What's Eating Your Coleus?

Tiny white moth-like insects, 1 to 2 mm long, that lift in a small cloud when you brush the foliage. Nymphs are flat translucent scales pasted to the underside of coleus's heart-shaped leaves. Both stages cluster on lower foliage, where humidity stays highest.

Lower leaves yellow and drop, and a sticky honeydew coats the leaves below the infestation. Sooty black mold follows, masking the variegated color patterns that make coleus worth growing. Heavy populations stunt the plant and can kill smaller specimens in a single season.

Small soft insects covered in a white waxy fluff that looks like cotton or lint. They cluster deep in the leaf-node junctions and along coleus's hollow square stems. Slow-moving and easy to miss against pale variegations, especially on white or cream cultivars.

Stems weaken at infested nodes and snap easily, and the leaves above the colony yellow and curl. Sticky honeydew coats lower foliage and draws sooty mold. Indoor coleus overwintered for spring cuttings is the most vulnerable.

Soft pear-shaped insects 2 to 3 mm long, in green, black, or grey, packed on the soft new shoot tips and flower spikes. They cluster on coleus's growing points where the leaves are still unfurling.

New leaves emerge twisted and stunted, often with a sticky honeydew coating that draws sooty mold. The plant pushes side shoots to compensate but loses the upright shape that makes coleus a good centerpiece. Aphids also vector mosaic viruses that distort future leaves.

Specks barely larger than a pinhead, in tan, red, or pale yellow, clustered on the underside of coleus's heart-shaped leaves. Fine webbing between leaves and along the stems is the giveaway. Hold a sheet of white paper under a tapped stem to confirm.

Leaves show pale stippling along the veins, then fade to a dusty bronze and drop. Indoor coleus near heat vents loses lower foliage in 2 to 3 weeks. The variegation patterns wash out before the leaves drop, so color loss is an early warning sign.

Soft-bodied brown or grey mollusks, 1 to 4 inches long, active overnight and on cool damp mornings. They hide under leaf litter, pot rims, and the underside of mulch by day. Look for silvery dried slime trails on stems and leaves at dawn.

Large ragged holes appear in coleus's soft leaves overnight, often eaten from the leaf edge inward. Whole young leaves vanish, and seedlings can be cut to the soil line. Damage is heaviest after rain and during the cool damp weeks of spring and autumn.