Ladybugs for san jose scale
UC IPM names the twicestabbed lady beetle, Chilocorus orbus, among the predators of San Jose scale, but Washington State says biological control has not been adequate on its own, even in unsprayed orchards. Treat it as a partner to a dormant oil spray, which UC IPM rates low in toxicity to predators, rather than a replacement. Bought convergent lady beetles are aphid feeders and are the wrong insect for scale.
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 san jose scale
- Aphytis melinusParasitoid wasp · 5–10 per infested plant, or 5,000–10,000 per acre, every 1–3 weeks