We discussed leaf blisters in issue no. 6. Lately, we have received several samples of oaks with large brown spots, usually about the size of a quarter. These spots give a slight bulge, or bubble, to the leaf blade. It is not a new fungal disease. All cases have been confirmed as advanced stages of oak leaf blisters. The disease has been prevalent in 2002 but is not significantly harming trees. The lesions are initially light green and not very noticeable. As summer progresses, these spots often turn brown and draw more attention. Do not be too alarmed. Read our earlier article about this disease and relax.