Efficacy ofExserohilum monocerasfor the control ofEchinochloaspecies in rice (Oryza sativa)

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 × 10 7 conidia m −2 killed all seedlings of both barnyardgrass and E. glabrescens , whereas an inoculum dose of 5.0 × 10 7 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.