Inoculative Biological Control of Mole Crickets
Six species of mole crickets have become pests in parts of the U.S. (including Hawaii) and its Caribbean territories (Puerto Rico and the U.S. Virgin Islands). All are of exotic origin and arrived without the specialist natural enemies that help to keep them in check in their homelands. They can be killed with chemical pesticides, but the cost of treatment is recurrent and very high. Importation and establishment of their specialist natural enemies might reduce their populations permanently to a lower level. Such inoculative (or classical) biological control was attempted in the 1920s in Hawaii against Gryllotalpa orientalis Burmeister, and in the 1930s in Puerto Rico against Scapteriscus didactylus (Latreille), but the level of success was not measured. Introductions of inoculative biocontrol agents into Florida in the 1980s against Scapteriscus vicinus Scudder, S. borellii Giglio-Tos, and S. abbreviatus Scudder, are now beginning to result in areawide reduction of populations of these pests. This should reduce the use of pesticides, and result in substantial economic savings. It should also reduce risk to the environment of contamination with chemicals. Three such biocontrol agents were released and established by personnel of the University of Florida’s Institute of Food and Agricultural Sciences (IFAS) research program. They are Larra bicolor Fabricius (a digger wasp), Steinernema scapterisci Nguyen and Smart (an entomopathogenic nematode), and Ormia depleta (Wiedemann) (a tachinid fly). There is evidence of reduced populations of S. vicinus and S. borellii in areas where the fly and the nematode are established.