SEASONAL AND ANNUAL ABUNDANCE OF AMBLYOMMA-AMERICANUM (ACARI, IXODIDAE) IN CENTRAL GEORGIA

Seasonal and annual changes in the abundance of Amblyomma americanum ( L.) larvae, nympbs, and adults were monitored over a 5-yr period in th e Piedmont physiographic region of Georgia. Tick abundance was monitor ed with cloth drags (all life stages) and CO2-baited cloth panels (nym phs and adults) monthly during March through September from 1987 throu gh 1991. Larvae appeared in substantial numbers in July and were most numerous in August and September. Small numbers of unfed larvae appare ntly overwintered each year based on their presence during March, Apri l, or May. Nymphs were most numerous from April through June and decli ned to much lower numbers by August and September. Adults were most nu merous from March through May and virtually disappeared by August. The se seasonal patterns were similar to those reported for A. americanum at other southeastern locations. Each life stage exhibited similar tre nds of annual abundance with an increase in 1988 followed by a relativ ely steady decline to levels equivalent to or below initial 1987 value s by 1991. Major environmental variables that potentially could have i nfluenced annual abundance were identified from Haile & Mount's (1987) computerized model of A. americanum population dynamics. Habitat type , host density, and day length were constants and rationally could be excluded as causes of annual variations in abundance; weather and host -finding rate were presumed to have been primarily responsible for the se annual differences.