Ladybugs for black bean aphid
The RHS lists ladybirds among the natural enemies of blackfly in gardens. Colonies are usually tended by ants, which the RHS says remove predators such as ladybird larvae, so ant control helps more than buying beetles. Tolerate the early colonies; the larvae arrive where aphids are plentiful.
Before you act
Everyone's first idea for aphids, and the one beneficial where buying is usually the wrong move. The ladybugs sold by the tub are convergent lady beetles collected from the wild, and UC IPM says most fly away within a day or two of release, even when aphids are plentiful. The larvae do much of the eating, and they turn up on their own wherever there are aphids. How to recognise it, what it is confused with and how to keep it around are on the full Ladybugs profile.
Other controls for black bean aphid
- HoverfliesWild predator (larvae) · Wild — attract adults with open flowers
- Aphidoletes aphidimyzaPredatory midge · 1–10 /m² per release, weekly
- Chrysoperla carneaGreen lacewing larvae · 2–20 /m² per release, weekly
- Aphidius colemaniParasitoid wasp · 0.25–4 /m² per release, under glass only