Claviceps sorghi (sorghum ergot).
Abstract C. sorghi is a pathogen of Sorghum bicolor found only in India and Southeast Asia. The more widespread Claviceps africana is predominant even in India; C. sorghi appears to be marginalized in its restricted range. A significant difference in invasiveness is the relative production of inoculum that spreads plant-to-plant. C. sorghi produces few to no secondary conidia from macroconidia on infected florets, whereas C. africana produces large numbers of these airborne propagules. The macroconidia of C. sorghi may themselves be transported in honeydew by wind, rain-splash, insects or direct contact between plants, but these are more limited means. Fungal sclerotia and/or the sphacelia state may be carried among harvested seed, but the seed lots can be cleaned or treated with fungicides (Bandyopadhyay et al., 1996). Alternative hosts are pearl millet (Pennisetum glaucum), wild and weedy relatives of S. bicolor, and wild grasses.