Field surveys of pearl millet downy mildew - effects of hybrids, fungicides and cropping sequence uri icon

abstract

  • Pathogenic and genetic diversity in Sclerospora graminicola, the pearl millet downy mildew pathogen, is a major cause of a reduced effective life of commercial FJ hybrid cultivars in India. We conducted surveys during 1994-2000 of pearl millet crops in farmers' fields in Maharashtra, the state that has the largest area (ca. I million ha) under hybrids, to assess the incidence of downy mildew in hybrids. Results indicated: i) a rapid increase in the number of hybrids grown in the region, from 3.in 1994 to 26 in 2000, with the majority of seeds produced arid marketed by commercial seed companies; ii) a new resistant hybrid when grown consecutively in the same field for more than three crop seasons often became susceptible to, downy mildew (with up to 100% incidence) indicating the emergence/selection of new virulence; Hi) seed treatment with the systemic fungicide- metalaxyl was not always effective in significant reduction of liowny mildew incidence and of oospore production in some hybrids~ and iv) cropping sequences, where previous crops were cotton, coriander and onion, had significantly lower downy mildew incidence compared with other crops

publication date

  • 2003