Rice Ipm Stout

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Dr. Michael Stout, LSU AgCenter Department of Entomology

* Integrated pest management in the rice system
* Incorporating new insecticides

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Rice Ipm Stout

  1. 1. Integrated pest management in the rice system Incorporating new insecticides Dr. Michael Stout, LSU AgCenter Department of Entomology E-mail: mstout@agcenter.lsu.edu 11:15 to noon
  2. 2. Insect pests of rice <ul><li>Early-season pests </li></ul><ul><li>Rice water weevil </li></ul><ul><li>Colaspis </li></ul><ul><li>South American rice miner </li></ul><ul><li>Aphids/chinch bugs </li></ul><ul><li>Armyworms </li></ul><ul><li>Late-season pests </li></ul><ul><li>Rice stink bug </li></ul><ul><li>Stem borers </li></ul>
  3. 3. The “drivers” of pest management decisions in rice Rice water weevil Rice stink bug
  4. 4. Insect pests of rice <ul><li>Early-season pests </li></ul><ul><li>Rice water weevil </li></ul><ul><li>Grape colaspis </li></ul><ul><li>South American rice miner </li></ul><ul><li>Aphids/chinch bugs </li></ul><ul><li>Armyworms </li></ul><ul><li>Late-season pests </li></ul><ul><li>Rice stink bug </li></ul><ul><li>Stem borers </li></ul>“ Proactive” approach! “ Reactive” approach!
  5. 5. Adult overwintering Larval feeding Mating and oviposition Adult feeding
  6. 6. Options for control of rice water weevils and other early-season pests <ul><li>Dermacor X-100 seed treatment </li></ul><ul><li>Cruiser Maxx seed treatment </li></ul><ul><li>Adulticidal pyrethroids: Karate, Mustang Max, Prolex, etc. </li></ul><ul><li>The seed treatments cannot be used in water-seeded rice!!!! </li></ul>
  7. 7. Is the use of seed treatments in Louisiana justified? <ul><li>More expensive – up to $20 per acre </li></ul><ul><li>“ Economic threshold” = density of weevil larvae at which benefits > costs </li></ul><ul><li>Yield loss from weevils: 0.5% - 1% per larva </li></ul><ul><li>For drill-seeded rice, ~3-5 larvae per core sample </li></ul><ul><li>In Dr. Hummel’s demo trials, 2009: 11/12 fields exceeded this threshold, 11 larvae per core average </li></ul><ul><li>The presence of other sporadic pests further justification </li></ul>
  8. 8. Q: Which of the seed treatments should you choose?
  9. 9. Q: Which of the seed treatments should you choose? A: it depends on which pests typically infest your fields
  10. 10. Spectrum of activity Cruiser Dermacor X-100
  11. 11. Spectrum of activity: what pests do they control? Dermacor X-100 Cruiser Maxx X Rice water weevil X Rice water weevil Colaspis X Colaspis X Stem borers Stem borers Sucking pests –chinch bugs, aphids X Sucking pests –chinch bugs, aphids X Other Leps – fall armwyorm Other Leps – fall armwyorm X South American Rice Miner South American Rice Miner
  12. 12. You might consider using Dermacor if… <ul><li>Field has a history of heavy weevil infestations or borer infestations </li></ul><ul><li>You are nervous about lack of data on Cruiser at low seeding rates or lack of commercial data for weevil efficacy </li></ul>
  13. 13. You might consider using Cruiser Maxx if… <ul><li>You think you may have problems with colaspis </li></ul><ul><li>You are worried about early-season diseases or early season sucking pests (chinch bugs & aphids) </li></ul>
  14. 14. What if you don’t use a seed treatment? <ul><li>Foliar (aerial) applications of pyrethroids the other choice </li></ul><ul><li>Pyrethroids cheaper, can be used in water-seeded rice </li></ul><ul><li>All of the pyrethroids are essentially equivalent </li></ul><ul><li>If any of the secondary/sporadic pests are present in the field, pyrethroids will kill </li></ul><ul><li>Scouting is necessary </li></ul>
  15. 15. Pyrethroids act by killing adults, thereby preventing egg-laying X
  16. 16. Timing of insecticide applications for weevil management <ul><li>Many adult weevils are present before flooding and additional weevils fly in after flooding </li></ul><ul><li>Females lay eggs in standing water </li></ul><ul><li>Females prefer young rice plants for egg-laying </li></ul><ul><li>Therefore, most egg-laying occurs shortly after flooding!!! </li></ul>
  17. 17. Apply pyrethroids when adults / feeding scars are present and fields are flooded A second application may be needed
  18. 18. Regardless of your choice of insecticides… Don’t put them in a position to fail!
  19. 19. Agronomic practices to minimize yield losses from weevils: <ul><li>Early planting (mid to late March?) </li></ul><ul><li>Avoid low seeding rates (e.g., 30 vs. 80) </li></ul><ul><li>Delay flood until rice is in mid-tillering (e.g, 42 vs 28 d after planting) </li></ul><ul><li>Keep water depth shallow (e.g., 2” vs. 6”) </li></ul><ul><li>Avoid high rates of N fertilization </li></ul>
  20. 21. 18% 39%
  21. 22. Tolerance is dependent on plant age… Zou et al., Crop Protect. 23: 543 (2004) 0 10 20 30 40 50 60 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 No. of immatures per core, 20 daf Standardized yield Flooded 28 d after seeding Flooded 42 d after seeding
  22. 23. What about crawfish? <ul><li>All insecticides have wording on their labels prohibiting crawfish culture in rice fields in which the insecticides are used </li></ul><ul><li>What about drift and run-off into ponds? </li></ul><ul><li>New insecticides are less acutely toxic to crawfish than pyrethroids </li></ul>
  23. 24. The “drivers” of pest management decisions in rice Rice water weevil Rice stink bug
  24. 29. Rice Stink Bug Damage Feeding on flowers (non-filled seed ) Remove contents of developing kernels (partially-filled seed) Pecky rice and broken kernels Photograph by Boris Castro Photograph by Boris Castro
  25. 30. Rice stink bug management <ul><li>Adults can move into fields rapidly after heading </li></ul><ul><li>Adults are the primary damaging stage </li></ul><ul><li>Thresholds are important – mere presence of stink bugs in a field should not trigger spraying </li></ul><ul><li>Scout with sweep net </li></ul><ul><li>What about natural enemies? </li></ul>
  26. 31. Scouting and thresholds <ul><li>Begin scouting when rice is 50 to 75% heading </li></ul><ul><li>10 sweeps at 10 different areas </li></ul><ul><li>Avoid hot hours </li></ul><ul><li>First two weeks of heading: 3 bugs per 10 sweeps </li></ul><ul><li>After first two weeks: 10 bugs per 10 sweeps </li></ul><ul><li>Treatments: methyl parathion, malathion (not recommended), and pyrethroids </li></ul>
  27. 32. Sugarcane borer
  28. 42. Stem borer management <ul><li>Scouting begins at green ring, intensifies as early boot approaches </li></ul><ul><li>Look for adults, egg masses, or feeding lesions </li></ul><ul><li>No thresholds yet, insecticides targeted at adults </li></ul><ul><li>Pyrethroids </li></ul><ul><li>Dermacor has activity </li></ul>
  29. 43. Management of Sugarcane Borer Infestations in Rice Using Selected Rates of Insecticides, Louisiana 2004

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