ESTABLISHMENT AND PERSISTENCE OF STEINERNEMA-SCAPTERISCI (RHABDITIDA,STEINERNEMATIDAE) IN FIELD POPULATIONS OF SCAPTERISCUS SPP MOLE CRICKETS (ORTHOPTERA, GRYLLOTALPIDAE)

The first successful inoculative releases of an entomopathogenic nemat ode, Steinernema scapterisci Nguyen and Smart, for the control of exot ic pests, Scapteriscus spp. mole crickets, were made at three pasture sites in Alachua County, Florida in 1985. Based on the evaluation of f ield-collected crickets, the nematode was established at all sites and persisted for over 5 years. Mean yearly percentage of infected cricke ts ranged from 0 to 21.4% for individual release sites. Mean adult inf ection level for all years combined, 10.9%, was significantly greater than that for nymphs (2.5%) and infection levels for Scapteriscus bore llii Giglio-Tos, 12.7%, was significantly greater than that for Scapte riscus vicinus Scudder (4.5%) for all years combined. Although 24 h tr ap catch results indicate mole cricket populations were significantly reduced, the nematode's effect on pest abundance could not be adequate ly assessed because of the variation in trap catch results and inadequ ate knowledge about the relationship between trap catch and the mole c ricket field populations being sampled. Despite inadequacies in estima ting pest abundance, the results indicate S. scapterisci has potential as a biological control agent for pest mole crickets in the genus Sca pteriscus.