The seasonal abundance of adult ixodid ticks on Merino sheep in the south-western Orange Free State.

With the exception of October, when no collections were made, adult ticks were collected at weekly intervals from February 1986 to January 1987 from 20 randomly selected sheep out of a flock of 60. Ixodes rubicundus was the most abundant tick and was present from April to September with a peak during May. Hyalomma marginatum rufipes was the next most numerous tick. It was recovered throughout the year with peak burdens being recorded from November to April. Small numbers of a Rhipicephalus sp. (near R. pravus) were also collected. These exhibited a major peak during February and a minor peak during August. A dipping programme to prevent the paralysis caused by I. rubicundus and the Rhipicephalus sp. (near R. pravus) is suggested.