Influence of annual and biennial prescribed burning during March on the abundance of Amblyomma americanum (Acari: Ixodidae) in central Georgia.

Abstract

A 5-yr study to evaluate the influence of annual and biennial prescribed burning in March on the abundance of Amblyomma americanum (L.) was conducted on Oconee Wildlife Management Area in the Piedmont physiographic region of Georgia. Tick abundance on plots embedded in larger burned and unburned areas were monitored with cloth drags and CO2-baited cloth panels monthly during March through September from 1987 through 1991. Annual and biennial prescribed burning from 1988 to 1991 significantly reduced the abundance of larvae, nymphs, and adults but did not alter their seasonal trends of abundance. Annual burning more consistently suppressed all life stages than biennial burning. The magnitude of tick suppression tended to increase with successive burns, especially with the annual burning regime. The order of vulnerability to direct incineration appeared to be overwintered larvae > adults > nymphs; however, only overwintered larvae were highly vulnerable. Consistent reductions in larvae during June-September following burning were associated with reduced litter depths and presumably lowered habitat suitability. During years of fire omission, the abundance of larvae on biennially burned plots increased to levels equal to or exceeding those on unburned plots. Based on cloth drag sampling, mean percentage control during 1988-1991 for larvae, nymphs, and adults, respectively, was 80, 75, and 70% on annually burned plots and 48, 73, and 65% on biennially burned plots. Frequent late-winter prescribed burning, which is commonly used to achieve wildlife habitat management objectives, could be an effective and economical component of an integrated A. americanum control program in habitats ecologically suited to regimes of frequent fire.