USING REMOTE-SENSING TO PREDICT OUTBREAKS OF ESTRUS-OVIS IN NAMIBIA

The Directorate of Veterinary Services of the Ministry of Agriculture, Water and Rural Development of Namibia issues warnings to farmers in the south of the country about the likelihood of infestation of small- stock by the nasal bot fly, Oestrus ovis. Farmers can then treat their stock at the most appropriate time. The O. ovis puparia develop at sh allow depths in the soil and the timing of emergence is directly depen dent on climatic conditions, specifically the number of degree-days ab ove a particular threshold soil temperature, Based on temperature meas urements from only a few stations scattered throughout the country, th e veterinary department warnings lack precision in space and time. Thi s paper presents an attempt to support the programme of warnings with accumulated temperature information from Meteosat satellite images, in order to strengthen predictions of the time of emergence in specific places, and to improve the precision and reliability of warnings given to farmers. (C) 1998 Elsevier Science B.V.