Foliar diseases of potatoes are often managed by growers using a calendar-based schedule with no knowledge of the local optimum conditions for disease development or if spores of the pathogens are present in the area at the required threshold for disease development.
During the summer of 2018, the University of Idaho and industry partners rolled out a spore trap network that uses recent developments in spore sampling technology and molecular diagnostics to detect airborne spores of potato pathogens.
These traps detect spores of pathogens that cause late blight, early blight, white mold, brown spot and grey mold. The network is comprised of 14 Burkard multi-vial cyclone spore samplers, which operate continuously for 7 days, automatically changing the sampling vial daily.
The network detected all five potato pathogens that were targeted, and results were disseminated weekly, initially within 48 hours of receiving the spore sample vials. Initial results suggest the brown spot and grey mold pathogens are widespread, although levels of these pathogens have appeared to decrease as conditions became drier and warmer.
The white mold pathogen was first detected at one site on June 11th with sporadic occurrences since then. The early blight pathogen was detected at four sites the week of 17th of June. The late blight pathogen was also detected that week at three sites, but no late blight symptoms on potato have been reported, and symptoms were not observed when nearby fields were scouted.
The researchers envision that the information obtained from the spore samplers, coupled with disease-weather models, can provide a powerful tool to warn potato growers of disease risk. Such information may lead a grower to apply early treatments or conversely alleviate the need for unnecessary treatments in the absence of disease pressure.
Further work is required to determine the optimum number and locations of spore sampling stations for confidence in the network as an early disease warning system.
Further information: Prof Kasia M. Duellman, Extension Seed Potato Specialist, University of Idaho – firstname.lastname@example.org
Source: Global Potato News