Lettuce Aphids Showing Up on Late Produce

Lettuce Aphid Pressure Has Been Steady

By John Palumbo, University of Arizona Professor/Extension Specialist, Department of Entomology

This season has been a banner year for aphids in the desert.  Aphid pressure has been steady on most crops throughout the spring.  Consistent with the warm weather we have been experiencing lately, Lettuce aphids, Nasonovia ribisnigri, (aka., Red aphid) have shown up in desert lettuce again.

The last time lettuce aphid was this abundant on desert produce was the spring of 2012.  However, in the past couple of weeks, I’ve identified lettuce aphid appearing on both head lettuce and romaine in Roll and Wellton. I’ve also had reports of the aphid showing up in the Imperial Valley.

At the Yuma Ag Center, we began seeing lettuce aphid a couple of weeks ago on untreated lettuce, and they have recently built up to high numbers. Previous experience has taught us that daytime high temperatures in the 80’s are ideal for population growth.  A few things to remember about lettuce aphids relative to the other aphids we commonly see.

First, the immature nymphs are small and have a red appearance, whereas the apterous adults are typically a large brown colored aphid with dark bands running across the abdomen.  Second, among the crops we grow locally, lettuce aphids are only found on the lettuce types(Lactuca spp.)

Lettuce aphids prefer to colonize the terminal growth, and can often be found in heads or hearts, whereas green peach aphids are often found on the frame leaves in high numbers before moving into the heads. Sampling should be focused on the terminal growth of young plants and in the heads and hearts of older plants. Third, they can reproduce prolifically, producing many more winged alates than other species, which can quickly lead to widespread abundance throughout a field or a growing area.  Finally, as the saying goes “he who hesitates is lost”.

If lettuce aphids are found on your lettuce, it is recommended that you respond quickly with an insecticide treatment. The product of choice is Movento at 5 oz/ac. Because of its systemic activity, Movento will reach aphids in the protected terminal growth.

Be sure to include a penetrating adjuvant for best results at a rate of at least 0.25% v/v. It normally requires 7-10 days of activity before a significant reduction in the infestation is observed. For more information on lettuce aphid please refer to Lettuce Aphid on Late Season Produce.   If you’re finding lettuce aphid on organic lettuce, you’re out of luck; none of the registered biopesticides will control this aphid.

Gary Schulz Gives California Citrus ACP and HLB Update

California Citrus ACP and HLB Update from Gary Schulz

By Brian German, Associate Broadcaster

 

The Citrus Research Board (CRB) recently held their annual California Citrus Conference in Exeter, bringing together a variety of guest speakers and research presentations. The Conference focused on pressing Asian Citrus Psyllid (ACP) and Huanglongbing (HLB) issues, along with political action updates and current projects that are important to the citrus industry. Gary Schulz, president of the CRB, said “We have a 21-member board and we’ve been planning this event for the last 12 months. It’s been 4 years since we held the last conference,” noted Schulz.

Gary Schulz, president, Citrus Research Board
Gary Schulz, president, Citrus Research Board

The CRB is responsible for overseeing the California Citrus Research Program (CCRP), a grower-funded and grower-directed program created in 1968 under the California Marketing Act. The CCRP’s purpose to enable California’s citrus producers to sponsor and support research that furthers the overall industry. Therefore, close to 70 percent of the CRB’s overall budget is allocated to research.

Schulz said the Conference “was a great, great day to have a good update on some of the dollars the Citrus Research Board has been spending on the growers’ behalf on research.” Schulz explained HLB represents the single greatest threat that citrus growers have faced worldwide.

For the past seven years, the USDA and Congress have allocated between $10 and $12 million dollars annually for ACP and HLB research operations.  Advocacy groups and other supportive ag organizations have contributed the difference to reach an annual ACP and HLB research budget of close to $90 million dollars a year. We fund a lot of UC Riverside and USDA agricultural research, service researchers, plus research at UC Davis and the University of Arizona,” Schulz noted.

Schulz, who has many years of experience in California agriculture, having served as general manager of the Raisin Administrative Committee and CEO of the California Raisin Marketing Board, stated that CRB has a great working relationship with California Citrus Mutual (CCM). “Joel Nelson and CCM have worked very hard with the packers to assess themselves, put together a private foundation, and work with the university,” Schulz said.

Featured Photo:  Adult Asian Citrus Psyllid (Source: The Citrus Pest & Disease Prevention Program)


Resources

California Marketing Act

Citrus Research Board (CRB)

California Citrus Mutual