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Posts Tagged: aphid

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

Sugarcane Aphid - an Unwelcome Visitor to California's Central Valley

Sorghum is grown in California as a high yielding, drought resistant, low input forage and grain crop. However, it's been bugged lately. Last...

Posted on Friday, October 5, 2018 at 12:25 PM

The Incredible Aphid-Eating Machines

Just call them the "incredible aphid-eating machines." That would be the lady beetles, commonly known as ladybugs (although they are not bugs;...

Lady beetle larva dining on aphids on milkweed, UC Davis campus. (Photo by Kathy Keatley Garvey)
Lady beetle larva dining on aphids on milkweed, UC Davis campus. (Photo by Kathy Keatley Garvey)

Lady beetle larva dining on aphids on milkweed, UC Davis campus. (Photo by Kathy Keatley Garvey)

A lady beetle, aka ladybug, tracks down more prey. (Photo by Kathy Keatley Garvey)
A lady beetle, aka ladybug, tracks down more prey. (Photo by Kathy Keatley Garvey)

A lady beetle, aka ladybug, tracks down more prey. (Photo by Kathy Keatley Garvey)

Posted on Thursday, August 30, 2018 at 5:38 PM
Focus Area Tags: Agriculture, Environment, Natural Resources, Pest Management, Yard & Garden

Be on the lookout for sugarcane aphid this summer

Last year many forage sorghum fields were heavily infested and damaged by Sugarcane Aphid (SCA) (Figure 1) – Melanaphis sacchari –...

Posted on Friday, July 7, 2017 at 3:01 PM
Tags: IPM (0), Pest Mangement (0), Sorghum (0), Sugarcane Aphid (0)

The blue alfalfa aphid: A continuing problem into 2015

Basic background and biology of the blue alfalfa aphid: The blue alfalfa aphid (Acyrthosiphon kondoi Shinji) was first identified by entomologists...

Posted on Wednesday, August 5, 2015 at 12:13 PM
  • Author: Vonny M. Barlow
Tags: Alfalfa (0), blue alfalfa aphid (0), IPM (0)

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