Issue 2, May 5, 2021

Mayapple Rust

You probably won't find mayapple (Podophyllum peltatum) in a typical landscape. However, this herbaceous perennial is common in many woodland areas. The plant emerges in early spring to capture sunlight before trees canopies above produce leaves and shade.  Mayapple then senesces and goes dormant by mid-summer. I recently encountered numerous mayapple colonies, with their unmistakable umbrella-like leaves, while walking through my neighbor's wooded lot.   

Mayapple infected with rust

Several of the plants had symptoms of mayapple rust. The upper surface of the affected leaves displayed yellow or light green spots, while the lower leaf surfaces displayed striking, bright orange spores and pustules.  Some leaves puckered where the lesions occurred. Despite the appearance and some leaf drop, mayapples seem to tolerate the disease without permanent injury. Mayapple rust is not considered a significant problem and does not require treatment.

Mayapple infected with rust

Interestingly, mayapple rust is autoecious and does not require an alternate host. This contrasts with the heteroecious rust diseases that infect many landscape plant species. Herteroecious rust diseases,  such as cedar-apple rust, need two host plant species to complete their life cycle.

The mayapple rust pathogen was previously named Puccinia podophylli. In 2012, Minnis et al. resurrected Allodus podophyllias as the accepted name for this species based on DNA sequence analysis of this and other rust species. For information on the name change view: Mayapple Rust Ressurection https://driftlessprairies.org/wp-content/uploads/2015/02/Mayapple-Rust.pdf

Author:
Travis Cleveland

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