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Spider mites: some points to consider

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From the University of Minnesota Extension Southeast Crop Connection newsletter

spider mites

Spider mites are the concern today. Symptoms have become more obvious in some fields, especially along field edges, drought pockets and drier area in the region. Is this a "tornado watch" or "warning"? A watch in most fields, but we have touchdown (warning), with damage in some (more drought stressed conditions). You need to scout now. Here are some additional precautions and suggestions to consider.

  1. We are entering the critical time for soybean growth--pod set and fill, determining yield.
  2. When/If you pull the trigger and apply an insecticide now, this early in the season, plan on multiple application for multiple pests (aphids). You'll remove all beneficial insects and open the door to other pests.
  3. When making multiple applications it is imperative that you choose multiple modes of action.
  4. Canopy penetration is critical for good control.
    • Do not cheat on insecticide rates.
    • Do not cheat on water (gallons/acre applied).
    • Do not cheat on pressure--keep PSI up.
  5. Consider preharvest interval (PHI) when planning multiple applications of insecticides. Average range, 18-45 days. You may need to use a product with a longer PHI first followed by one with a different mode of action and a shorter PHI second.
  6. Insecticide/miticides will not kill spider mite eggs. Life cycle completed in 5-19 days (faster with temps above 90°)
  7. Remember buffer zones, and setbacks to sensitive areas for the insecticides you use. Read the label.
  8. Places to scout first: heaviest infestation usually occur along roadways, ditches, near alfalfa fields. Watch for spider mite movement from alfalfa to soybeans.

Read this article for more information on managing spider mites.

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