Home Gardening

Psocids cause needless panic for some
The Coast Gardener Newspaper and Web Column - September 22, 2001

Insect populations explode during the summer, and it's often a tedious task trying to keep track of which ones are good and which ones are bad. Calls have been pouring in to the Extension Office regarding silk webbing present on many tree trunks and branches all across the Gulf Coast. The initial sight of this webbing often evokes a sense of fear.

People often ask, "Is this going to kill my tree?" Have no fear! Small soft-bodied insects called psocids live under this webbing. They feed on algae, lichen, fungi, mold and other organic matter on the trunks and branches of trees.

These tiny insects, less that 1 inch long, are commonly called barklice or webspinners. The term barklice is somewhat misleading, because none of these insects are parasitic. Only a few species look similar to a louse.

Some species have wings whereas others are wingless. They also have fairly long antennae and utilize chewing mouthparts to obtain food. Psocids may lay eggs singly or in clusters.

One should not confuse psocids with fall webworms. As I discussed last week, fall webworms live in webbing among the leaves on trees such as oaks, persimmons and pecans. They can cause enough damage to kill limbs. Psocids, on the other hand, produce silken webs only on trunks and main tree branches. You will not likely find them among the leaves. I have seen the webbing start at the bottom and go all the way up the tree.

Nearly 150 species of psocids are found in the United States. Some of the species live in houses and buildings. These species are usually wingless and feed on starches in bookbindings. These species are commonly called booklice.

The majority of psocid species live outdoors. They have well-developed wings and are commonly found inhabiting the bark of trees and shrubs. Sometimes they are found underneath stones or similar materials. They generally live in very large clusters; therefore, it is common to see a whole mass of them move at once if they are disturbed.

Psocid invasions are at their peak during late summer. Sometimes they will hang around on trees through Halloween. They certainly add a bit of spooky decor to your landscape with their silk webbing. Try putting a spotlight on a tree wrapped up with them. What a ghostly sight!

Fortunately, they cause no harm whatsoever to trees. The are definitely a curiosity, but they present no real problems. Just enjoy their company for several weeks and they will be gone before you know it.

These archived gardening columns were written by Chance McDavid, former Harrison County Extension Agent.