Trees are a major part of any landscape.

But when leaves begin to turn brown and die, gardeners often become alarmed. The tips of branches on many Lawrence trees aren’t doing well. Botryosphaeria canker and twig girdlers, which look similar, cause branches to turn brown or make the tips of branches fall off.

Pin oak and other red oak trees infected with the Botryosphaeria fungus exhibit a wilting or “flagging” of twigs or small branches throughout the tree. Fully developed leaves on the twigs initially bend back toward the twig and then turn brown. The dieback extends 4 to 6 inches down the twig, and the orange-brown leaves remain attached.

The dead twig turns black and may develop cracks. The line between dead and live stem tissue is very noticeable. To see this transition, take a knife and carefully scrape away the outer bark layer. Healthy bark will be light green, whereas diseased bark will be dark brown to black. The Botryosphaeria fungus tends to cause more damage to stressed plants.

Twig dieback rarely progresses more than a couple of inches down the twig and usually does not continue the following year. As a result chemical controls are not recommended. Dead twigs can be removed on small trees, but otherwise do not bother.

The second cause for twig death is an insect called a twig girdler. They attack elm, hickory, oak, linden, hackberry, apple, pecan, persimmon, poplar, sour gum, honeylocust, dogwood and some flowering fruit trees. Their damage appears as dead twigs that eventually fall from the tree. The adults are long-horned beetles with a grayish-brown body that is stout and cylindrical. The larvae have a small head, are 1 inch in length and are light brown to brownish-gray.

The beetle has a one-year life cycle. Late in the growing season, the female deposits eggs in small wounds chewed through the bark. She then chews a continuous band around the twig — girdling it. Girdled twigs die and fall to the ground. The outside of the twig is smoothly cut, but the center of the twig has a broken appearance. Once on the ground, the egg hatches and the larvae begin feeding on the dead wood inside. This feeding continues through most of the following summer. In August, the larvae pupates into adults and emerge to repeat the cycle.

Though the girdling is unsightly, it does not effect the overall health of the tree. Likewise, because of the insects’ life cycle, chemical control is impractical. Fallen twigs should be gathered and disposed of in the fall or spring to destroy the larvae inside. Often, mortality is high due to excessive drying of fallen twigs or too many larvae per twig.