Enemies of the skin: Expert shares management guidelines on serious potato blemish diseases

Related imageSilver scurf and black dot are potato blemish diseases that are growing in prevalence and economic importance. These diseases are challenging to control and require an integrated effort to reduce their impact on potato production. So says Dr Amanda Gevens, Associate Professor & Extension Specialist in the Plant Pathology Department at the University of Wisconsin-Madison in the US. Earlier today, she addressed attendees at the 2018 International Crop Expo in Grand Forks, ND. “Silver scurf and black dot are both diseases which cause tuber discoloration that makes infected tubers unmarketable. Scurf and black dot are caused by separate fungal pathogens that have distinct life cycles, however. Management strategies mostly consist of cultural and chemical controls, and are hindered by the lack of commercially available resistant cultivars,” Gevens told the meeting. 

During her presentation, she offered information on symptom and disease detection and character, discerning features of silver scurf and black dot, and results of a multi-year field and storage trial conducted by her and her research team.

The trial evaluated roughly 25 field fungicide programs, including seed-treatments, in-furrow applications, and foliar treatments in 2015-2017 for emergence, yield, and silver scurf and black dot tuber incidence and severity.  Tubers from six treatments from each field trial, in each year, were taken into storage for further evaluation of post-harvest fungicides Phostrol and Stadium.

“In summary, the best and most consistent full season programs included one or more of the following inputs,” Gevens said. “Seed treatment with Maxim MZ, in-furrow treatment with Quadris or Elatus, post-harvest treatment with Stadium.”

Amanda Gevens can be reached at gevens@wisc.edu for further information.