Inoculated host range and effect of host on morphology and size of macroconidia produced by Claviceps africana and Claviceps sorghi

Twenty graminaceous plant species were evaluated for their susceptibility to the two sorghum ergot pathogens Claviceps sorghi and Claviceps africana. Five species viz., Sorghum arundinaceum, Sorghum halepense, Sorghum versicolor, Sorghum virgatum and Pennisetum glaucum were found to become infected by both pathogens via inoculation with 106 conidia/ml. Species which did not become infected under these conditions included Pennisetum pedicellatum, Zea mays, and species of Panicum, Brachiaria, Cenchrus, Andropogon, Dichanthium, Chrysopogon, Iseilema, Bothriochloa and Chloris. Honeydew secretions were observed from infected flowers of susceptible plant species. There was marked variation in size of macroconidia of both C. sorghi and C. africana on different hosts on which the pathogens were able to establish symptoms. Dimorphism was observed for macroconidia produced on P. glaucum, as elliptical and spindle shaped macroconidia were observed. Based on inoculation under greenhouse conditions, we conclude that C. sorghi and C. africana may have similar host ranges.