I just noticed recently my apple tree has dark brown blisters on the bark. All are about 4-5mm in diameter. I picked off several, most have a dry yellow granule inside. A few had yellow goop inside. Could this be a bug? The bark under these blisters is damaged and in some cases missing. Anyone know what it is and what can be done? Thanks
They're probably scale insects. Check them out on Google; there are lots of ways to get rid of them. If they aren't numerous, picking them off should be sufficient.
