Other Problems - Lichens

SYMPTOMS

Gray-green scaly growth on trunk, branches, or twigs.

DESCRIPTION OF PEST

Lichens are a complex organism consisting of a fungus and an alga that have a relationship for mutual benefit (symbiotic). There are several different forms that the body of the lichen (thallus) will look like. Foliose forms are three-dimensional, lobed, and leafy in appearance. Fruticose are highly branched and three-dimensional, looking somewhat like a miniature shrub. Crustose are flattened and scaly, being tightly attached to the bark. Squamulose are somewhat flattened, overlapping lobes that look similar to foliose, but are not as three-dimensional.

Lichens are not plant parasites. They require only a sunny spot to grow. Lichens can be found growing on fences, rocks, brick walls, and directly on the ground. When lichens appear on dead branches of plants, it is not the lichens that killed the branches; they are just taking advantage of a sunny location to grow.

foliose form

A foliose form of lichen growing on a branch.

MANAGEMENT

CHEMICAL
Chemical control is not necessary.

BIOLOGICAL

Managing plants for better health will cause more foliage which will shade out the areas that lichens have colonized.

fruticose

A fruticose form of lichen growing on a branch.
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