trans1_small
University of Arizona
When autocomplete results are available use up and down arrows to review and enter to select.
  • Home
  • Pest Identification
    • Pest Identification Home
    • Diseases
    • Weeds
    • Insects
    • Pest Diagnostics
    • Pest Identification - Outputs
    • Events
    • Frequently Asked Questions
  • Agricultural IPM
    • Agricultural IPM Home
    • Vegetables
    • Field Crops
    • Other Crops
    • Agricultural Pesticide Safety
    • Agricultural IPM Outputs
    • Events
    • Frequently Asked Questions
  • IPM Assessment
    • IPM Assessment Home
    • Crop Pest Losses
    • Impacts
    • EPA Pesticide Registration Reviews
    • How To Submit Comments to EPA
    • Previously Submitted EPA Comments
    • Projects
    • IPM Assessment Outputs
    • Frequently Asked Questions
  • Community IPM
    • Community IPM Home
    • School IPM
    • Public Health IPM
    • Turfgrass
    • Community Pesticide Safety
    • Community Insect Gallery
    • Handbook on Pests
    • Home and School IPM Newsletters
    • Community IPM Resources
    • Events
    • Frequently Asked Questions
  • Pesticide Education and Training
    • Pesticide Education and Training Home
    • Ag Licensing Resources
    • Community Licensing Resources
    • Special Pesticide Registrations
    • Pesticide Safety Outputs
    • Events
    • Frequently Asked Questions
  • About Us
    • Partners and Links
    • Contact Us
    • Organizational Chart
    • Arizona Pest Management Center
    • Mission
    • Working Groups
    • Organization
    • Social Media
  • Home
  • Pest Identification
    • Pest Identification Home
    • Diseases
      • Publications And Resources
      • Photo Gallery
    • Weeds
      • Sample Submissions
      • Publications And Resources
      • Noxious Invasive Weeds
      • Weed Photo Gallery
      • Herbicide Injury
    • Insects
      • Sample Submissions
      • Publications And Resources
      • Insect Collection
      • Photo Gallery
      • Insect Injury
      • Community Insect Gallery
    • Pest Diagnostics
      • Herbicide Injury
      • Insect Injury
      • Publications And Resources
      • Photo Gallery
    • Pest Identification - Outputs
      • Presentations
      • Publications
      • Shorts
      • Medias
    • Events
    • Frequently Asked Questions
  • Agricultural IPM
    • Agricultural IPM Home
    • Vegetables
      • Lettuce
        • Crop Management
        • Soil Management
        • Irrigation
        • Varieties
        • Insects
        • Diseases
        • Weeds
      • Melons
        • Crop Management
        • Soil Management
        • Irrigation
        • Varieties
        • Insects
        • Diseases
        • Weeds
      • Cole Crops
        • Crop Management
        • Soil Management
        • Irrigation
        • Varieties
        • Insects
        • Diseases
        • Weeds
      • Spinach
        • Crop Management
        • Soil Management
        • Irrigation
        • Varieties
        • Insects
        • Diseases
        • Weeds
      • Vegetable Outputs
        • Presentations
        • Publications
      • VIPM Updates
      • VIPM Archive
      • Vegetable Video Archive
      • VIPM Update Cartoons
      • Events
    • Field Crops
      • Alfalfa
        • Crop Management
        • Soil Management
        • Irrigation
        • Varieties
        • Insects
        • Diseases
        • Weeds
        • Pesticide
      • Corn and Sorghum
        • Crop Management
        • Soil Management
        • Irrigation
        • Varieties
        • Insects
        • Diseases
        • Weeds
        • Pesticide
      • Cotton
        • Crop Management
        • Soil Management
        • Irrigation
        • Varieties
        • Insects
        • Diseases
        • Weeds
        • Pesticide
      • Guayule
        • Crop Management
        • Soil Management
        • Irrigation
        • Varieties
        • Insects
        • Diseases
        • Weeds
        • Pesticide
      • Small Grains
        • Crop Management
        • Soil Management
        • Irrigation
        • Varieties
        • Insects
        • Diseases
        • Weeds
        • Pesticide
      • Risk Reduction
      • Outputs
        • Publications
        • Presentations
        • Videos
      • Events
      • Field Crops IPM Shorts
    • Other Crops
      • Citrus
      • Tree and Nut Crops
      • Cross Commodity
    • Agricultural Pesticide Safety
    • Agricultural IPM Outputs
      • Presentations
      • Publications
      • Agricultural IPM Shorts
    • Events
    • Frequently Asked Questions
  • IPM Assessment
    • IPM Assessment Home
    • Crop Pest Losses
      • Cotton Pest Losses
      • Vegetable Pest Losses
    • Impacts
    • EPA Pesticide Registration Reviews
    • How To Submit Comments to EPA
    • Previously Submitted EPA Comments
    • Projects
      • Crop Pest Losses
    • IPM Assessment Outputs
      • Presentations
      • Publications
      • Shorts
    • Frequently Asked Questions
  • Community IPM
    • Community IPM Home
    • School IPM
      • Stop School Pests
      • IPM for Sensitive Sites in the Built Environment
    • Public Health IPM
      • Arizona Conenose Bugs
      • Bed Bugs
      • Bees
      • Body Lice
      • False Chinch Bugs
      • Fire Ants
      • Head Lice
      • Longhorned Tick
      • Mosquitoes
      • Scorpions
      • EPA Border 2020
    • Turfgrass
      • Pre-emergence Weed Control - Lawns
      • History of the Lawn and Turfgrass
      • Nitrogen and Iron Deficiencies
      • Publications and Resources
    • Community Pesticide Safety
      • Presentations
      • Publications
    • Community Insect Gallery
    • Handbook on Pests
    • Home and School IPM Newsletters
    • Community IPM Resources
    • Events
      • 2021 Emergency Preparedness Workshop
      • 2022 Emergency Preparedness Workshop
    • Frequently Asked Questions
  • Pesticide Education and Training
    • Pesticide Education and Training Home
    • Ag Licensing Resources
    • Community Licensing Resources
    • Special Pesticide Registrations
    • Pesticide Safety Outputs
      • Presentations
      • Publications
      • Pesticide Safety Shorts
    • Events
    • Frequently Asked Questions
  • About Us
    • Partners and Links
    • Contact Us
    • Organizational Chart
    • Arizona Pest Management Center
    • Mission
    • Working Groups
    • Organization
    • Social Media
  1. Agricultural IPM
  2. Vegetables
  3. VIPM Archive
  4. VIPM Insect View
Insect Management
Oct 19, 2022
Don’t Forget About Corn Earworm in Lettuce

John Palumbo, Professor/Extension Specialist, Department of Entomology       

With early-planted head lettuce crops beginning to rosette and folding-in to form heads, it would be wise to keep a keen eye out for corn earworm (CEW).  This year could be particularly important as pheromone trap catches spiked last week in Wellton and Dome Valley.  Plus, the weather is optimal for CEW development.   Although pheromone trap counts don’t always correlate to field infestations, the last time we saw significant fall larval populations in the field was in 2014 and current moth counts are trending similar to what we experienced the fall of 2014.  With the calm, warm nights expected to continue for the next 10 days or so, above average moth activity should be expected. Lots of moths usually means lots of eggs.
CEW can be very damaging in early fall head lettuce crops. On older plants beginning to form heads, larvae will migrate to the succulent terminal growth. If not controlled before the plant leaves fold in, they are protected from foliar sprays. By this time in plant growth, at-planting soil applications of Coragen may not be effective enough to protect the heads. Once head formation begins, newly hatched larvae will usually bore into the head almost at once upon hatching.  Corn earworm is much more likely to bore into lettuce heads than other Lepidoptera larvae, rendering the heads unmarketable.  Larvae may enter the head from any point on the plants but can often be found burrowing in from the lower half of the head.  If fields are not watched closely, infestations may not be noticed until the head is harvested. Once inside the head, it is virtually impossible to control the larvae with insecticides. Thus, pay careful attention for newly oviposited eggs (laid singly) on lettuce plants. If you are beginning to find eggs and suspect that CEW are active in the field when plants are beginning to head or cup over, you should treat as soon as possible.  Moreover, during late October and early November it is probably a good idea to prophylactically apply a pyrethroid, methomyl or acephate in combination with another larvicides (e.g., Radiant, Coragen, Proclaim) when heads begin to form.  The UA nominal threshold for CEW in head lettuce from the beginning of heading to harvest is 1-2 larvae / 100 plants (1-2%).  Repeated insecticide treatments may be required to maintain low population levels if heavy pressure is sustained near harvest.  Lab bioassays have shown that CEW larval mortality is most rapid when exposed to Lannate, 0.5 lb (>90% mortality in 1 hr after exposure) and pyrethroids, high rates (>90% mortality in 3 hrs), followed by Radiant, 5 oz (>90% mortality in 12 hrs).  By 24 hrs, mortality was 100% for all the treatments including Coragen and Proclaim.  For more information on CEW management and control recommendations see Corn Earworm Management on Desert Produce  and the 2022 Lep Control Chart.

VIPM_10_19_2022_01

VIPM_10_19_2022_02

To contact John Palumbo go to: jpalumbo@ag.Arizona.edu
APMC Logo BW Inverted
CALS Logo Black and white Inverted
ARIZONA PEST MANAGEMENT CENTER
University of Arizona
College of Agriculture and Life Sciences
Maricopa Agricultural Center

37860 W. Smith-Enke Road
Maricopa, AZ 85239
FULL CONTACT
LIST
facebook
twitter


© Arizona Board of Regents

University Privacy Statement