Insect I.D.: April 2001, Mole Crickets

Seven species of mole crickets may be found in North American turfgrass, but only four of these are considered important pests. The tawny mole cricket and the southern mole cricket are the most damaging species. The short-winged mole cricket occurs occasionally at pest levels. Theses three species were introduced from South America. The native mole cricket is considered a nuisance pest in the northern part of its range.

Mole crickets that damage turf are found south of the line running from mid-North Carolina through mid-Louisiana and into southeastern Texas. Damage consistently occurs south of a line running from southeastern Texas along the Gulf States into southeastern North Carolina where southern grasses, such as centipedegrass, bahia-grass, Bermudagrass and St. Augustinegrass, are affected. The native mole cricket occurs throughout the eastern half of the United States. White the tawny and southern mole crickets are the most common and damaging pests, shortwinged and native species have also been known to cause damage in certain areas.

DIAGNOSIS. Mole crickets tunnel through soil like their mammal counterpart. This tunneling breaks up the soil around turf roots and the turfgrass often dies due to desiccation. Severe damage occurs in summer months when nymphs are actively feeding on turfgrass roots. Heavy infestations during this period may result in large dead patches and exposed soil. St. Augustinegrass does not show severe symptoms of damage from mole crickets, possibly because of its dense growth habit and fibrous root system.

GENERAL LIFE CYCLE & HABITS. Mole crickets undergo incomplete (gradual) metamorphosis with egg, nymph and adult stages. Nymphs resemble adults but are smaller and do not have developed wings. Most species have a single generation per year with adults maturing by fall, but do not lay eggs until the following spring.

IDENTIFICATION. Four common species of mole crickets can be identified by examining the claws (dactyls) on the front leg. The northern mole cricket has four major claws while the imported species have two. The space between the tibial dactyls, either V-shaped or U-shaped, separates the tawny mole cricket from the southern shortwinged.

Color patterns on the pronotum are also useful in separating species.