Abstracts of the ASHS Southern Region 65th Annual Meeting

National Sweetpotato Collaborators Group AN IN-DEPTH SURVEY OF SWEETPOTATO PACKING AND HANDLING PROCEDURES IN NORTH CAROLINA B.A. Edmunds and G.J. Holmes; Dept. of Plant Pathology, North Carolina State University, Raleigh NC 27695 Methods of packing and handling sweetpotatoes are important for miti gating postharvest losses due to decay. The goal of this work is to take a critical look at the packing and handling processes in North Carolina (NC) sweetpotato packinghouses. Similar surveys are being conducted in Louisiana and Mississippi as part of a multi-state project. The survey is inclusive of all packingline operations including sequence of machinery components, length and speed of the packingline, decay control products/strategies used, and impact (bruising) measurements. Packingline impacts are quantified and characterized using a SmartSpud. This instrumented device is placed on the packingline where it is conveyed alongside sweetpotatoes, measur ing the impact forces exerted and sending the data via a radio signal to a handheld personal digital assistant (PDA). The information on the PDA is downloaded onto a computer where the results can be displayed in more detail and analyzed. Packinghouse personnel respond well to this visual display and willingly spend one hour being interviewed, discussing the results of the survey, learning about the trouble spots on their lines, and getting advice on how to reduce potential injuries. About 15 out of 30 NC packinghouses have been surveyed (this includes all of the high-volume packinghouses). We typically found the largest impacts (30–70 G) occurring during dumping and at unprotected conveyor changes. Packinglines vary in length from 88 ft to 277 ft with run time varying from 3.5 min to 10 min. Lines all share the same basic components (dump, eliminator, brushbeds, sizer, etc.) with layout and design modified to suit individual needs and space requirements. A variety of decay control methods are in use with about one half of packers surveyed routinely applying the fungicide Botran. EFFECT OF ALTERNATIVE POSTHARVEST DIP TREATMENTS ON RHIZOPUS SOFT ROT OF SWEETPOTATO B.A. Edmunds* and G.J. Holmes; Dept. of Plant Pathology, North Carolina State University, Raleigh NC 27695 Most sweetpotato packers use the fungicide Botran (dicloran) to reduce losses caused by Rhizopus soft rot. However, certain markets are no longer accepting Botran-treated sweetpotatoes and packers are searching for suit able alternatives. We evaluated 12 products applied as dip treatments for their ability to control Rhizopus soft rot. Sweetpotato roots (‘Hernandez’) were wounded and artificially inoculated with a Rhizopus spore suspension (106 spores/mL). Roots were dipped for 30 sec. in treatment solutions and stored at about 65 °F. After 10 days, roots were evaluated for incidence of decay. The inoculation method produced 100% decay in nontreated roots. Bio-Save 11LP and Pristine, a biopesticide (strain of Pseudomonas syringae) and reduced-risk chemistry respectively, both provided very high levels of decay control. Other products such as Biosave 10LP (a different strain of P. syringae), Scholar and Freshgard 25 were marginally effective, while copper ionization, bleach, and Storox were ineffective against Rhizopus soft rot. USING GIS TO ANALYZE SWEET POTATO WEEVIL TRAP DATA IN LOUISIANA Arthur Villordon*1, Craig Roussel2, and Tad Hardy2; 1LSU AgCenter Sweet Potato Research Station, Chase, LA 71324; 2Louisiana Depart ment of Agriculture and Forestry Agriculture, P.O. Box 3596, Baton Rouge, LA 70821 The Louisiana Department of Agriculture and Forestry (LDAF) conducts sweetpotato weevil (SPW) (Cylas formicarius Fabricius) monitoring as part of the statewide SPW quarantine program. This activity involves a statewide pheromone-based trapping program that monitors sweetpotato beds and production fields. We conducted GIS analysis of SPW trap data, collected over three years, to assess the potential use of publicly available GIS tools in managing and interpreting the data. Trap data was mapped to specific beds and f ields in each of three years, generating layers that clearly showed fields and parishes that reported high trap counts. GIS analysis showed potential SPW hotspots in each year, indicating that certain beds or fields are predisposed to SPW infestation than others. This information can be useful in planning SPW management strategies by growers and other stakeholders. The GIS database also provides the foundation for the development of descriptive and predictive models of SPW occurence not only in Louisiana, but in other states where SPW is a potential pest. For example, using presence data for Louisiana and Genetic Algorithm for Rule Set Prediction (GARP), a GIS-based ecological niche modelling tool, we were able to generate predicted distribution using mean minimum temperature for January as the predictor variable. Although additional work is needed to identify other predictor variables and verify the models, the results demonstrate the potential use of GIS-based tools for generating warnings or advisories related to SPW. A WEB-ACCESSIBLE GEO-REFERENCED DATABASE OF SWEETPOTATO ACCESSIONS FOR TANZANIA AND KE NYA A. Villordon*1, S. Gichuki2, H. Kulembeka3, S.C. Jeremiah4, and D. Labonte5; 1LSU AgCenter, Sweet Potato Research Station, 130 Sweet Potato Road, Chase La 71324;2Kenya Agricultural Research Institute, Biotechnology Centre, P.O. Box 57811, Nairobi; 3MAF Department of Research and Development, ARI-Ukiriguru, P.O. Box 1433, Mwanza; 4MAF Department of Research and Development, ARI-Ukiriguru, P.O. Box 1433, Mwanza; 5Louisiana State University, Department of Horticulture, 137 JC Miller Hall, Baton Rouge, La 70803 One of the secondary centers of genetic diversity for the sweetpotato [Ipomoea batatas (L.) Lam.] is located in Africa. We have developed a geo referenced database of sweetpotato accessions for Tanzania and Kenya that is accessible by stakeholders and other users. Public domain base maps and other files were used to generate the underlying GIS components. DIVA-GIS was used to convert existing spreadsheet-based accession and passport data into GIS-compliant files. ALOV Map, a public domain Java application for publishing vector and raster maps, was used to provide the framework for a web-accessible GIS database. This demonstrates that the availability of pub licly available software requiring minimal or flexible licensing costs provide a cost-effective alternative to institutions that are considering developing GIS databases as well as enabling web accessibility to such resources. DIVA-GIS was also used to predict potential distribution of sweetpotato germplasm in Sub-Saharan Africa using the built-in ecological niche modelling tool. We describe procedures, software, and other applications that we used to develop a publicly accessible web interface to a GIS database of sweetpotato germplasm collections in Kenya and Tanzania. CHARACTERIZATION OF RESISTANCE TO ROOT-KNOT NEMATODES IN SWEETPOTATO J.A. Thies;* U.S. Vegetable Laboratory, USDA, ARS, Charleston, S.C. Thirteen sweetpotato (Ipomoea batatas) genotypes were characterized for resistance to Meloidogyne incognita, M. javanica, M. hapla, and M. arenaria races 1 and 2 in greenhouse tests. The following sweetpotato genotypes representing a range of reactions to M. incognita were evaluated: U.S.