Squash Downy Mildew Found in North Carolina

Pseudoperonospora cubensis, the causal agent of cucurbit downy mildew (CDM), was confirmed on butternut squash in Lenoir on July 26 of 2021. The sample was part of a sentinel plot maintained by the NC State Vegetable Pathology Lab. The plot showed 10% disease incidence and leaves showed 2% disease severity.

disease symptoms on leaf

Figure 1: Circular, yellow lesions on topside of the leaves that are bound by leaf veins (Mariana Prieto, NC State Vegetable Pathology Lab).

view of spores through microscope

Figure 2: Pseudoperonospora cubensis clade 1 sporangia under a dissecting microscope (Dr. Savithri Purayannur, NC State Vegetable Pathology Lab)

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