Assessment of Management Practices at Vine Kill on Silver Scurf and Black Dot of Potato in Washington, 2023

Silver scurf and black dot, caused by the fungal pathogens Helminthosporium solani and Colletotrichum coccodes, respectively, are the most common surface blemish diseases observed on potato ( Solanum tuberosum L.) tubers across the United States. This report evaluates the effect of vine kill procedures (the dessicant used and the application timing relative to mowing) and the timing for termination of irrigation on silver scurf and black dot. Results from two field trials conducted in 2023 at the Washington State University (WSU) Othello Research Farm and the WSU Mount Vernon Northwestern Washington Research and Extension Center (NWREC) reemphasize that extending the interval between vine kill and harvest will increase risk of silver scurf and black dot.