STORECAST: Storage Potato Disease Risk Indexing
In the years 2008 through 2010 Pest Pros Inc. tested 108 commercial potato fields pre-harvest for storage disease risk using a system developed by Dr. Walt Stevenson and Dr. Zahi Atallhah, potato disease specialists at the UW-Madison, Department of Plant Pathology. Pest Pros and Dr. Stevenson's lab have collaborated since 2005 on the project to fast track the systems commercial application. The process is now trademarked under the new name STORECAST.
Tuber samples from each field were tested, using real-time PCR, for background loads of soft rot, pink rot, and pythium leak inoculum and a storage disease risk assessment made for each field. Fields were indexed from 1 - 5 (very low - high risk) for disease risk. The storage bins were monitored and rated from 1 - 5 (very low rot - high rot) for the development of storage rot. The varieties included Russet Burbank and chipping varieties for processing. Only non-symptomatic tubers were tested for disease potential.
A comparison of the "Storage Potato Disease Risk Index" (from PCR), to the storage rot outcome through April shows that 76% of the forecasted disease predictions were either in complete agreement or very close to the final disease outcome in storage. Only 2% of the indexes produced false negatives where the test predicted low disease risk with subsequent moderate to heavy rot in storage. False positives occured in 22% of the fields where less rot developed than was predicted. The ultimate goal is to provide a means for growers to segregate their "risky" potatoes from their "healthy" potatoes and manage the "healthy" potatoes for quality in long term storage. Refinements in the index will be made to include adjustments for variety, soil type, environment, and pathogen.
