Use of a beneficial nematode against pest mole crickets in Puerto Rico

A beneficial nematode, Steinemema scapterisci (Rhabditida: Steinernematidae), has been researched at the University of Florida and is now marketed as a biopesticide. Its primary target is the mole cricket, Scapteriscus vicinus Scudder (Orthoptera: Gryllotalpidae), which has been a pest in Florida for about 100 years. The nematode survives so well in Florida's sandy, low-organic soils that it serves as a classical biological control agent to provide permanent suppression of pest mole cricket populations in places to which it has spread. In Puerto Rico and islands of the Lesser Antilles, where there is a much wider range of soils, the primary mole cricket pest is Scapteriscus didactylus (Latreille). Our research evaluates the use of the nematode to control Scapteriscus didactylus. Our earlier results in the field showed establishment and survival for up to seven months in a sandy loam with mole crickets, but no establishment in a highly organic sandy soil with mole crickets. A laboratory bioassay in sterilized sand showed 100% survival of controls, but up to 100% mortality of mole crickets within 168 h dependent upon number of nematodes applied (dose or 'rate'). Laboratory survival of nematodes was poorer in non-sterilized soils than in sterilized soils.