Mole crickets are significant pests of turfgrass across the southeastern United States, causing substantial damage to lawns. These insects possess shovel-like front legs and tunnel just beneath the soil surface, uprooting grass and severing plant roots. This tunneling leads to irregular brown patches and a loose, spongy feel to the turf. Effective management requires timely cultural practices and targeted control methods.
Confirming the Infestation
The initial step in successful management is confirming the presence of mole crickets, as their damage can be mistaken for other issues like dry soil or disease. A primary sign of activity is the appearance of raised, ridge-like trails in the turf. The tunneling activity eventually causes the turf to feel spongy because the roots have been detached from the soil.
The most reliable confirmation technique is the “soap flush” or “soap test,” which forces the insects to the surface. To perform this, mix about two tablespoons of liquid dish soap into one gallon of water. Pour this solution evenly over a two-square-foot area where damage is suspected and observe the surface for several minutes.
If two to four mole crickets emerge within three minutes, treatment is warranted to prevent turf loss. This test is useful for monitoring populations and mapping areas that require attention. Identifying the specific location helps limit the use of control products to only the affected zones.
Understanding the Life Cycle for Effective Timing
The timing of control measures correlates directly with the vulnerability of the mole cricket’s life stage. Mole crickets undergo an incomplete life cycle (egg, nymph, adult), generally producing one generation per year. Adults emerge in the spring to mate and lay eggs in underground chambers, typically in clutches of 25 to 60.
Eggs typically hatch from late spring to early summer (late May to early July). The newly hatched nymphs are small, remain close to the soil surface, and are significantly more susceptible to control products. This early nymph stage is the most vulnerable point and the optimal window for applying treatments.
Applying insecticides later in the summer or fall is less effective because larger nymphs burrow deeper, making them more resistant to surface-applied products. Adults are also difficult to eliminate and often require higher insecticide rates. Success hinges on scouting for spring activity and timing applications to coincide with the peak egg hatch.
Chemical Control Strategies
Chemical control uses insecticides categorized as either curative or preventative. Preventative products, often containing imidacloprid or clothianidin, are applied early in the season. They target newly hatched nymphs with long-lasting residual effects and are highly effective when applied just before or at the beginning of the peak egg hatch in late spring.
Curative products, such as those containing bifenthrin or trichlorfon, provide a faster “knockdown.” They are used to treat active infestations of larger nymphs or adults later in the season. Fipronil is another highly effective active ingredient providing long-term control, often reserved for severe infestations due to cost. Alternating between different insecticide classes, like neonicotinoids and pyrethroids, helps prevent resistance development.
Proper application technique is essential for success. Granular and liquid insecticides must be watered into the soil immediately after application (one-quarter to one-half inch of irrigation). This moves the active ingredient into the root zone where the insects live. Bait formulations should be applied to moist soil in the late afternoon or evening, then left undisturbed and dry for two to three days, as moisture reduces effectiveness.
Non-Chemical and Biological Control Methods
Alternative approaches focus on biological agents and cultural practices that make the lawn less hospitable.
Biological Control
Beneficial nematodes, particularly Steinernema scapterisci, infect and kill the crickets. These microscopic worms carry a specialized bacterium that leads to the mole cricket’s death within a few days.
Nematodes are living organisms and must be applied correctly, requiring moist soil and protection from direct sunlight. They are typically applied at dawn or dusk and must be watered into the soil to ensure they reach the pests. S. scapterisci is most effective against larger nymphs and adults, meaning the application timing differs from chemical preventative treatments.
Cultural Practices
Cultural methods, such as improving soil drainage, reduce the appeal of an area to mole crickets, which prefer moist soil for egg-laying. Maintaining a healthy, dense turf through proper fertilization and watering allows the grass to recover quickly from feeding damage. Reducing outdoor light sources, such as porch lights, can also limit the number of adult crickets attracted to the property during spring mating flights.