Myrothecium leaf spot
Pathogen: Myrothecium roridum
Hosts: Lamium, Molucella, Rudbeckia, Salvia, New Guinea impatiens
Symptoms: This disease causes leaf spots, concentric rings may develop in the lesions. Raised black sporodochia develop on diseased tissue. In high humidity sporodochia are encircled by a tuft white growth.
Spread: Spores are splash dispersed by irrigation water and rainfall.
Management: Avoid injuries to plants, young or injured tissue is most susceptible. One common cause of wounding of perennials is packaging for shipping; disease readily develops following shipping. Avoid excessive fertilization, high fertilizer rates that favor lush foliage growth have also been associated with disease outbreaks. Minimize periods of leaf wetness through careful timing of irrigation. Fungicide applications may be needed to control severe disease problems.
![Myrothecium lesion on New Guinea impatiens leaf](/pestid/uploads/images/Myrothecium-lesion-on-New-Guinea-impatiens-leaf-204x300.jpg)
![Multiple sporodochia](/pestid/uploads/images/Multiple-sporodochia-300x225.jpg)
![Raised Myrothecium sporodochia on leaf surface](/pestid/uploads/images/Raised-Myrothecium-sporodochia-on-leaf-surface-300x225.jpg)
![Lesion on New Guinea impatiens leaf](/pestid/uploads/images/Lesion-on-New-Guinea-impatiens-leaf-202x300.jpg)
![Ring spot on New Guinea impatiens leaf](/pestid/uploads/images/Ring-spot-on-New-Guinea-impatiens-leaf-300x300.jpg)
![Myrothecium lesion with tuft of spores](/pestid/uploads/images/Myrothecium-lesion-with-tuft-of-spores-300x225.jpg)
Other Documents in this Series
You Might Also Be Interested In
-
Overview of the Michigan State University Landscape Architecture Program
Published on November 9, 2020
-
Overview of the Michigan State University Construction Management Program
Published on March 4, 2021
-
SPDC’s Landscape Architecture Program has officially launched a mentorship program for students
Published on December 4, 2018
-
Environmental design graduate student named 2019 CANR Outstanding Student Leader
Published on April 23, 2019
-
2019 Message from the Director: SPDC celebrates 15th anniversary
Published on December 13, 2019
-
Landscape architecture student combines science with design
Published on May 18, 2021
Accessibility Questions:
For questions about accessibility and/or if you need additional accommodations for a specific document, please send an email to ANR Communications & Marketing at anrcommunications@anr.msu.edu.