Thrips
Frankliniella occidentalis (Western Flower Thrips)
Tiny slender insects that rasp and suck plant cells, leaving silver streaks on leaves. Several species transmit tomato spotted wilt virus.
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Identify from a photoBackground
Thrips are so small (1-2mm) and fast-moving they are often noticed only from their damage. They feed by rasping the leaf surface and sucking up the contents of the cells, producing characteristic silvery or bleached streaks dotted with tiny black frass specks. Western flower thrips and tomato thrips are also the primary vectors of tomato spotted wilt virus, a devastating disease of tomatoes, capsicums and many other crops.
How to identify
- Adults: 1-2mm, slender, yellow to dark brown, with fringed wings
- Larvae: similar shape, wingless, pale yellow
- Damage: silvery streaks and stippling on leaves and petals, flower distortion, black frass specks
- Tap a flower over white paper. Disturbed thrips will fall out
Life cycle
Egg to adult in 2-3 weeks at 25C. Females lay eggs inside plant tissue. Pupation occurs in soil or leaf litter. Continuous generations in warm weather.
Weather triggers
- Temperature: 12-35°C
- Thrive in warm dry weather. Heavy rain and high humidity suppress populations.
Peak season (southern hemisphere)
Red = active season · Dark red outlined = this month
Affected vegetables & crops
Click any crop to see current prices and growing info.
Climate zones at risk
Organic & low-impact control
- Blue sticky traps for monitoring and mass trapping
- Predatory mites (Neoseiulus cucumeris) in greenhouse situations
- Spinosad sprays targeted at flowers and growing tips
- Remove and destroy crop residues promptly
Chemical control
- Western flower thrips has broad resistance to synthetic insecticides
- Spinosad remains broadly effective but rotate with alternative modes of action
Always read product labels. Registrations change.
Prevention
- Inspect nursery seedlings carefully. Thrips and TSWV often arrive this way
- Weed control around crops (weeds host both thrips and viruses)
- Reflective silver mulch disrupts host-finding
Companion planting
Flowering insectary plants (alyssum, buckwheat, coriander) support predatory bugs and lacewings which take thrips.
Biosecurity
Western flower thrips is established in most states and is a declared pest in some horticultural regions.
Know when Thrips is actually about
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