Pest watch: thrips (October 2025)
14 November 2025
Common, tiny pests capable of causing big damage
Despite ranging from the size of a sugar granule to a grain of rice, thrips (Thysanoptera) can cause significant losses for Australian production nurseries. Thrips are a common pest in the greenlife sector, characterised by their tiny cigar-shaped bodies that often infest plants in swarms, damaging everything from field crops to vegetable seedlings, potted colour to ornamentals.
Every grower has encountered thrips, but the broad variety of species means no single treatment will reliably control an infestation.
Wait, how many species?
Around 1,000 species have been identified in Australia, with more than 5,000 recognised globally (CSIRO). This diversity matters: different species vary in their susceptibility to chemicals and in their ability to transmit viruses such as tomato spotted wilt virus and impatiens necrotic spot virus.
Recognising thrip damage
Given the size of thrips, growers are likely to identify an infestation once a plant is already showing signs of distress. Symptoms in once healthy plants include:
| Older leaves | New growth |
|---|---|
| Relatively mild damage, including formation of silvery patches that turn brown as the cell tissues dry up beneath the epidermis. | Feeding damage on new growth develops: • leaf distortion • leaf scarring • petal scarring • leaf drop • rind blemishes |
Preventing infestations before they start
Because thrips are small and mobile, early detection is critical. The following measures can help reduce risk.
| Monitoring pest populations regularly, particularly in high-risk seasons and crops | Managing weeds and cross-contamination | Propagating from pest free mother stock | Growing in protected cropping environments | |
|---|---|---|---|---|
| Research has linked thrips activity to warm, dry conditions. During these periods, inspect new flush and flower tissues several times a week. Blue or yellow sticky traps are useful for detecting emerging populations early. | Thrips are typical ‘hitchhiker’ pests, moving between sites on contaminated plant material, soil and equipment. Keep new stock isolated and inspect carefully before introducing it to production areas. Remain vigilant and maintain strict hygiene across tools, benches and transport vehicles. | Thrips feed by sucking sap from plants, and infested mother stock can spread the pest through cuttings. Only use clean, thrip-free material for propagation, and monitor source plants regularly for signs of activity. | Maintain a hygienic, well-controlled nursery environment aligned with your production plan. Implement strict sanitation and exclusion practices to minimise pest entry. Use biocontrol agents or registered pesticides where necessary for immediate suppression. |
Suspected infection? Next steps
For detailed guidance, see the new thrips management plan.
All production nurseries receive six free samples annually with Grow Help. If you need a species of thrips identified, this can be requested online. Resources are also available via the Pest ID tool.
