Published online by Cambridge University Press: 10 July 2009
In this ecological survey conducted mainly in western Tanzania between 1962 and 1969, six species of Earias were found, including two undescribed species and E. cupreoviridis (Wlk.), which is restricted to Sida spp.; E. biplaga (Wlk.) and E. insulana (Boisd.) were the only species found on cotton and were virtually restricted to Malvales. Differences in the incidence of Malvales and the Earias larvae feeding on them were noted on a research farm and on surrounding local farms as being due to different farming practices and soil types. E. biplaga was the dominant species on cotton for most of each year and its major alternative host was Waltheria indica; E. insulana was relatively more common on cotton in the dry season and was particularly common on Abutilon spp. Populations of E. biplaga increased on W. indica early in the rainy season, then dispersed onto cotton; populations on cotton could be predicted from the size of earlier populations on W. indica and subsequent rainfall.