recently spoke with Scot Rumburg, the Nevada State Statistician f...
Measuring Crop Protection Material Tolerances Biological Tolerances May Be Needed By Patrick Cavanaugh, Farm News Director California Ag Today recently spoke with Gabrielle Ludwig, Director of S...

Greg Douhan is New Citrus Farm Advisor

UCCE Tulare Welcomes New Citrus Farm Advisor

By Brian German, Associate Director

The UC Cooperative Extension Program has served Tulare County since 1918 and continues to meet the ever-changing needs of the community. UC Cooperative Extension, Tulare County is preparing to welcome their new citrus farm advisor, Greg Douhan, on March 1, 2016. Douhan, who noted his excitement for the opportunity, will be taking the reins from the recently retired Neil O’Connell who gave over 34 years of faithful service advising Tulare County citrus growers.

Douhan shared that his relatives inspired him to focus his career in agriculture. “I had an uncle who was an almond grower when I was a kid. And my grandfather was an avid horticulturalist; he used to graft different trees and I always found that fascinating.”

“As I got older, I decided I was interested in plants, so I went to Humboldt State University. I also got interested in fungi, so I decided to fuse my interests in fungi and in plants and go into plant pathology,” Douhan said.

“I earned my Master’s and Ph.D. at Washington State University, and then completed a post-doc assignment at UC Davis for 3-4 years. I moved to UC Riverside for about 6 years. Now I am here in Tulare County!” 

Cooperative Extension advisors serve as conduits of information from various UC campuses. Subject matter specialists, along with local research centers, collaborate with local advisors to identify and solve local problems through research and educational programs. The mission of the program is to serve California through the creation, development and application of knowledge, in agriculture, natural and human resources. Farm advisors then apply this knowledge to improve our agriculture and food systems along with our natural resources and environment.

“I’ve been working for the UC system basically since I was a post-doc,” Douhan said, “so it has been for many years. I think Cooperative Extension was the best system for working with both the growers and everybody else to better California agriculture,” Douhan said. “This was just an incredible opportunity. I was doing science and looking for another career move, and this was a perfect opportunity to have a next chapter in doing something different.”

_______________________

Link:

Tulare County Cooperative Extension

More California Ag News

BIG WATER RALLY SCHEDULED FOR JAN. 16! Thousands Needed To Participate In Big Water Rally on Jan. 16  
Solano County 4-H Clubs Win Big at Skills Day When Life Gives you Lemons, Make Lemon Curd! Showmanship winner Tyler Scott of the Wolfskill 4-H Club DIXON--Tyler Scott of the...
California Ag News UC To Help Ranchers UC to Help Ranchers Survive Winter 2013-14 The first agricultural operations to feel the impact of a drought are dryland ranchers, many of whom r...
MONTEREY FARM BUREAU WARNS CPUC ON WATER ISSUES Desalination Plant Could Jeopardize Groundwater Supply California American Water could threaten the ground water supply of the Salinas Valley where u...

New UC IPM Program Director

Jim Farrar Named Director of UC Statewide IPM Management Program

By Pam Kan-Rice, UCANR Assistant Director, News and Information Outreach

Jim Farrar has been named director of the Statewide Integrated Pest Management Program for the University of California’s Division of Agriculture and Natural Resources. He will begin as new uc ipm program director on Oct. 1.

UC IPM works with growers and residents to protect human health and the environment by reducing risks caused by pests and pest management practices.

Farrar is currently director of the Western IPM Center, where he has served since 2013. He succeeds Kassim Al-Khatib, UC IPM director since 2009, who is transitioning to a UC Cooperative Extension specialist position located in the Department of Plant Sciences at UC Davis. There Al-Khatib will focus on his research in weed management.

“UC IPM is a widely recognized national leader in integrated pest management,” Farrar said. “I am excited to continue efforts to make IPM the standard practice for managing pests in agriculture, communities and natural areas in California.”

Prior to joining the Western IPM Center, Farrar was a professor of plant pathology in the Department of Plant Science at California State University, Fresno for 12 years.

At Fresno State, Farrar received three teaching awards. He taught courses in plant pathology, plant nematology, diagnosis and control of plant diseases, crop improvement, aspects of crop productivity, mycology, sustainable agriculture and advanced pest management. His research centered on fungal diseases of vegetable crops, including management strategies for cavity spot of carrot. During his Fresno State tenure, he served four years as chair of the Department of Plant Science and a year as interim chair of the Department of Food Science and Nutrition.

From 1995 to 1997, Farrar taught in the Botany Department at Weber State University in Ogden, Utah. At Weber State, he conducted research on rock cress plants infected with a rust fungus that causes false-flowers. This rust is closely related to a species that is a potential biological control agent for dyer’s woad (Isatis tinctoris), an invasive weed.

Farrar has published scientific papers, extension newsletter articles, and articles in agricultural industry magazines. He also wrote a chapter in the book Tomato Health Management and five disease descriptions in the book Compendium of Umbelliferous Crop Diseases. He recently completed a three-year term as senior editor for feature articles in the journal Plant Disease and was senior editor for the online journal Plant Health Progress for three years. Farrar is a member of the American Phytopathological Society and the Pacific Division of the American Phytopathological Society.

The Wisconsin native completed his Ph.D. in botany and B.S. in plant pathology at the University of Wisconsin, Madison, and his M.S. in plant pathology at UC Davis.

 

More California Ag News

BIG WATER RALLY SCHEDULED FOR JAN. 16! Thousands Needed To Participate In Big Water Rally on Jan. 16  
Solano County 4-H Clubs Win Big at Skills Day When Life Gives you Lemons, Make Lemon Curd! Showmanship winner Tyler Scott of the Wolfskill 4-H Club DIXON--Tyler Scott of the...
California Ag News UC To Help Ranchers UC to Help Ranchers Survive Winter 2013-14 The first agricultural operations to feel the impact of a drought are dryland ranchers, many of whom r...
MONTEREY FARM BUREAU WARNS CPUC ON WATER ISSUES Desalination Plant Could Jeopardize Groundwater Supply California American Water could threaten the ground water supply of the Salinas Valley where u...