I have been finding the tips of branches underneath my trees that look like they have been chewed off. What is causing this? DK
The culprit is likely an insect called a Twig Girdler. Adults are longhorned beetles ranging from 1/2 to 5/8 inches in length. They are grayish brown with antennae typically at least as long as the body. The larvae are whitish, cylindrical, legless grubs that grow to about 3/4 inch in length.
Twig girdlers typically prefer pecan, hickory, persimmon, and elm. But, they will also enjoy oaks, honeylocust, hackberry, poplar, dogwood, and various fruit trees.
This time of year it is not unusual to see these chewed off branches on the ground around trees the twig girdlers call home. Preferred branches tend to be 1/4 to 1/2 an inch in diameter.
Adult twig girdlers emerge from late August to early October and begin to feed on the tender bark found near the branch ends. While feeding they find a mate and the female deposits their eggs underneath the bark.
There are typically 3 to 8 eggs deposited in each twig, but they may contain up to 40 eggs.
The females live around 6 to 10 weeks and repeat this process several times laying up to 200 eggs which begin to hatch in about 3 weeks.
Eggs cannot survive in a living twig, so the girdler chews almost all the way through the branch causing the branch to die. It then typically falls to the ground due to its weight or from the wind.
After hatching, the larvae overwinter in the dead twig feeding on the woody portion of the branch.
After a 12 to 14 day pupation period during August and September the following year, the adult chews a hole in the bark to escape and the process begins again.
It is not uncommon to see the ground almost covered with twigs in heavily infested trees. Young trees can take on a deformed appearance over the years due to a twig girdler infestation. This girdling not only affects the beauty of the tree but can also reduce yields in fruiting trees.
If you are finding these chewed off branches under your trees, your best strategy is to pick up those twigs and throw them away. This removes the insect from your yard and prevents the larvae from maturing and doing damage again next year.
You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at email@example.com.