Cleyera – Wax Scale
Q: These white blobs are all over the cleyera hedge row in our yard. I don’t know what this is or how to treat it.
A: The blobs are wax scale insects. As with all scale insects, the adults you’ve noticed protect themselves with a waxy outer coating as they suck plant sap. Their red eggs are deposited under the wax coat. If you can physically remove all of the adults, that’s a good first step. Young wax scale, though, are camouflaged on plant stems. In late fall and winter, even the old standby horticultural oil (click for sources) will not suffocate many of them because they are not active in cold weather. Even so, a thorough spray with the oil now on a warm afternoon may kill some percentage of the insects.
The key to scale control is timing your spray to kill the crawlers just after they hatch from the eggs in April. Use carbaryl (click for sources) or spinosad (click for sources) three times, at two-week intervals, starting in mid-April to control the baby scale as they emerge from under the adults.