Sycamore scale
4 host plants
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Sycamore scale appears as small, flat, grayish-brown encrusting scales clustered on bark of sycamore (Platanus) trees. Heavy infestations weaken branches and reduce tree vigor. Affected bark may exude honeydew, attracting ants and wasps. Most damaging in warmer regions; western Washington sycamores experience lighter infestations due to cooler temperatures.
Prune heavily infested branches in late winter to remove scale populations. Spray dormant horticultural oil in early spring before growth begins to smother overwintering scales. Do not over-fertilize, as soft growth favors scale reproduction. Preserve natural enemies, including parasitoid wasps and predatory beetles, by avoiding broad-spectrum pesticides.
Quick Reference
Cultural Controls
- biological control Larvae of green lacewings and other insects are aggressive predators of scale.
- A number of parasitic wasps will attack scale insects.
- However, biological control does not necessarily prevent significant scale infestations.
- Management-cultural control Scale can be rubbed off plants by hand with a glove or toothbrush.
- Major infestations can be pruned off.
- Tanglefoot, \"stickem,\" or a similar adhesive can be applied around infestations of adult scales to catch the crawler stage....