Beauveria bassiana for greenhouse whitefly
On the label for greenhouse whitefly, and a standard greenhouse option. UMass and UConn both stress that sprays must start while numbers are still low, and the label expects control 7–10 days after the first spray. It only kills what it touches, so cover the undersides of infested leaves. Infected nymphs turn brown or pink. On crops that stay in for five months or more, UMass says Encarsia formosa releases work better.
Before you order
Spores of an insect-killing fungus, sprayed on to the pest. They stick, germinate and grow through the insect's skin, so coverage is everything. It is slow, working over 7–10 days, and must start while numbers are low. It can also infect some beneficial insects. How it works, how to tell it has established and the supplier list are on the full Beauveria bassiana strain GHA profile.
Other controls for greenhouse whitefly
- Encarsia formosaWhitefly parasitoid · 1–10 /m² per release, weekly until control is achieved
- Amblyseius swirskiiPredatory mite · 25–100 /m² per release (UF/IFAS range), or sachets
- Eretmocerus eremicusWhitefly parasitoid · 1–10 /m² per release, weekly
- Delphastus catalinaePredatory ladybird · 10 per infested plant or 100 per hot spot, weekly for 3–4 weeks
- Big-eyed bugsWild predator · wild, attract it
- Dicyphus hesperusPredatory bug · 500 per acre (Arbico); a Canadian trial released 1.25 adults per plant, three weeks after the whitefly