Unlike other insects that attack plants from the outside, the Bermudagrass stem maggot damages them from inside, according to Dr. Vanessa Corriher-Olson, AgriLife Extension forage specialist, Overton.
"Basically, they consume material inside the stem, unlike armyworms or grasshoppers, where the damage is external," she said.
Corriher-Olson did her graduate work in Georgia, where the pest has had a presence since 2010, and she is familiar with the damage it does. The Van Zandt field is the first confirmed instance of the pest in Texas. She said the pest is native to southern Asia, common from Japan to Pakistan. Somehow it made its way to the U.S., where it was found in three Georgia counties.
"It’s relatively new to the U.S., and very little is known about its life cycle yet," Corriher-Olson said.
"It is not yet known how damaging this insect will be in Texas," said Dr. Allen Knutson, the AgriLife Extension entomologist at Dallas who confirmed the identity of larva found in a Van Zandt County field of irrigated Bermuda grass this summer.
What is known is infestation begins when the adult fly lays its eggs on a Bermuda grass stem near a node, Knutson said. The larvae, which grow to be about an eighth-inch long, look like a pale yellow maggot. They burrow into the Bermuda grass shoot to feed. This feeding causes the top two to three leaves to wither and die. Cutting open the stem just below these dead leaves will reveal the maggot and the brownish feeding site on the stem.
The adult flies may go unnoticed; they are small with dark eyes, Knutson said.
The early stages of an infestation may go unnoticed too, Corriher-Olson added.
To read more about the Bermudagrass stem maggot, click here for an article written by Robert Burns of Texas A&M.