Location: Emerging Pests and Pathogens Research
Project Number: 8062-22000-022-014-I
Project Type: Interagency Reimbursable Agreement
Start Date: Mar 1, 2017
End Date: Dec 30, 2020
Objective:
The primary purpose of this agreement is to support investigations of two soil-borne viruses and a soft rot bacterium that have recently emerged as major concerns in US seed potato production and are becoming more widespread in commercial potato plantings. Potato mop top virus (PMlV) and Tobacco rattle virus (TRV), transmitted by soil dwelling protists and nematodes,respectively, induce no foliar symptoms on most potato cultivars, but cause
internal tuber necrosis that render tubers unmarketable. The presence of either virus can restrict domestic and international trade of seed and ware potatoes. A new and aggressive Dickeya soft rot bacterium, D. dianthicola, causes blackleg and tuber soft rot. Planting Dickeya-infected seed potatoes results in very poor stands or plants that wilt and die after emergence, generally when temperatures reach 25-3oec. Cool growing conditions in many seed production areas can suppress symptoms and detection by normal seed certification practices. The rapid penetration of these pathogensinto the US potato industry, and particularly the seed industry, combined with a lack of detection methods
and management methods has created a critical and urgent need for research and engagement with affected producers, the allied inustry, and the regulatory agencies.
Approach:
Our plan is to better understand the scope and distribution of the pathogen problems in the seed potato crop,improve on existing technologies for detection of all pathogen strains or species that are emerging,transfer the technologies and help build an infrastructure to improve the capabilities and response of seed certification programs, and to provide growers and regulators with timely information on best management practices. The specific aims of this three year proposal are:
1. To develop improved detection methods for use with dormant tubers,soil and water for PMTV, TRV and D. dianthicola.
2. To develop improved management methods for tuber necrosis caused by PMTV and TRV, and for blackleg and tuber soft rot caused by D. dianthicola.
3. To provide extension information and economic analysis about PMTV, TRV and D. dianthicolato seed potato farmers, commercial potato farmers,and to seed potato certification agencies.
Initial efforts will work with seed certification programs and use existing diagnostics to monitor the seed crop for incidence and distribution of these pathogens across the US. Concurrently, diagnostic assays will be optimized to detect the pathogens in dormant tubers so that the harvested seed crop can be tested prior to being distributed to the commercial potato industry. Minimizing the dispersal of the pathogens in infected seed is a critical management strategy to prevent the infestation of other production fields. Additionally,the diagnostic assays will be optimized for detecting the pathogens and associated vectors in soil so that growers and regulatory agencies can test fields prior to planting to minimize risk of harvesting an infected crop and perpetuating the disease in infested fields. Outreach activities will focus on educating growers and first detectors about the etiology and epidemiology of the diseases so the problems can be recognized early on and so they can implement measure to minimize the risk of introduction to or spread around farms. These activities will emphasize the economic consequences of allowing the disease to establish and spread and the economic benefits of early detection and testing to minimize risk. A three year timeline is needed to complete all of the proposed work, but since funding is allocated on yearly cycles, this work plan and milestones are developed for year one, FY2017.
