Previous View
APSnet Home
Plant Disease Home



New Race of Plasmopara halstedii Virulent on Resistant Sunflowers in South Dakota. M. L. Carson, Assistant Professor, Plant Science Department, South Dakota State University, Brookings 57007. Plant Dis. 65:842-843. Accepted for publication 28 July 1981. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-842.

A new race of Plasmopara halstedii capable of overcoming the PI2 monogenic resistance in sunflower (Helianthus annuus) has been found in a hybrid demonstration plot near Brandt, SD. None of the known sunflower genes resistant to P. halstedii are effective against this race.

Keyword(s): downy mildew, pathogen variability.