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  • Alabama peanut production acres in 2008 = 191,000 acres; average state production = 3,300 lbs; total production = 630,000 lbs; value of crop = $73 million (2007 prices)

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  • 1. Scouting and Management Challenges for Soil Insect Pests of Peanut Ayanava Majumdar Extension Entomologist, ACES Gulf Coast Research and Extension Center 8300 State Hwy 104, Fairhope, AL 36532 Email: [email_address] Cell phone: 251-331-8416 Fax: 251-990-8912
  • 2. What attract insects to peanut pods? Insect types: Foliar insects Soil-air interface Exclusively soil dwelling CO 2 HEAT EXUDATES
  • 3. Burrower bugs
    • Host range: peanut, cotton, strawberry, spinach, wild plants
    • Identification: note wing structure, scutellum, & spines on legs
    • Damaging stages: adult, nymph
    • Mouthparts are inserted into maturing kernel
    • Cause light yellow/brown feeding spots OR “pitting”
    • Loss in kernel weight and no. of sound kernel
    • Increasing problem in conservation tillage systems
    Hemiptera: Cydnidae
  • 4. Scouting techniques (burrower bugs)
    • ET = 2 bugs per three feet row
    • Monitoring period: July – Aug.
    • Direct examination of pods (after the full seed, R6, stage)
    • Underutilized techniques: spade sampling/soil corer ? , light trap ? , pitfall trap √
    Pitfall trap with metal guide & cover Spade sampling
  • 5. Southern corn rootworm
    • Host range: 200 host plants, major pest of corn, sweet potato, peanut
    • Identification: wing pattern on adult beetles, larvae have 3 pr of legs
    • Damaging stage: larvae
    • Stand loss (early season damage)
    • Larvae make a hole on one side of the pod and feed on kernel
    • High OM, heavy soil >> high risk
    Coleoptera: Chrysomelidae
  • 6. Scouting techniques (southern corn rootworm)
    • ET: fresh damage evident OR larvae present in 1/3 rd sites
    • Electronic risk index by NCSU >> high risk (score 70+) in wet years, low risk (score <50) in well-drained soil
    • Larval infestation – scout close to pegging stage
    • Sweep net sampling for adults is reliable (10 sweeps/10 paces X 5 loc./A)…midmorning
    • Check pods for circular holes at one side (asymmetric)
  • 7. Lesser cornstalk borer
    • Occurrence: one of the major insect pests of peanut, sporadic
    • Host range: wide, hot-spots in peanut
    • Identification: larvae are blue-green with purple bands. Moths are grayish.
    • Larvae makes sand tubes on pods and stem (protection?)
    • Damaging stage: larvae feed just below soil surface
    • High risk to peanut in hot dry years, sandy soil
    • Worst of all… Aspergillus & aflatoxins
    Lepidoptera: Pyralidae
  • 8. Scouting techniques (lesser cornstalk borer)
    • ET – control when fresh damage is present OR when insect is recovered from 1/3 rd sample sites
    • Pod sampling – reliable indicator of infestation
    • Scouting maps available from AWIS website – based on the estimation of borer days on a scale of 0 to 5
  • 9. Wireworms
    • Host range: several plants (extended life cycle allows use of resources)
    • Identification: larvae with cylindrical body, wriggle furiously when touched, adults are click beetles
    • Damaging stage: larvae feed at various depths, major problem following sod
    • Saturated soil causes migration & spread
    • Make a large entry hole on one end
    Coleoptera: Elateridae
  • 10. Scouting techniques (wireworms)
    • Study field history – crop rotation, previous infestations
    • Germinating seed bait stations in soil – a reliable “relative sampling” technique
    • Seed baits could be deployed before planting peanut
    • Accuracy of seed baits improves with number of baits and experience of the field personnel
    • ET = 1 wireworm per bait station OR 30% pod damage
  • 11. Whitefringed beetles
    • Occurrence: native of S. Am., Naupactus species complex
    • Host range: 350 host plants – peanut, cotton, cowpea, alfalfa, okra
    • Identification: weevil w/out snout, adult has white stripes on sides, larva plump with strong mandibles
    • Damaging stages: larvae/grubs
    • Larvae make irregular holes in tap root, fatal to plants
    • Scouting: sweep net for beetles, leaf notching (visual scouting)
    • No insecticide registered
    Coleoptera: Curculionidae
  • 12. Cutworms
    • Host range: over 60 crops and turf, major pest of peanut
    • Identification: greasy plump caterpillars, larvae curl when touched
    • Overwintering stage: larva
    • Damage:
      • cut seedlings at night, may climb plants
      • larvae bore into the middle of peanut pod (large hole)
    Lepidoptera: Noctuidae Black CW Granulate CW
  • 13. Other sporadic insect pests White grubs ( Phyllophaga spp.) May/June Beetles 1-4 year life cycle Problem after sod Bahiagrass borer ( Derobrachus brevicollis) Large head of larva Problem after bahiagrass
  • 14. Scouting recommendations
    • Draw soil samples in Winter or Spring.
    • Reduce tendency to overestimate – increase sampling locations/numbers!
    • Use a variety of sampling methods – pheromone traps and germinating seed bait stations are cost effective!
    • Economic thresholds:
    • Burrower bug = 2 bugs per 3 foot row
    • LCB, SCRW = fresh damage or insect at 30% sites
    • Wireworms = 1 per bait station or 30 % pod damage
  • 15. Management of soil insects (peanut)
    • Future research directions:
    • Extend registration of new insecticides
    • Focus on bio-based soil insecticides as IPM partner
    • Survey of all major production areas (2009)
    • Establish economic threshold for emerging pests
    Cutworms Indoxacarb Cyfluthrin Gamma-cyhalo. Lamdba-cyhalo. Methomyl Zeta-cypermeth. LCSB Chlorpyrifos (banded over row and pegging zone) SCRW Chlorpyrifos (banded over row and pegging zone) Wireworms Chlorpyrifos (preplant broadcast spray on soil + incorporate OR banded) Burrower bugs Chlorpyrifos (banded over row)
  • 16. New Peanut Entomology Resources
    • ACES Factsheets:
      • “ Soil insect pests of peanut”…coming soon
      • “ Scouting techniques for soil insect pests of peanut”…review complete
    • Timely Information sheets: ( http://www.aces.edu/timelyinfo/entomology/entomology.php )
      • “ Germinating seed bait technique” (posted)
      • “ Peanut insecticide recommendations for 2009” (posted)
    • New peanut entomology SharePoint: https://sites.aces.edu/group/crops/peanut/default.aspx (PowerPoint shows with narration)
    • Conferences (like IPM-WC1, extension technology conf.)
    • YouTube Peanut Channel linked to ACES
    • CropsBlog: weekly updates in summer, PLEASE SUBSCRIBE!
  • 17. Take home message for today…
  • 18. SOIL INSECT PESTS OF PEANUT Questions?