We live in an oak forested area. The entire neighborhood is experiencing a terrible infestation of scale insects - so much so that other plants, driveways, patios, streets are covered with the sticky substance that these insects emit. Is there anything that can be done? Our oaks are 50+ years old, so they are quite large and I would imagine hard to treat. We might be able to treat some of the smaller trees - redbud for instance, but won't they just be re-infested if we don't treat all the trees?