Cucurbit downy mildew is caused by the fungus-like oomycete pathogen Pseudoperonospora cubensis (P. cubensis). There are two types of P. cubensis isolates that can infect cucurbit crops and weeds referred to as clade 1 or clade 2 isolates. Isolates belonging to clade 1 tend to more frequently infect watermelon, pumpkin, and squash while isolates belonging to clade 2 more frequently infect cucumber and cantaloupe. Isolates belonging to clade 2 can quickly become resistant to fungicides, thus, fewer effective fungicides ara available for downy mildew control in cucumber and cantaloupe.
Source: Cucurbit Downy Mildew | NC State University
Cucurbit downy mildew is caused by the fungus-like oomycete pathogen Pseudoperonospora cubensis (P. cubensis).
