Thrips

Thrips are slender, fast-moving insects usually only 1-2mm long, so they're easily overlooked until damage appears. Adults are winged and range from pale yellow to dark brown or black depending on species, with narrow bodies and fringed wings held flat along the back when at rest. The immature nymphs are wingless, cream to pale yellow, and even smaller, often found clustered in the same tight spots as adults: inside flower buds, along leaf veins, and in the folds of new growth.

Thrips feed by rasping the surface of leaves, flowers and fruit and sucking up the sap that's released. This piercing action damages plant cells and leaves behind the characteristic silvery or bronzed scarring. Australia has many thrips species affecting home gardens, from western flower thrips and plague thrips to onion thrips and greenhouse thrips, each with slightly different host preferences but similar feeding habits and damage.

They're active year-round in warmer parts of Australia and become a bigger problem over spring and summer when populations build quickly in warm, dry weather. Thrips reproduce fast, with a new generation possible every two to three weeks in favourable conditions, and can move between plants on wind currents as well as by crawling and short flights.

Management relies on regular monitoring, since thrips hide in tight plant structures where sprays don't always reach well. Removing spent flowers and weeds that host thrips, encouraging predatory mites and lacewings, and using sticky traps to monitor adult activity all help keep numbers down. Heavy infestations or virus transmission may require targeted control at the right life stage.