Mole Crickets
Gryllotalpa & Scapteriscus spp., Gryllotalpidae, ORTHOPTERA


DESCRIPTION

Adult -- Covered with fine hairs which give it a velvety appearance, the 3.8 cm long, brown mole cricket has beady eyes and stout, shovel-like front legs for digging.

Egg -- The greenish, oval egg is about 3.2 mm long.

Nymphs -- Although wingless and slightly smaller, the nymphs resemble the adult in shape.


BIOLOGY

Distribution -- Thriving best in moist, light soils, mole crickets are common in Coastal Plain areas from North Carolina to Texas. They are particularly attracted to soil containing manure or rotting crop debris. Their vertical distribution in the soil varies with temperature and moisture.

Host Plants -- Although they have a wide host range, mole crickets are particularly damaging to the underground plant parts of vegetable crops, tobacco, peanuts, strawberries, and grasses. They are potential problems in seedling turfs and in established bahia grass.

Damage -- Burrowing in the soil, mole crickets feed at night on roots, stems, and tubers. The burrows cause the soil to dry out, thereby affecting plants that are not actually fed upon. Some plants may be uprooted, but turf usually dies from root damage and drought. Small numbers of mole crickets are capable of extensive damage, especially on newly seeded turf. One mole cricket may cover several meters (or several yards) each night. On golf greens, the raised tunnels made by mole crickets are skimmed off by the mower.

Life History -- Mole crickets generally overwinter as nymphs 7.5 to 25.0 cm (3 to 10 inches) deep in the soil. These nymphs become active in March and feed until they mature in late spring. In May or June, the new adults emerge from the soil and are attracted to lights as they engage in mating flights. Eggs are laid in the soil in cells constructed by the females. Approximately 35 to 50 eggs are placed in each cell. Hatching occurs in 10 to 40 days depending on temperature. Nymphs develop through 8 instars and may become adults by winter or may overwinter as immatures. One generation occurs each year.


CONTROL

Mole crickets are controlled with contact insecticides or poisoned baits. On established turf, spray or granular applications can be used as long as they are thoroughly watered into the grass. Such treatments will be most effective if they are applied when night temperatures are at least 15°C (about 60°F). However, as more pests migrate into the area, another application may be necessary. Poisoned baits are most effective in August or September when the young nymphs are hungry. For specific chemical controls, consult the state agricultural extension yervice recommendations.