Thrips

What you see

Slender 1-2 mm slivers, straw to black, that scuttle sideways when disturbed. Easiest confirmation: shake a flower over white paper and watch for tiny running slivers.

Damage

Silvery-white streaking and speckling on leaves and petals, with minute black varnish dots of excrement. Distorted flowers, brown-edged petals, russeted onion and leek leaves.

Lifecycle on this coast

Very fast in warm dry weather, with several generations a season. Pupates in the soil, which is why soil-level control matters.

When to act

Cosmetic damage on foliage can be tolerated. Act when flower buds are distorting or on onions and leeks where silvering hits yield.

Months: May, June, July, August, September

Plants it bothers

Onion, Leek, Rose, Tomato, Sweet pepper, Cucumber, Strawberry

Natural enemies

Minute pirate bug, Predatory mite, Lacewing

Remedies

Yellow sticky traps, Insecticidal soap spray, Neem oil spray, Insect mesh and fleece barrier

The thing people get wrong

That silver sheen on onion and leek leaves that people put down to sun scorch or drought is nearly always thrips feeding scars. Look closely for the tiny black dots of excrement alongside the silvering - scorch has no dots, thrips always do.