Residual Effectiveness of Chlorinated Hydrocarbons for Control of the Imported Fire Ant1

Abstract

Experiments were conducted in Alabama from 1953 to 1958 on control of the imported fire ant, Solenopsis saevissima v. richteri Forel. Chlordane as a dust and in granular formulation, aldrin in emulsion spray and granular formulation, dieldrin in emulsion spray and granular formulation and in fertilizer mixture, and heptachlor in granular formulation and fertilizer mixture were applied in late winter or early spring in a series of experiments to permanent sod lands. Two pounds of heptachlor or dieldrin, or 4 pounds of chlordane per acre, when broadcast as granules, were highly effective for control of the ant and afforded good control for a period of 3 to 5 years. In one experiment, granulated dieldrin was effective for a longer period than a dieldrin emulsion spray. Lower dosages of the insecticides gave good control for 1 year after treatment, but they were ineffective thereafter. When the insecticides were mixed with fertilizer, approximately the same degree of fire ant control was obtained as when the insecticides were used alone. Chlordane mound treatment killed the ants in the treated mounds but did not prevent reinfestation. When broadcast treatments lost their effectiveness, the number of mounds per acre was greater than on the non-treated areas, but the new mounds were smaller in size. Based on 1-year results, airplane application of 5% or 10% heptachlor at a rate of 2 pounds of technical material per acre were equally effective for control of the imported fire ant. Soil type appeared to have no effect on fire ant control.