Location: Subtropical Plant Pathology Research
2013 Annual Report
During the initial phase of the project we organized a 3-day meeting of the collaborators. We designed a framework for the model based on multiple parameters broken into discrete phases of the distribution pathway, i.e., disease/infection, packinghouse/transport, and distribution/marketing. Each phase was them populated with data extracted from the existing literature on black spot. The data was organized and fitted to likelihood distributions. Each distribution was linked to the next distribution or step in the pathway in series. The result was a simplified, functional model for the entire pathway. Additional steps, i.e., data distributions, can then be added as more data are gleaned from literature and/or via gap-filling research. Where data was missing, we estimated distribution functions. We then ran the initial model to identify any programming issues and found none.
We charged individual collaborators with collecting data we will put it into the model. We came to consensus on estimates of missing distribution functions. We identified data gaps and assigned individual collaborators to commence the research to fill them. Post conference, we began to modify the model to include additional pathway components identified and data provided by the international research team. No changes to the approach were needed at this time.
During the second phase, the model continued to be refined by identifying and adding data for individual steps in the marketing and distribution pathway. We identified, clarified and initiated gap filling research on:.
During the third phase, data was gleaned from literature on black spot now has been incorporated into the model and the model continues to be refined. This data was incorporated by defining new mathematical distributions relative to each data parameter and incorporating these distributions into the various steps of the model pathway. We determined/modified locations as points of origin and end points of fruit distribution and obtained, and these have now been incorporated into the model framework.
During the third phase of the grant, we had our 2nd meeting and spent three days going through all steps of the model verifying each step in the pathway and discussing it in detail. We identified additional gap filling research that was needed to either complete the model or strengthen the model at various points in the pathway. Assignments of gap filling research were accepted by Brazilian, South Africa, and U.S. members of the team. The Brazilian team members conducted gap-filling research on port of entry rejection and the number of fruit disposed of and/or diverted at that point in pathway; and examined the incidence of disease fruit pre-and post-packinghouse to determine the culling rate for CBS for that step pathway. They also explored harvesting of entire trees and the number of infected fruit that occur at the center of the tree versus at the periphery and the whole tree.
The South African team conducted a series of experiments to determine the percentage of culls due to CBS postharvest, number of CBS symptomatic fruit that are packed, i.e. lesion fruit that are missed during packinghouse, lesion development during cold storage and shelf life, and picnidiospore production and viability in packinghouse treated versus nontreated fruit. South Africans also explored estimates of the incidence increase due to latent infections.
Members of the U.S. team examined fruit disposal from prior studies conducted by USDA APHIS to determine how and at what proportion consumers discard fruit and explored the susceptibility of infection of various endpoints of pathways, i.e. regions within various countries, from the CBS data from NAPFAST.
The group talked with a local fruit packer to understand not only the packinghouse but various steps within the pathway including shipment from the field to the packinghouse, storage into greening rooms, shipping to international ports, redistribution and transshipment to end points, distribution to endpoint losses, market losses, consumer losses, and consumer discard of declining fruit as well as peels from consumed fruit. We also discussed how to obtain better data for post-packinghouse distribution, shipment and transshipment, marketplace and consumer losses.
During the fourth phase of the project, we had our 4th meeting. Once again we went through all steps of the model verifying each step in the pathway and discussing it in detail and identified additional gap filling research that was needed to either complete the model or strengthen the model at various points in the pathway.
Data were provided by Brazil to uncover a distribution where a probability is assigned to x number of days with “suitable” conditions for infection. Brazilian members ask Spanish colleague for more quantification associated with the how much cull from packinghouses in Spain go to juice, feed animals, or just sit in the grove. Brazilians shared studies:.
The major results of a South African studies were provided. Percent of lesions was evaluated before fruit went to the packhouse, fruit that was culled from the packhouse, and fruit that was determined to be “export quality”. This data was use for the efficiency of the packinghouse process to reduce the numbers of fruit with CBS lesions that continue through the model chain. We discussed is a study could be done to better quantify the accuracy of visual inspection of fruit for lesions versus testing via PCR. South Africa discussed:.
Contemplated 10 pathways that should be highlighted in the manuscript. For each we need:.