Steinernema scapterisci as a Biological Control Agent of Scapteriscus Mole Crickets

Abstract

Scapteriscus didactylus, Sc. abbreviatus, Sc. borellii and Sc. vicinus are South American mole crickets (Orthoptera: Gryllotalpidae) that have arrived in the Caribbean and the southeastern United States, where they have become pests of turf- and pasture-grasses, vegetable seedlings and other crops. All four species have been targets of classical biological control. Three classical biological control agents have been introduced and established against them. A wasp, Larra bicolor (Hymenoptera: Sphecidae), was introduced into Puerto Rico in the late 1930s, and decades later into Florida, whence it spread to Georgia and Mississippi. A nematode, Steinernema scapterisci (Nematoda: Steinernematidae), was introduced into Florida in 1985 and into Puerto Rico in 2001. A fly, Ormia depleta (Diptera: Tachinidae), was introduced into Florida in 1988. Steinernema scapterisci has been mass-produced on artificial diets and marketed as a biopesticide with a difference, in that it can establish permanent populations in sandy, low-organic soils with Scapteriscus mole crickets. As such, it can readily be deployed where its services are needed. It is highly specialized to the genus Scapteriscus, without non-target effects, and it is highly tolerant of chemical insecticides, thus adapted for use in integrated pest management strategies. It functions well against Scapteriscus adults (just like the other two biological control agents), but has limited effect against nymphs.