By Dan Rahn
University of Georgia
The pesky insects damage turf grasses in the coastal plain and occasionally in piedmont areas of Georgia. They're active from early spring to late fall, he said. But they damage turf the most in late summer and early fall.
The best time to cancel their dinner reservations, Hudson said, is around the first week in July, when all of the season's eggs have hatched but the nymphs are still too small to do much damage.
"Mole crickets spend the winter mostly as adults in the soil," Hudson said. "As the weather warms, adults emerge and begin to feed and mate, beginning in March and continuing into May and June."
More mole cricketsMole crickets lay eggs in the soil, mostly in April and May. A single female may lay as many as six or eight clutches of about 40 eggs per clutch.
In three to six weeks, he said, the eggs hatch into nymphs that look much like adults but are smaller and don't have wings. Nymphs grow all summer and change into adults in the fall.
"Mole crickets damage turf both by tunneling and by feeding on the grass," Hudson said.
At low infestation levels, tunneling is probably the more damaging, he said, particularly in newly seeded areas.
With higher infestations, mole crickets will eat the grass and leave the soil pulverized and spongy to the step. Although adults can do considerable damage in the spring, the most serious injury usually comes from August to October, when the nymphs are large and active.
'Take that!'By late June or early July, though, all the eggs should have hatched into nymphs, he said. That's when an insecticide treatment can punch their little lunch tickets.
Homeowner insecticide options are limited. Products containing bifenthrin are effective if you apply them in June and July against small nymphs.
Products containing fipronil are effective, too. And they have a longer window of effective application - from early June through mid-July in most of Georgia's mole cricket infestations.
Irrigate before you apply insecticide sprays or granules if the soil is dry, Hudson said. Treat as late in the afternoon as you can, and water in sprays and granules with a quarter-inch of irrigation soon after application, unless the label advises otherwise.
Plan BAnother option is to treat them in fall or spring with insecticide baits. A number of commercial baits are available.
Baits are best used in the fall or spring, Hudson said, because they work better when the crickets are bigger.
"An advantage to baits is that you don't have to water them in," he said. For best results, apply baits near dusk.
You can find out how many mole crickets you have, he said, with a detergent solution. Dissolve 1 ounce of liquid detergent in 2 gallons of water and pour it over 1 square yard. Then count the number of mole crickets that emerge.
Repeat the process around the yard. A rule-of-thumb is that if you flush an average of more than five crickets per site, treat the lawn with an insecticide. But that can vary, Hudson said.
"It really depends on how healthy your lawn turf is and what demands you place on it," he said. "If you take really good care of it and just look at it, the turf can stand a lot of mole crickets and stay healthy."
(Dan Rahn is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)