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.

FDA Releases Possible Factors for 2018 E. Coli Outbreaks

Leafy Greens Industry and Public Were Severely Impacted

By Hank Giclas, Western Growers Sr. Vice President, Strategic Planning, Science & Technology

Recently, the U.S. Food & Drug Administration released an environmental assessment that provides an overview of factors that potentially contributed to the contamination of romaine lettuce with E. coli that was implicated in a 2018 multi-state foodborne illness outbreak. The assessment can be found here and includes the background on the outbreak; the environmental team approach; and factors potentially contributing to the introduction and spread of E. coli; along with recommendations for the prevention E. coli in leafy greens.

FDA recommends that growers and processors of leafy greens:

  • assure that all agricultural water (water that directly contacts the harvestable portion of the crop) used by growers is safe and adequate for its intended use (including agricultural water used for application of crop protection chemicals);
  • assess and mitigate risks related to land uses near or adjacent to growing fields that may contaminate agricultural water or leafy greens crops directly (e.g. nearby cattle operations or dairy farms, manure or composting facility);
  • verify that food safety procedures, policies, and practices, including supplier controls for fresh-cut processors, are developed and consistently implemented on farms (both domestic and foreign) and in fresh-cut produce manufacturing/processing food facilities to minimize the potential for contamination and/or spread of human pathogens;
  • when a foodborne pathogen is identified in the growing or processing environment, in agricultural inputs (e.g., agricultural water), in raw agricultural commodities or in fresh-cut, ready-to-eat produce, a root cause analysis should be performed to determine the likely source of the contamination, if prevention measures have failed, and whether additional measures are needed to prevent a reoccurrence; and
  • Local in-depth knowledge and actions are critical in helping resolve potential routes of contamination of leafy greens in the Yuma growing region, including Imperial County and Yuma County, moving forward. FDA urges other government and non-government entities, produce growers and trade associations in Yuma and Imperial Counties to further explore possible source(s) and route(s) of contamination associated with the outbreak pathogen and with other foodborne pathogens of public health significance. This information is critical to developing and implementing short- and long-term remediation measures to reduce the potential for another outbreak associated with leafy greens or other fresh produce commodities.

The findings in the Environmental Assessment appear to provide little new information but will be closely reviewed by Western Growers and others as part of our industry’s ongoing efforts to ensure food safety.

Immediately after the outbreak, Western Growers collaborated with the leafy greens industry to help lead a task force that would assess the source of the outbreak, as well as develop recommendations to prevent future outbreaks. While sources of contamination remain uncertain, the task force made concrete recommendations to industry for assuring water is safe and adequate, assessing and mitigating risk from adjacent land uses as well as others to address risks from equipment and climatic conditions.  These recommendations go well beyond the requirements of the FDA’s own Produce Safety Rule and have already been incorporated into the California and Arizona LGMA requirements. State auditors are now charged with verifying adherence to these new controls through announced and un-announced audits that occur throughout the seasons. The industry is furthering its efforts to learn more including through research guided by respected entities such as the Center for Produce Safety and working directly with California and Arizona academic teams. There is a strong and broad commitment to continually work to improve our food safety system.

Other related information posted by FDA includes:

USDA Designates Imperial County as Primary Natural Disaster Area

Drought-Ridden Imperial County Named Primary Natural Disaster Area 

TODAY, the U.S. Department of Agriculture (USDA) designated Imperial County in California as a primary natural disaster area due to damages and losses caused by a recent drought.

“Our hearts go out to those California farmers and ranchers affected by recent natural disasters,” said Agriculture Secretary Tom Vilsack. “President Obama and I are committed to ensuring that agriculture remains a bright spot in our nation’s economy by sustaining the successes of America’s farmers, ranchers, and rural communities through these difficult times. We’re also telling California producers that USDA stands with you and your communities when severe weather and natural disasters threaten to disrupt your livelihood.”

Imperial County, CA
Imperial County, CA

Farmers and ranchers in Riverside and San Diego Counties in California also qualify for natural disaster assistance because their counties are contiguous.

Farmers and ranchers in La Paz and Yuma Counties in Arizona also qualify for natural disaster assistance because their counties are contiguous.

All counties listed above were designated natural disaster areas TODAY, making all qualified farm operators in the designated areas eligible for low interest emergency (EM) loans from USDA’s Farm Service Agency (FSA), provided eligibility requirements are met. Farmers in eligible counties have eight months from the date of the declaration to apply for loans to help cover part of their actual losses. FSA will consider each loan application on its own merits, taking into account the extent of losses, security available and repayment ability. FSA has a variety of programs, in addition to the EM loan program, to help eligible farmers recover from adversity.

Additional programs available to assist farmers and ranchers include the Emergency Conservation Program, The Livestock Forage Disaster Program, the Livestock Indemnity Program, the Emergency Assistance for Livestock, Honeybees, and Farm-Raised Fish Program, and the Tree Assistance Program. Interested farmers may contact their local USDA Service Centers for further information on eligibility requirements and application procedures for these and other programs. Additional information is also available online at http://disaster.fsa.usda.gov.