Tarnished plant bug
Lygus lineolaris
also called Lygus bug
A quick, mottled bronze bug whose feeding kills the growing point and deforms fruit. It is behind more misshapen strawberries and blind shoots than anything else.
How to know it
An oval bug 5–6 mm long, mottled brown, bronze and cream with a small pale triangle behind the shoulders, that runs sideways and drops or flies the moment you approach. The nymphs are yellow-green with five black dots on the back and are easily mistaken for aphids until they move — much faster.
What you'll see
- Strawberries that are nubbly, hard and seedy at the tip — cat-faced fruit — with the rest of the berry sound.
- Shoot tips blackened and dead, and plants branching sideways from below the kill.
- Flower buds dropping before opening, and blind shoots that never flower.
- Small sunken brown spots on leaves and stems where the bug has fed, sometimes tearing into holes as the leaf expands.
- Distorted, puckered new leaves on dahlias, asters and chrysanthemums.
Where it comes from
Adults overwinter under leaf litter, in hedgerows and among weeds, and come out very early in spring. They feed on weed flowers first, then move into the garden. Three to five generations a year, and the migration into crops usually follows the mowing or drying of a nearby weedy field or verge.
Gardens next to rough ground, verges and hayfields take the worst of it, and damage spikes within days of that ground being cut. Warm springs bring the first generation forward.
Dealing with it
- Hand-pick into a jar in the very early morning, when the bugs are cold and slow — this is the only time you will catch them.
- Cover strawberries with fine mesh from first flower until the fruit is set.
- Spray insecticidal soap onto nymphs early in the morning; adults are almost impossible to hit.
- Do not mow the rough ground next to the garden during flowering — you will drive the whole population into your crops.
- Keep a flowering strip of alfalfa or vetch as a trap crop and mow it in strips rather than all at once.
Keeping it out
- Keep the garden edges weed-free through spring, particularly of dandelion, shepherd purse and chickweed.
- Mesh strawberries and prize flowers through the flowering period.
- Clear leaf litter and old growth at the boundary in late autumn.
- Grow flowering umbels for the big-eyed bugs, damsel bugs and parasitic wasps that hunt it.
- Plan mowing of the surrounding ground for after the strawberries have set.
What it goes for
Strawberries above all, then dahlias, asters, chrysanthemums, beans, lettuce, celery and peaches.
Who hunts it for you
- Damsel bugNabidae A slender, mantis-armed bug that grabs aphids, small caterpillars, and thrips in low crops and meadowy edges. Leave a strip of unmown grasses and flowers for it to overwinter in. Grow to recruit it: Fennel,Sweet alyssum,Yarrow
- Parasitic waspsBraconidae & Trichogramma Tiny, stingless wasps that lay eggs in or on caterpillars, aphids, and moth eggs — the white cocoons riding a hornworm are their calling card, so leave that caterpillar be. Umbel flowers with shallow nectar keep the adults fuelled. Grow to recruit it: Cilantro,Dill,Fennel,Lovage,Parsley,Sweet alyssum
See also
The Cottage Garden Companion — the gardener's bestiary at cottagegardencompanion.com