BeneficialLettuce aphid
Hoverflies for lettuce aphid
Syrphidae · wild predator (larvae)
Against lettuce aphid
In organic romaine on California's Central Coast, syrphid larvae made up 85% or more of the predators in most trials and were the main reason heads infested early were largely aphid-free by harvest (Smith, Chaney & Bensen 2008). Romaine sprayed with spinosad, which suppressed them, was unsaleable. The aphid feeds deep in the heart of the plant. UC IPM notes syrphids cannot be bought from insectaries for the field; they must fly in, so the flowers bring them.
RateWild — intercrop with sweet alyssum, coriander, baby's breath or Persian clover (UC IPM)
TimingFrom the first aphids in young lettuce, before heads close
macro · hoverflies on lettuce aphid
The pestLettuce aphidNasonovia ribisnigriAphids packed into the heart of the head; contaminated, unsaleable lettuceFull pest profile →Before you act
The adults are the striped, hovering flies on open flowers; the larvae are legless, slug-like maggots that eat aphids inside the colony. How to recognise it, what it is confused with and how to keep it around are on the full Hoverflies profile.
Other controls for lettuce aphid
- Chrysoperla carneaGreen lacewing larvae · 2–20 /m² per release, weekly
- Aphelinus abdominalisParasitoid wasp · 0.25–4 /m² per release, repeated