I received several images of white oak leaves from a homeowner who wanted to know why the leaves appeared bleached. The culprit was Oak Lace Bug (Corythucha arcuata). This lace bug lives on the undersides of oak leaves where they use their piercing/sucking mouth parts to suck juices from the leaves. As with all lace bugs, their feeding produces tiny yellow or whitish leaf spots (stippling) that may coalesce to produce large, white patches on the upper leaf surface. Eventually, the damage becomes yellow-to-copper colored and the overall damage can produce early leaf drop.
The lace bugs also deposit unsightly tar-like spots of excrement onto the lower leaf surface as they feed. As with most lace bugs, the oak lace bug has multiple generations per season; their damage builds with each succeeding crop of new bugs.