Small dark specks on my houseplant: just a yellow leaf, or an unwanted visitor?

This looks like thrips, a common houseplant pest. The photograph shows a strongly yellowing leaf with small dark specks. As you also describe signs of pests, the overall picture fits damage from an infestation rather than natural ageing alone.

The dark specks are often droppings, and yellowing occurs as thrips feed on the leaf. An old leaf can of course yellow anyway, but these specks would make me treat the plant as affected now rather than wait.

What to do now

• Isolate the plant from other houseplants immediately.
• Remove this yellow leaf if it is clearly damaged.
• Rinse the whole plant, especially the undersides of the leaves.
• Then repeat treatment with a soap solution or a houseplant pest product, as thrips rarely disappear after a single treatment.
• Place blue or yellow sticky traps near the plant to check for more adult insects.
• Inspect nearby plants carefully, especially new growth and leaf undersides.

In September, when many houseplants still have a bright position but growth is slowing, damage often remains visible for longer and recovery is slower. Do not wait for more symptoms. If new leaves develop pale, scraped-looking areas or more black specks within one to two weeks, that confirms the infestation and means treatment needs to continue over several rounds.