Phytophthora Prediction

Phytophthora Prediction

The University of Massachusetts at Amherst’s Stockbridge School of Agriculture is currently undertaking research into a system which would aid in predicting and managing Phytophthora outbreaks using real-time PCR (Polymerase Chain Reaction-a biochemical technology in molecular biology used to amplify a single or a few copies of a piece of DNA across several orders of magnitude, based on the ability of DNA polymerase to synthesize a new complementary strand of DNA when offered a template) and risk mapping. Their goal in developing this new system is that it generates the ability to rapidly respond when incidences are reported.

Two species of exotic Phytophthora fungus; P. infestans and P. capsici, are deemed the most devastating diseases to New England farms. Crops generally grown in this region including, cucumbers, tomatoes, peppers, eggplants and potatoes are very susceptible, the potential detriment from Phytophthora is near catastrophic; over 8,000 acres of susceptible vegetables were harvested in 2007. Losses from these diseases have totaled several hundreds of thousands of dollars in the northeast and Canada; a 2009 outbreak, caused by a 2 unique genotypes of P. infestans devastated the region’s tomato and potato crop. Many farms in southern New England have firmly established populations of P. capsici, research indicates that the spores of this fungus are able to overwinter frozen and remain viable. Phytophthora species are able to propagate very quickly when conditions are right; when soil moisture is excessive and soil temperatures are between 59 and 86 degrees Fahrenheit, making it optimal to control outbreaks during early stages.

These incidences catalyzed efforts to monitor for outbreaks on Massachusetts farms and develop this rapid response system which would identify new outbreaks, determine clonal lineages, help predict which areas may be most susceptible which will aid in options for control methodologies. Unfortunately some techniques for managing this disease in the past are now resisted by the virulent species and genotypes. Forecasting models in current use were developed for use over large areas and do not account for site or case history or site level monitoring. They are still very useful but does not have the accuracy needed for farm-scale monitoring as is necessary in Massachusetts, and beyond. Accurate data are intrinsic to effectively mapping risks, but can be very difficult to obtain however without this fundamental data risks cannot be accurately assessed or predicted and management plans may not achieve efficacy necessary to contain and eradicate this threat. Researchers at the Stockbridge School aim to obtain necessary data to be able to successfully implement an effective rapid response network.