Penetration of the eastern subterranean termite into soil treated at various thicknesses and concentrations of Dursban TC and Premise 75.

The ability of eastern subterranean termites, Reticulitermes flavipes (Kollar), to penetrate various concentrations and treatment thicknesses ranging from 1.0 to 50.0 mm of Dursban TC and Premise 75 was evaluated in a laboratory bioassay. Termites penetrated only a few millimeters into 500 ppm Dursban TC-treated soil at all thicknesses. As concentration decreased, termite penetration into Dursban TC-treated soil increased with termites generally penetrating completely through 5.0- and 0.5-ppm treatments. Termites penetrated at least 30% into 10-, 25-, and 50-mm thicknesses of 100 ppm Premise 75. Termites generally completely penetrated all concentrations < or = 100 ppm and thicknesses < or = 5 mm. At 7 d, termite mortality was 100% at all treatment thicknesses of Dursban TC at 500 and 50 ppm. At 5.0 and 0.5 ppm Dursban TC, termite mortality ranged from approximately 45 to 98% across all treatment thicknesses. At 100- and 10-ppm concentrations of Premise 75-treated soil, termites suffered > or = 75% mortality. Premise 75 at 1.0 and 0.1 ppm generally killed < or = 50% of the assayed termites at all treatment thicknesses.