It may take some gall to defend some of summer’s ugliest harbingers, but hear me out.

Reports are coming in of alien-looking growths on trees in yards and gardens across the Island. Landowners are concerned and curious about these galls, and interested in learning how to rid their property of the invaders. It may not be easy, but I know for sure that building a wall won’t keep these foreign bodies from getting in to the homeland.

Formed through the interaction of chemical stimuli and plant hormones, galls appear as swellings, growths and unusual pigmentation on leaves, stems and branches. These can sometimes be harmful to the plant host and sometimes not, depending on the species.

Galls are formed because of basic needs of organisms — food and shelter — being created though an ingenious method that provides both. Insects create most galls by injecting a compound that swells plant tissue. However, mites, fungi, bacteria and even viruses can also cause these growths. Two of the stranger-looking recent invaders are cedar apple rust and oak seed galls.

Orange and octopus-like describes cedar apple rust gall found on cedar trees. This condition is only a piece of the pie, since the presence of apple or crabapple trees is required to enable this phenomenon. Or, put another way, the fungus that causes cedar apple rust requires both apple or crabapple and cedar trees to complete its life cycle. It is quite a fascinating two-year dance between species, and quite a unique specialization of the fungus in question.

From orange, horned growths on cedar trees come fungus spores that are released in May and June, after the first warm rain. These airborne spores land on apple or crabapple trees and infect the leaves, giving them yellow, then orange or red spots. On the underside of the leaves, these spots develop into cluster cups, which then release more spores to infect the cedar (Juniper) species in June and July. At the end of the second year, galls will have formed on the twigs of the cedar. These galls mature and develop horns that release spores the coming spring. From there the cycle repeats.

While beautiful in its use of such a finely timed evolutionary mechanism, cedar apple rust can be destructive and disfiguring to trees. It will harm apple trees, though is less damaging to the cedar. Hawthorns and some ornamental junipers can also be affected.

The other alien growth that is currently being observed is the oak seed or wool sower gall. This one affects white oak trees and is caused by a small wasp in the Cynipid family. These swellings resemble cotton balls with pink spots, and sprout from white oaks. The wasp in question, fittingly called Callirhytis seminator, injects a chemical into the host tree that will produce a swelling to hold its progeny.

Those with a scientific mind or just natural curiosity can put wool sower gall in a sealed plastic bag, and after a few weeks find the one-to-three centimeter wasps that emerge from the seed-like structures within the gall. Be sure to keep the bag out of direct sunlight so you don’t have fried wasps.

These wasps lay eggs in the winter, which will hatch in the spring when the tree’s new leaves appear. This is another example of the exquisite timing of galls. Their presence is not known to harm the oaks, unlike their Cynipid cousins that are causing great losses of black oak tees Island-wide.

Each condition can be treated. In the case of the cedar apple rust, removing cedar trees within one mile of your apples can help, though this is not practical in most cases. Fungicides, pesticides and other ‘-cides’ are chemical control measures, though most who read this column will know those aren’t this author’s preferred method.

Perhaps we can just accept the melting pot of different shapes and colors produced by the influx of wasps and fungi. Henry David Thoreau accepted nature’s faults, asking: “Is not disease the rule of existence? There is not a lily pad floating on the river but has been riddled by insects. Almost every shrub and tree has its gall, oftentimes esteemed its chief ornament and hardly to be distinguished from the fruit. If misery loves company, misery has company enough. Now, at midsummer, find me a perfect leaf or fruit.”

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown, and author of Martha’s Vineyard: A Field Guide to Island Nature.