Thrips

Thrips — the most mobile pest of the six

Thrips are among the most frustrating pests because they are highly mobile and difficult to detect early. Unlike pests such as mealybugs or scale, which tend to stay in one place, thrips are active crawlers that can hop or fly between plants, letting infestations spread quickly. They feed by scraping the surface of leaves and sucking out plant sap — damaging the leaf tissue and disrupting healthy growth.

What to look out for

• Slender 'grain of rice' insects — Thrips are extremely small and slender, often appearing as dark or yellowish slivers on the leaves. They can look like tiny pieces of dust until they begin to move.
• Silvery streaks or patches — One of the clearest signs of thrips damage. As they scrape the leaf surface to feed, they leave behind shiny, silvery, or translucent patches on the foliage.
• Black specks — Tiny black dots may appear on the leaves — droppings left behind as the thrips feed.
• Distorted new growth — New leaves may come in twisted, stunted, or with brown scarred edges, from feeding damage done while the leaf was still developing.

Examples of thrips in real homes

Why they’re difficult to eliminate

Thrips have a life cycle that makes them particularly difficult to eliminate. They lay their eggs inside the leaf tissue, where many sprays cannot reach them. In another stage of the life cycle, the larvae drop into the soil to pupate — so the infestation can continue both on the foliage and in the soil.

How to treat them

1. Isolate immediately — Move the affected plant to a separate room to stop the infestation spreading to other plants.
2. Rinse the plant — Take it to the sink or shower and use a steady stream of water to wash away as many pests as possible. This removes many larvae and adults — but not the eggs inside the leaves.
3. Prune heavily infested areas — Remove heavily infested leaves or stems with clean scissors and dispose of them immediately. Because thrips are strongly attracted to pollen, remove any flowers too — they are a major breeding site.
4. Use an insecticide — Apply an insecticide thoroughly across the entire plant, including the stems and the undersides of leaves. Repeat weekly for about 5 weeks to break the pest life cycle.
5. Use a systemic treatment — Add a systemic insecticide to the soil so the plant absorbs it. When thrips feed on the plant's sap, they ingest the insecticide and die.
6. Use blue sticky traps — Place blue sticky traps near the affected plant to capture flying adults and help monitor the severity of the infestation.
7. Use a spinosad spray — Products containing spinosad — a naturally derived bacterium — are particularly effective against thrips and widely used in horticulture.