VIEW ARTICLE

Biology and Control of Ergot on Male Sterile Wheat and Barley. S. B. Puranik, Ford Foundation Fellow, Department of Botany and Microbiology, Montana State University, Bozeman 59715; D. E. Mathre, Associate Professor, Department of Botany and Microbiology, Montana State University, Bozeman 59715. Phytopathology 61:1075-1080. Accepted for publication 5 April 1971. DOI: 10.1094/Phyto-61-1075.

A technique of inoculation of male sterile barley and wheat with Claviceps purpurea was developed, involving the removal of the upper 2-4 mm of the glumes prior to inoculation with a conidial suspension. Nearly 100% head and floret infection resulted. Maximum infection occurred with 10⁵ or more conidia/ml. Inoculation during and shortly after anthesis resulted in high levels of floret infection. With unfertilized florets, susceptibility declined at 10 days and was lost completely 15 days after the initiation of anthesis. Fertilized ovaries were susceptible right after fertilization. Four days after fertilization, susceptibility decreased until no infection occurred 9 days after fertilization. Under field conditions using male sterile barley, 2,400 µg/ml benomyl applied 3 times just prior to and during anthesis gave some control of ergot. Floret infection was reduced from 83 to 5% when 1,000 µg/ml benomyl was applied to florets with the upper portion of their glumes removed. This indicated that benomyl must reach the surface of the ovary at or before infection to be effective, as benomyl did not act as an eradicant against this pathogen. In male sterile wheat, Chris had some degree of resistance in comparison to other varieties tested.