Mole crickets cause damage in turfgrass by tunneling through the soil and feeding on the plant roots, stems and leaves. They push the dirt up, and if they are bad enough to kill grass, your lawn feels spongy when you walk on it.
If you suspect mole crickets but aren’t sure you have them, mix dishwashing detergent with water and pour it on those areas just before sunset. Soap will irritate them and make them come to the surface.
Some people might confuse mole cricket tunnels with earthworm mounds. Earthworms will have single, crusty mounds. No tunnels will be associated with them. Mole crickets make finger-width tunnels.
Understanding mole crickets’ life cycle will help you control them. Mole crickets spend the winter deep in the soil as adults or large nymphs (immature stage). Sometimes, when we have abnormally warm spells, they will come to the surface to feed. Those that over-winter as nymphs complete development and become adults in the spring, just in time for mating season. Mating takes place in late winter and early spring as the soil and air temperatures warm.
Both males and females fly on warm, humid nights, looking for mates or new areas to lay eggs. If you have been to a spring softball or baseball game at night, you might have seen their swarms. The times for these flights are anywhere from early April to early June. About 14 days after mating, the female lays an average of 35 to 40 eggs in the soil. Adults die after mating, so there are few left after June.
By late June and early July, all the eggs should be hatched. These baby mole crickets are at a point in their life when they are easiest to control with insecticides. The small crickets spend more time at or near the surface and are relatively easy to kill.
The size and extent of tunneling increases as the mole cricket ages. Early nymphs might live in an area of only a few square feet and cause very little noticeable damage. Couple that with thick grass, and most folks don’t even know they are there. In fact, it is not uncommon to find five to 10 nymphs per square foot with little or no turf injury.
However, as they get larger, they can tunnel over several yards and cause extensive injury. Golf courses will monitor sand traps when spring hatching begins, and also for the age of crickets based on tunnel size.
If control measures are not taken by late summer and early fall, the mole crickets are big again and much harder to kill.
Insecticides labeled for mole-cricket control for homeowners include bifenthrin and imidacloprid.
Bifenthrin is sold as a granular or liquid. Ortho Max Bug-B-Gon and Hi-Yield Bug Blaster are a couple of brand names.
Talstar is the commercial version of this insecticide. Imidacloprid is generally sold as Bayer Advanced Lawn – Season Long Grub Control or Complete Insect Killer. Bayer Complete Insect Killer will also be sold in granular or liquid form.
Whatever you choose, steps should be taken to maximize control. Mole crickets feed at night, so apply the insecticide just before dusk. If using a liquid, apply at least one gallon of solution per 1,000 square feet. Unless the label instructs otherwise, irrigate thoroughly after the application to move the insecticide off the foliage and down to the soil surface.
By irrigating, you can also manipulate the crickets to increase control. Allow the soil to dry out for three to four days (if that is possible with all the rain) and irrigate thoroughly the following evening. Apply the insecticide the next evening.
Mole crickets are sensitive to soil moisture and will move down in the ground to find comfortable conditions if the surface is dry. Watering will bring them back up to resume feeding the following night, thus making them easier targets for control.
Mole crickets prefer to feed on Bermudagrass lawns. They can cause damage on zoysia, St. Augustine or centipede, but that rarely occurs.