Capsid bugs

What you are looking at

The newest leaves at the tips of the shoots are full of small holes. The holes are ragged rather than clean, each ringed with a narrow rim of dead brown or rusty tissue, and the leaf around them is puckered and lopsided as though it grew unevenly. Which is exactly what happened.

There is nothing on the plant. No caterpillar, no droppings, no slime, no webbing. That absence is the strongest clue in the whole diagnosis.

Dahlias and chrysanthemums show it worst, along with currants, gooseberries, fuchsias, roses and apples. On fruit it leaves small bumpy corky patches instead of holes.

The damage arrives after the insect has left

A capsid bug feeds by pushing its mouthparts into soft young tissue and injecting saliva that breaks the cells down so it can drink them. Each feeding puncture kills a pinhead of tissue in a leaf that is still tightly folded in the bud.

The leaf then grows. The living tissue expands and the dead spots cannot, so they tear, and each tear becomes a hole with a dead rim. The leaf ends up crumpled because it grew around a set of holes.

All of that takes a week or two, by which time the bug has moved on. That is why nobody ever finds the culprit, and why spraying the damage is pointless: the insect that caused it is somewhere else, quite possibly in another garden.

The bugs themselves are around 6 mm long, soft-bodied, green or straw-brown, with long antennae and long legs. They run fast, drop off at the slightest disturbance and fly readily. Early morning is the only time most people see one.

Why this page recommends doing nothing

The damage is superficial. The plant keeps growing, the holes do not spread, and a border that looked chewed in June looks perfectly normal by the middle of August.

There is no product available to gardeners that would help, and if there were, the timing problem would defeat it. What a spray would reliably do is kill the ladybirds, hoverfly larvae and predatory bugs sitting on the same foliage, and some capsids are themselves predators of aphids and mites.

The one exception is a plant grown for its flowers where the buds are being wrecked. Pinching out the worst shoot tips lets it break lower down and produce something worth cutting.

What to do about it

Confirm the diagnosis by the pattern rather than by finding the insect. Ragged brown-rimmed holes in the newest growth, with no frass and no slime, is this.

Pinch out badly damaged shoot tips on dahlias and chrysanthemums.

Clear weeds and dead stems from around affected plants over the winter.

Then leave it. The plant will outgrow it and so will you.

What it gets mistaken for

Caterpillars leave clean chewed edges, dry pellets of frass on the leaves below, and usually the caterpillar.

Slugs work at ground level on soft low growth at night and leave slime trails. Capsid damage is at the shoot tips, often at head height.

Flea beetles pepper brassica and rocket leaves with tiny round shot holes, without the brown rims and without distortion.

Sawfly larvae feed in groups from the outside of the leaf and are easy to find.

Mosaic viruses distort and pucker new leaves in a very similar way, and they mottle the tissue light and dark green rather than perforating it.

Frost damage on early growth browns whole leaf margins and shoot tips in one event, and it goes no further once the weather turns.