UCCE Sonoma County
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Posts Tagged: lettuce

UCCE advisor is tracking down answers to a lettuce aphid mystery

When Alejandro Del Pozo-Valdivia started his new job as UC Cooperative Extension entomology advisor in the Salinas Valley last year, he immediately faced an urgent problem in organic lettuce production.

Pest control advisers were finding lettuce aphids in plants that were supposed to be resistant.

Because lettuce aphids crawl deep within the heart of the lettuce head, and because organic growers do not have many options for chemical pest control, the industry relies on patented lettuce varieties that have been conventionally bred to be unpalatable to the pest.

Alejandro Del Pozo-Valdivia, UC Cooperative Extension entomology advisor in Monterey, Santa Cruz and San Benito counties, in an iceberg lettuce field in Chualar, Calif.

“With other types of aphids, they stay on the outer leaves. When you harvest and clean the head, you are taking the aphids out,” Del Pozo-Valdivia said. “But with the lettuce aphid, it's almost impossible to remove them. We don't want consumers to buy a lettuce with these tiny red insects inside.”

Organic producers pay a premium for resistant seeds to grow lettuce without the lettuce aphid and are mystified by the sudden appearance of the pest inside lettuce heads. Has the aphid developed the capability to feed on resistant varieties? Is there a different lettuce aphid biotype in the area? Since Del Pozo-Valdivia is an entomologist, he is focusing on the pest.

With funding from the California Leafy Green Research Board, Del Pozo-Valdivia and his co-principal investigator, USDA scientist Jim McCreight, have launched a research project to collect and identify the lettuce aphids that are feeding and reproducing in the resistant lettuce in the Salinas Valley.

“I'm asking growers and PCAs to contact me if they find any red aphids in resistant lettuce so we can confirm the type of aphid,” Del Pozo-Valdivia said. “

Comparison between a healthy lettuce plant (right) vs. aphid-infested lettuce (left). Plants were grown inside a greenhouse to sustain a lettuce aphid colony during 2018. (Photo: A. Del Pozo-Valdivia)

Seed companies that hold the patent on resistant lettuce also experienced broken resistance in Europe a few years ago, Del Pozo-Valdivia said. They found that the pest in Europe was a different biotype and are already working on identifying genes to maintain the lettuce aphid resistance.

“We haven't seen any scientific report for the U.S. That's why we decided to take the lead. To take the bull by the horns and identify the aphids here in the Salinas Valley,” Del Pozo-Valdivia said.

The lettuce aphid, Nasonovia ribisnigri. A distinct feature of this aphid is the presence of black stripes at the abdomen of the adults. This species is one of the most difficult aphids to manage in lettuce; since colonies are formed inside (inner leaves) of the lettuce head. (Photo: A. Del Pozo-Valdivia)
Posted on Friday, May 17, 2019 at 8:55 AM
Focus Area Tags: Pest Management

Drip-applied Kerb (Pronamide) in lettuce

Figure 1. Untreated plot (left) and Pronamide (Kerb at 2.5 pints/A) applied via drip tape (right) 30 days after transplanting of romaine lettuce. Areas most distant from drip tape that supplied herbicide show weed survivorship.

Over the years of Kerb use in lettuce (more like decades) there has been a lot of work on application methods. Our transplanted lettuce in southern California is usually grown on drip and when possible, we like to apply all things through it. Our fields are surrounded by four cities and folks there...

Posted on Tuesday, January 29, 2019 at 3:24 PM
Focus Area Tags: Agriculture Pest Management

Spray materials for automated thinners and weeders

Untreated control

Automated lettuce thinners that use a spray mechanism to remove unwanted lettuce plants and weeds have been widely adopted in the Salinas Valley and desert production districts. The machines utilize a camera to capture images of the lettuce plants in the seedline, calculate plants that need to be...

Posted on Tuesday, May 30, 2017 at 1:44 PM
Tags: Lettuce (17), wee (1), weed control (81), Weeds (65)

'Agriculture: Food for Life' is the theme of National Ag Week

How are you celebrating American agriculture in your life? In advance of National Ag Week, March 19-25, and National Ag Day, March 21, Central Valley third-grade students were “learning with lettuce” how to bring more agriculture into their lives last week. The UC Kearney Agricultural Research and Extension Center offers the free lettuce plantings every year at Farm and Nutrition Day in Fresno County and Kings County, typically around the time of National Ag Week.

National Ag Week and National Ag Day celebrate American food, fiber and fuel producers and their important contributions to our lives.

Volunteers enjoyed working with each student to get their seedling off to a great beginning.

Students with the help of volunteers learned how to plant tiny lettuce seedlings into a pot of healthy soil to take home for transplanting later. In addition to helping the students connect their food to agriculture, the lettuce planting offered an engaging, hands-on experience growing healthy and nutritious food at home.

Third grade students from Fremont Elementary School joined classmates on their way to Kearney's lettuce planting at last year's Farm and Nutrition Day.

 

Julie Sievert and Laura Van Der Staay prepared a lesson that teaches students about the parts of a plant and what a plant needs to grow our food, fiber and fuel crops.

National Ag Week is a nationwide effort coordinated by the Agriculture Council of America to tell the vital story of American agriculture and remind citizens that agriculture is a part of all of us. National Ag Day encourages every American to:

• Understand how food and fiber products are produced.
• Appreciate the role agriculture plays in providing safe, abundant and affordable products.
• Value the essential role of agriculture in maintaining a strong economy.
• Acknowledge and consider career opportunities in the agriculture, food and fiber industry.

 
Kearney director Jeff Dahlberg was interviewed about Kearney's education and outreach programs.

Each American farmer feeds about 144 people. As the world population soars, there is even greater demand for the food, fiber and renewable resources produced in the United States. Agriculture is this nation's #1 export and incredibly important in sustaining a healthy economy. That's why National Ag Week is a great time to reflect on and be grateful for American agriculture.

With lettuce seedlings in hand, happy junior gardeners were ready to continue the learning experience at home.

 

Central Valley students eagerly lined up to get started on their lettuce planting fun.
Posted on Friday, March 24, 2017 at 8:45 AM
  • Author: Roberta Barton
Tags: agriculture (37), food (59), healthy (3), Kearney (8), lettuce (17), National Ag Day (1), National Ag Week (1), UC (3)

Federal Label for Kerb Regained

The following information is from the Salinas Valley Agriculture blog. On January 12, 2016 the Federal EPA label for Kerb SC was reinstated for leaf lettuce. The registration on leaf lettuce was pulled in 2009 and Dow AgroSciences has been working to reregister Kerb since that time. As part of...

Posted on Friday, January 22, 2016 at 7:56 AM
Tags: herbicide (56), Lettuce (17), Vegetable Crops (16)

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