Fig. 2. Distribution of generalist and specialist S. hermonthica in published studies. Relative emergence was calculated as the mean number of parasites emerged on a particular host species, relative to the highest emergence observed for any tested host genotype. A) Dendrogram obtained from hierarchical clustering of mean relative emergence values for three hosts. B) Relative emergence on maize, sorghum, and pearl millet for S. hermonthica from 27 localities. Boxplots represent the distribution of relative emergence values across all tested genotypes of a host species. Whiskers extend to the minimum and maximum values and boxes indicate the first and third quartiles. The black ‘x’ shows the value of the Paired Difference Index (PDI) calculated for each population, where values closer to 1 indicate more specialized populations. Vertical dashed lines demarcate S. hermonthica clusters determined in A. Parasites were classified in the following groups: 1) millet specialists, 2) millet/sorghum generalists, 3) sorghum specialists, 4) virulent generalists (where high emergence is observed across multiple host species), 5) maize/sorghum generalists, and 6) two populations that were excluded from the clustering analysis because emergence on maize was not tested. C) Host crop production in S. hermonthica-prone regions. Colored regions indicate the most abundant host crop based on estimated area harvested in 2000. Note pearl millet is not distinguished from other millets in harvest area data. D) Inset map. Black symbols (n=27) indicate group assignments from (A) and the location of origin of S. hermonthica populations tested for emergence in empirical studies.