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Disease Note. First Report of Mycosphaerella rabiei on Chickpeas in the Western Hemisphere. W. J. Kaiser, Regional Plant Introduction Station, Washington State University, Pullman 99164. R. M. Hannan, Regional Plant Introduction Station, Washington State University, Pullman 99164. Plant Dis. 71:192. Accepted for publication 1 December 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0192E. Mycosphaerella rabiei Kovachevski is the teleomorph (perfect state) of Ascochyta rabiei (Pass.) Labrousse, the causal organism of Ascochyta blight of chickpea (Cicer arietinum L.). The teleomorph was first described by Kovachevski (1) on overwintered chickpea refuse in Bulgaria in 1936 and has subsequently been reported from the USSR (1958) and Greece (1963). In March 1986, M. rabiei was isolated from chickpea stems and pods that had overwintered in a field near Genesee, Idaho. The field had been seeded to chickpea cultivar UC-5 in April 1985, and the planting was severely damaged by Ascochyta blight in June 1985. In September 1985, the field was disked and seeded to winter barley. In March 1986, after a winter of heavy snowfall and extended periods of freezing temperatures, abundant pseudothecia containing asci and ascospores of M. rabiei were found imbedded in chickpea debris on the soil surface. The cylindrical-clavate asci contained eight bicellular ascospores, which were pathogenic to several chickpea accessions in controlled inoculation tests in the greenhouse. The teleomorph appears to play an important role in the epidemiology of the disease in northern Idaho, owing to potential long-distance dissemination of airborne ascospores. Discovery of the teleomorph helps to explain how the pathogen is spreading to fields in the Genesee area, where chickpeas have never been grown before and where apparently clean seed had been planted. |