Cost effectiveness of biological control of invasive mole crickets in Florida pastures

Abstract

The Mole Cricket Biological Control Program (MCBCP) is a compelling example of successfully managing alien invasive pests that warrants formal analysis and documentation of its effectiveness and benefits relative to costs for cattlemen in the southeastern U.S. Three biological control agents that parasitize the short-winged mole cricket, Neoscapteriscus abbreviatus (Scudder); tawny mole cricket, Neoscapteriscus vicinus (Scudder); and southern mole cricket, Neoscapteriscus borellii (Giglio-Tos) (Orthoptera: Gryllotalpidae) were imported from the origin of the pests in South America, tested for non-target affects, and distributed widely in Florida. Larra bicolor F. (Hymenoptera: Crabronidae), a parasitoid of large nymph and adult mole crickets, was collected in Bolivia and established in Florida in 1988–89, and later in Georgia, Alabama, and Mississippi. Another parasitoid of large mole crickets, Ormia depleta (Wiedemann) (Diptera: Tachinidae), was introduced several times from Brazil during the early 1980s and released extensively. An entomopathogenic nematode discovered in Uruguay, Steinernema scapterisci (Nematoda: Rhabditida: Steinernematidae) reproduces within adult mole crickets, building up large populations that infect additional mole crickets and ultimately creates an epidemic. This very effective biological control agent was applied to pastures, turf farms, golf courses, athletic fields, and other mole cricket habitats across Florida after in vitro culture was developed and a commercial product, “Nematac® S,” became available. During the 34years of the MCBCP (1979–2012), about $8.7million was spent on faculty salaries and operating costs and the overall annual savings in control costs was estimated to be $13.6million; a first year benefit-cost ratio of 1.6:1. Applying a 3% social discount rate (perpetual benefit), the MCBCP will save cattle producers $453million for a long-term benefit-cost ratio of 52:1.