CultivaOS
Herbarium
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Thrips

Frankliniella occidentalis

PestLow impact

Minute slender insects that rasp the surface of leaves and flowers, leaving characteristic silvery streaking. Can also spread tomato spotted wilt virus in some situations. More common in warm, dry conditions.

Currently in peak season - extra vigilance worthwhile.

Key facts

Type
Pest
Affects
Bean · Cucumber · Basil
Active season
May - Sep
Peak season
Jul - Aug
Vulnerable stages
Growing · Harvesting
Spread rate
moderate
If confirmed
Act soon

Signs & symptoms

  • -silvery or pale streaking and scarring on leaf surfaces
  • -distorted or stunted new growth
  • -tiny slender insects (1-2mm) visible on foliage or in flowers
  • -white or silvery patches expanding as feeding progresses

Management

Do now

  • -Hang blue sticky traps near affected plants to monitor and reduce numbers
  • -Remove heavily damaged leaves and bin
  • -Raise humidity around plants - thrips prefer dry conditions

Prevention

  • -Maintain adequate humidity in growing areas, especially in polytunnels during hot spells
  • -Use biological control (Amblyseius cucumeris) in polytunnel situations
  • -Inspect plants regularly from early summer onwards

Further reading

  • -Thrips damage is typically cosmetic on established plants but can reduce crop quality
  • -They are harder to spot than aphids - look for the characteristic silvery streaking rather than the insect itself