Screening of Fungi and Bacteria For Control of The Forest Tent Caterpillar 1970-1973

The original objective of the study was to screen various fungi imperfect! for eventual use in control of the forest tent caterpillar In southern river bottom hardwoods. Initially, only Beauveria bassiana, Spicaria sp. and Metarrhizium sp. were screened; however, commercial preparations of Bacillus thuringiensis (Thuricide 90 ts, Thuricide HPC, Biotrol A-12, Biotrol W-25, and combinations of these) were later screened. Combinations of B. bassiana and the B. thuringiensis preparations also were tested. Tent caterpillars were sprayed with the various preparations and maintained in a chamber at 21°C. Thuricide concentrations ranged from 416 to 8,333 ppm. Biotrol and B. bassiana preparations ranged from 0.25 to 10 mgs. per petri dish. Each dish contained 10-50 2nd, or 3rd instar larvae. Since Spicaria sp. and Metarrhizium sp. showed low virulence, they were eliminated from the study after the initial tests. The effectiveness of the various preparations is summarized in the table.