Fruit trees are an investment in both time and money, so it’s understandable when folks get troubled by unknown growths in those. I’ll often get questions about scaley, greenish-blue things attached to the trunk. This usually turns out to be a lichen. A lichen is a fungus and an algae living symbiotically, where the fungus provides the structure and the algae provides the photosynthesis. They come in lots of different forms, from moss-like growths hanging from the limbs to those patches in various textures and colors on the bark.
The good news is that lichens — in and of themselves — are essentially harmless to your fruit trees. They can signal a couple of conditions, though: 1) Your air is clean. Lichens can’t tolerate air pollution, so they’re not as common around big cities and industrial sites as they are in a rural orchard; 2) Your tree’s growth has slowed down. Lichens aren’t able to become established to fast-growing trees, so if you have lichens, either the tree has reached maturity, or possibly some nutritional issue or other soil condition has slowed its development.
But the bottom line is that the lichens themselves don’t require treatment. Just admire them and be grateful for your clean air.
Another oddity that SHOULD cause concern, however, is this creature:
I was driving along a farm road in Southwest Virginia a couple of weeks ago, right after a rain, and the eastern redcedars along the fenceline were full of these Tennessee-orange, squid-like blobs. As spring progresses, the “tentacles” will dry up, leaving a gall in the tree that looks like a potato. This is the redcedar-phase of a fungal pathogen called cedar-apple rust. If you have redcedar trees near your orchard and they’re full of these, you can expect rust disease in your apples later in the summer. The most obvious fix is to remove the redcedars, but if that isn’t practical, then you’ll need to plan a preventative fungicide treatment for your apple trees. There are some organic options. Consult your local Extension office for details.
For the record, our eastern redcedars are technically junipers and not true cedars, so if you have junipers in your landscaping, they can also serve as a spring host for the pathogen.