Which Mole Crickets Are Pests

Introduction

Damage caused by mole crickets to plants is mainly by feeding, but in part by tunnelling. Feeding occurs underground on roots, at any time of day or night. At night, in warm, wet weather, mole crickets also will feed at ground-surface level on stems and leaves of plants; they do not climb above ground level. Their propensity to cut the stems of seedling vegetables, leaving the top of the plant and the roots undamaged, but killing the plant, is especially damaging. By tunnelling, they disturb roots of plants, and drought-stressed plants are less tolerant to disturbance. Finally, galleries (i.e., horizontal tunnels only just below the ground surface, and causing soil to bulge above the surface) spoil the smooth surface of golf course greens.

Mole crickets eat turf- and pasture-grasses and many other plants. All commonly-grown turf- and pasture-grasses in Florida are susceptible to them. In general among grass species, bahiagrass is damaged heavily, closely followed by Bermudagrasses, whereas St. Augustinegrass, zoysiagrasses, and centipedegrass suffer less damage. Selected cultivars within these grass species may exhibit more or less damage than is typical of the species. Some grass species (and cultivars) seem to be preferred, which means that mole crickets, when given a choice, will more readily feed on one grass species than on another. Given no choice, then they will feed on whatever grass is available. Some grasses suffer less damage when exposed to equal numbers of mole crickets, which means that feeding and tunnelling by mole crickets has less effect on these due to their growth characteristics.

Mole crickets have been known to attack tomatoes, sweet-peppers, egg plants, carrots, potatoes, sweet-potatoes, cabbage, and peanuts. They also attack tobacco seedlings.

Mole Crickets As Pests

There are several reasons why mole crickets are important pests. First, most of the species mentioned in this knowledgebase are immigrants and, when they arrived, had no specific natural enemies, which were left behind in their homelands. This situation is being corrected by biological control research. Second, soils in some areas (e.g., the coastal plains of the southeastern USA) provide ideal conditions for some of them, because these soils are very light and easy for Scapteriscus spp. to tunnel in. Third, humans planted a smorgasbord of their preferred foods, including about 4.4 million acres of Bahiagrass in Florida alone. By sheer carelessness, humans planted this immense area of the preferred food of Scapteriscus mole crickets (bahiagrass, from South America) and simultaneously provided the means (ballast of ships) by which Scapteriscus mole crickets (from South America) hitchhiked to find this preferred food. How could one ask for a better recipe for trouble?

Pest Status of Mole Crickets

NATIVE SPECIES

northern mole cricket: rarely, if ever, a pest in America north of Mexico

western mole cricket: not a pest

prairie mole cricket: not a pest

IMMIGRANT SPECIES

European mole cricket: at most a minor pest in the USA; now rare in some western European countries

oriental mole cricket: has been recorded as damaging irrigation dikes (by tunnelling) and sugarcane; status in Hawaiian turf needs clarification

shortwinged mole cricket: a pest of vegetable seedlings and turf

southern mole cricket: damages turf and pasture grasses, mainly by tunnelling (because it is largely carnivorous)

West Indian mole cricket: a major pest of vegetable seedlings and turf

imitator mole cricket: probably a pest in Puerto Rico, but level of damage caused by it has not been distinguished clearly from damage caused by West Indian mole crickets

tawny mole cricket: a major pest of vegetable seedlings, turf and pasture grasses


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