Pests, webbing, and leaf spots on moth orchid

How to tell

Small, brown, limpet-like bumps stuck to stems and the undersides of leaves, often with sticky honeydew.

The fix

Scrape them off gently with a fingernail or old toothbrush, then treat with a neem or horticultural-oil product made for houseplants, as its label directs, and keep checking. Test the spray on one leaf and wait two days before treating the whole plant, and skip any plant the label warns against.

How to get rid of scale →

How to tell

Fine webbing in the leaf joints, tiny moving dots, and a stippled, dusty look to the leaves. They thrive in the dry air many homes have.

The fix

Wipe the leaves with a damp cotton pad, keeping water out of the crown, and treat with an insecticidal soap or neem product made for houseplants, repeating as its label directs until they are gone. Test the spray on one leaf and wait two days before treating the whole plant, and skip any plant the label warns against. Isolate it from other plants.

How to get rid of spider mites →

How to tell

Silvery, shiny patches on the leaves, dotted with tiny black specks of droppings that wipe off. The insects are slim, 1 to 2 mm long, and run or drop when disturbed.

The fix

Isolate the plant and remove badly damaged flowers or leaves. Avoid soaking the foliage or crown. Use only a thrips treatment labelled for this plant, follow its instructions and test a small area first. If leaves get wet, dry them promptly. Depending on the species, non-feeding stages shelter in the potting medium, plant crevices or on leaves. Sticky cards monitor flying adults. Keep checking for several weeks.

How to get rid of thrips →

How to tell

Soft, translucent, or black-edged spots on leaves, often after water sat in the crown or on the leaves.

The fix

Remove affected tissue with a clean blade, keep water off the crown and leaves entirely, and improve airflow around the plant.

How to tell

Dry, bleached, or brown patches only where strong direct sun hits the leaf, with no bugs or webbing. Moth orchid wants bright, indirect light.

The fix

Move it back from the glass, out of the strongest sun.