Issue link: http://read.uberflip.com/i/815832
WWW.POTATOGROWER.COM 21 S upplying disease-free seed for the potato industry has always been a challenge, but new hurdles have been placed in front of us with the emergence and spread of three viruses that cause necrosis in tubers: the necrotic strains of potato virus Y (PVY), potato mop- top virus and tobacco rattle virus. A multidisciplinary team of 31 researchers from nine universities and the USDA Agricultural Research Service with expertise in potato breeding, entomology, plant pathology, agronomy and economics are working together with seed certification programs and the potato industry to understand the biology of these viruses and provide practical management options. One objective of the program is to develop and distribute accurate and reliable sampling and testing procedures that will allow seed certification and other testing labs to determine virus incidence in dormant tuber samples. This could provide an alternative to the post-harvest winter grow-outs currently done in Hawaii, Florida or greenhouses. Other diagnostic tests are being developed to quantify from soil the stubby root nematode vector of tobacco rattle, and the causal agent of powdery scab, Spongospora, which is also the vector of mop-top. This would allow growers to determine whether the tobacco rattle and mop-top vectors (and ultimately the viruses) are present in their fields and pose a threat prior to planting the crop. Other research under this objective includes the development of remote sensing diagnostics that use changes in the light reflectance properties of virus-infected potato plants to distinguish among healthy and diseased plants. WWW.POTATOGROWER.COM 21 Internal symptoms of potato mop-top virus are clearly visible in these cross-sections.