Efficacy of an indigenous fungus, Exserohilum monoceras, for the control of 3 Echinochloa species was evaluated and compared under both regulated greenhouse and screenhouse (field plots netted with 2 layers of metal mesh screening to exclude vertebrate pests) conditions. Under greenhouse conditions, an inoculum dose of 2.5 × 107 conidia m−2 killed all seedlings of both barnyardgrass and E. glabrescens, whereas an inoculum dose of 5.0 × 107 conidia m−2 was required to obtain 100% mortality of junglerice seedlings. The 1.5-leaf stage of all 3 Echinochloa species was the most susceptible. Increasing inoculum density increased weed control efficacy on younger or older Echinochloa seedlings. The highest level of control was observed for E. glabrescens, less for barnyardgrass, and least for junglerice. Under screenhouse conditions, Exserohilum monoceras caused more than 90% mortality of Echinochloa species when the inoculum was formulated as an oil emulsion or when applied as a dry powder.
