Pest Scouting (Kutsvakana Nezvipukwana Mumunda)

By Mwazvita Zimunya

Importance of Scouting (Kukosha kwazvo)
Effective scouting gives an accurate estimate
of the pest levels in the field. Scouting helps
farmers determine:
• Pest abundance and diversity
• When to anticipate pest problems
• When to spray (Kunini lapho ongafafaza khona umuthi)
• What chemical to use
• If spraying has been effective
Timing of Scouting
• For vegetables, scout either 2 weeks after transplanting
• OR 8 weeks after direct seeding
• Scouting interval can be – 2 weekly OR fortnightly (amaviki amabili)
• Scouting interval depends on:

  • labour availability (varipo here vanhu vanokubatsira?)
  • crop value (zvimbori marii zvaurikutengesa?
  • target market requirements (vanotenga kwauri vanebasa nazvo here)
    Without scouting the following may happen:

Without scouting the following may happen:

  1. Spray when spraying is not required resulting in wastages (kutambisirwa mushonga)
  2. Delaying spraying when its required
  3. Using an incorrect pesticide for the pest present
    Steps in Scouting (Kuyenziwa njani?)
    Regardless of the crop, you have in the field, vaMudhumeni recommends the following steps to enable the effectiveness of the procedure
  4. Scout for whiteflies
  5. Scout for aphids, red spider mites
  6. Scout for bollworm eggs and larvae
  7. Scout for other pests
  8. Scout for predators and parasitoids

Steps in Scouting (Kuyenziwa njani?)
Regardless of the crop, you have in the field, vaMudhumeni recommends the following steps to enable the effectiveness of the procedure

  1. Scout for whiteflies
  2. Scout for aphids, red spider mites
  3. Scout for bollworm eggs and larvae
  4. Scout for other pests
  5. Scout for predators and parasitoids

Scouting Procedure
Use a chemical to spray the whole plant and collect all pests on a selection procedure:

• Randomly select a plant to get a representative sample
• Sample size depends on the size of the field (Generally take 24 plants/ha)
• Follow a zigzag or diagonal pattern across your field
• Leave at least 5m between sampled plants
• Avoid sampling field edges and sampling plants of the same row
• Don’t scout the same plant every week
• Avoid sampling very large small or large plants
Scouting for Specific Pests
• Pest abundance and diversity
• When to anticipate pest problems
• When to spray
• What chemical to use
Important
· During scouting, you may come across ladybugs. They are known for eating aphids, but they also eat other soft-bodied insect pests such as mealy bugs. These “beneficial” insects eat aphids, mites, caterpillars and other plant-consuming bugs and are harmless to people, plants and animals

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