Cucurbit downy mildew pathogen has two genetically distinct host-adapted clades

North Carolina State University plant pathologists determined that the causal pathogen, Pseudoperonospora cubensis, has two genetically distinct host-adapted clades and also found that wild cucurbits can serve as reservoirs for this pathogen. Clade 1 isolates more frequently infect squash, pumpkin, and watermelon while clade 2 impacted cucumber and cantaloupe. They also found that evidence of recombination in clade 1 isolates but not clade 2 isolates.