EPIDEMIOLOGY OF SPINACH DOWNY MILDEW PATHOGEN PERONOSPORA EFFUSA

The objectives of this project include 1) Develop a standardized test to quantify inoculum in soil in the form of sporangia, mycelium, and oospores; 2) Develop a more thorough understanding of the epidemiological gaps addressing the relative importance of mycelium, sporangia, and oospores as primary inoculum and in generating genotypic (DNA fingerprinting) and phenotypic (virulence) diversity; and 3) examination of commercial fields and research field plots for (a) downy mildew presence; (b) determine if naturally occurring oospores are present in leaves; (c) examine potential mating type in bioassay crosses; (d) and, through a third party, do anonymous ¿trace-back¿ studies to determine if the pathogen can/was detected on seed, in seed-production fields, and determine spinach cropping history of fields with outbreaks.