2011 APS-IPPC Joint Meeting Abstracts of Presentations Abstracts submitted for presentation at the APS-IPPC 2011 Joint Meeting in Honolulu, Hawaii, August 6–10, 2011 (including abstracts submitted for presentation at the 2011 APS Pacific Division Meeting). The abstracts are arranged alphabetically by the first author’s name. Prioritizing cover crops for improving root health and yield of vegetables ability of non-aflatoxigenic strains to prevent aflatoxin production by in the Northeast subsequent challenge with toxigenic A. flavus strains was assessed in 4 G. S. ABAWI (1), C. H. Petzoldt (1), B. K. Gugino (2), J. A. LaMondia (3) experiments. Non-aflatoxigenic strain K49 effectively prevented toxin (1) Cornell University, Geneva, NY, U.S.A.; (2) The Pennsylvania State production at various inoculation levels in 3 experiments. K49 also was University, University Park, PA, U.S.A.; (3) CT Agric. Exp. Station, Windsor, evaluated alongside the widely used biocontrol strains NRRL 21882 (Afla- CT, U.S.A. Guard®) and AF36 for prevention of aflatoxin and CPA production by strains Phytopathology 101:S1 K54 and F3W4. K49 and NRRL 21882 were superior to AF36 in reducing aflatoxins. K49 and NRRL 21882 produced no CPA, and reduced CPA and Cover crops are used increasingly by growers to improve soil quality, prevent aflatoxin production in a subsequent challenge with F3W4 and K54 by 84– erosion, increase organic matter, and suppress root pathogens and pests. 97% and 83–98%, respectively. In contrast, AF36 inoculation and subsequent However, limited information is available on their use for suppressing challenge with F3W4 reduced aflatoxins by 20% and 93% with K54, but pathogens (Rhizoctonia, Pythium, Fusarium, Thieloviopsis, Pratylenchus, and showed no CPA reduction with F3W4 and only 62% CPA reduction with Meloidogyne) of vegetables grown in the Northeast. Thus, a collaborative K54. Because AF36 produces CPA, high CPA accumulated in corn with project was initiated in 2009 to assess the efficacy of selected cover crops in AF36 alone. Pin-bar wounding and pin-bar inoculation with F. verticillioides suppressing root pathogens of vegetables and improving soil health in NS-2 resulted in FBs levels of 253 and 1087 ppm, respectively. Inoculation research and on-farm field trials in New York, Pennsylvania and Connecticut. with K49 alone or a mixture of K49 and NS-2 reduced FBs level to 0.1 and 27 In NY, strips (4.5 X 60 M) of 9 cover crops (rye grain + hairy vetch, oat, ppm, respectively. AF36 and NRRL 21882 showed similar FBs reduction sudex, forage radish, red clover, rapeseed, buchwheat, wheat, and a fallow trends to K49. NRRL 21882 and K49 are effective in reducing aflatoxins, check) were randomized in 4 fields with 3 replications (3.2 ha total). The CPA and FBs in corn. fields had different management histories resulting in varied levels of pathogen pressure and soil quality. In 2010, cover crop biomass was measured and collected soil samples were assessed for root health (greenhouse bean Managing potato scab and enhancing tuber yield with low rates of fish bioassay), nematode diversity and density, and selected soil health parameters emulsion applied as a pre-plant soil amendment (Cornell Soil Health Test). In general, root rot severity was lowest and yield P. A. ABBASI (1) of snap bean was highest in the field with the highest soil quality. After one (1) Agriculture & Agri-Food Canada, London, Ontario, CANADA year, the cover crops greatly affected root health and bean yield in this trial as Phytopathology 101:S1 well as the microplots and/or on-farm trials conducted in CT and PA. Another Fish emulsion (FE) is an excellent organic soil amendment to enrich soil cycle of evaluations is in progress. microbes and generate disease suppressive conditions against soil-borne diseases such as seedling damping-off, potato scab, and verticillium wilt. Reduction of aflatoxins, cyclopiazonic acid and fumonisins in corn by However, the rates (20,000 L/ha) of FE that provided effective control of biocontrol strains of non-aflatoxigenic Aspergillus flavus potato scab can be too costly for commercial use. The aim of this 3-year field H. ABBAS (1), B. Horn (2), M. Weaver (3), X. Jin (3), C. Abel (4), W. T. Shier (5) study was to see if much lower rates of FE could suppress potato scab and (1) USDA ARS CG & PRU, Stoneville, MS, U.S.A.; (2) National Peanut increase tuber yield. Diluted FE (1000 and 2000 L/ha or 0.05 and 0.1%) was Research Laboratory, USDA, ARS, Dawson, GA, U.S.A.; (3) USDA ARS, applied to the field plots twice a year before planting and after harvesting Biological Control of Pests Research Unit, Stoneville, MS, U.S.A.; (4) potatoes starting in fall of 2007. The high rate of FE (2000 L/ha) consistently USDA-ARS Corn Insects and Crop Genetics Research Unit, Ames, IA, reduced scab severity by 42% in 2008, 57% in 2009, and 44% in 2010; U.S.A.; (5) Department of Medicinal Chemistry, University of Minnesota, reduced the percentage of tubers with deep-pitted scab by 30% in 2008, 51% Minneapolis, MN, U.S.A. in 2009, and 66% in 2010; and increased the percentage of marketable tubers Phytopathology 101:S1 by 21% in 2008, 55% in 2009, and 12% in 2010. Both rates of FE increased Non-aflatoxigenic biocontrol strains of Aspergillus flavus were examined for total tuber yield by 16–19% in 2008, 14–20% in 2009, and 7–11% in 2010. ability to reduce, production in corn of aflatoxins and cyclopiazonic acid FE soil amendment enhanced the numbers of soil bacteria including those of (CPA) by A. flavus and fumonisins (FBs) by Fusarium verticillioides. The potential bio-control agents belonging to the genera Pseudomonas and Bacillus. These results suggest that economically feasible rates of FE applied more frequently can provide disease suppression and enhance tuber yield. Next step is to monitor the lasting impact of these disease suppressive The abstracts are published as submitted. They were formatted but not edited conditions on continuous potatoes without any further FE application. at the APS headquarters office. Vol. 101, No. 6 (Supplement), 2011 S1 Effect of arbuscular mycorrhizae on aphid infestation of wheat Comparison of endophytic Undifilum DNA and swainsonine content on M. ABDELKARIM (1), B. H. Ownley (1), W. E. Klingeman (1), K. D. locoweeds Gwinn (1) J. ACHATA BOTTGER (1), R. Creamer (1), D. Gardner (2) (1) University of Tennessee, Knoxville, TN, U.S.A. (1) NMSU, Las Cruces, NM, U.S.A.; (2) USDA-ARS, Logan, UT, U.S.A. Phytopathology 101:S2 Phytopathology 101:S2 In greenhouse-grown pots of wheat serendipitously infested with bird cherry Locoweeds are toxic species of Astragalus and Oxytropis, associated with the oat aphid, Rhopalosiphum padi, the aphids preferred non-mycorrhizal endophytic fungus Undifilum oxytropis. The fungus produces swainsonine, an treatments over treatments with arbuscular mycorrhizal (AM) fungi. α-mannosidase-inhibiting alkaloid which causes cell damage to mammals Therefore, studies were developed to determine if mycorrhizal infection when ingested. We used real-time PCR to quantify Undifilum DNA (UD) reduced ability of wheat to support a population of R. padi. Two AM fungi from field samples and in vitro grown plants. Amplification of the ribosomal [Glomus intraradices (Gi), Gigaspora margarita (Gm)] were propagated on ITS allowed reliable quantification of UD in plant tissues. UD in in vitro O. sorghum, and non-mycorrhizal sorghum served as a control. After three sericea increased between the first and third week of growth, whereas months, vegetative growth of sorghum was removed, and cultures, both with swainsonine concentration started increasing between the second and fourth and without AM, were mixed 1:1 with growing medium. Wheat (Triticum week. A strong correlation existed between the amount of UD and the aestivum Pioneer ‘26R22’) seed (10/pot) were planted and allowed to grow in swainsonine concentration in plants grown on culture medium during the first the greenhouse for three weeks. Twenty apterous aphids were transferred to four weeks. Addition of polyethylene glycol to the medium significantly each plant. Three pots/treatment were used in Trial 1; six pots/treatment were impaired the plant development, accelerated endophyte colonization (40 pg used in Trial 2. After 5 days, aphids were counted on each plant. Mycorrhizal UD/ng total DNA at Week 2), and increased the swainsonine concentration. treatment had no impact on germination and survival of wheat plants. Number Acidification of the medium resulted in increased plant growth and minimal of aphids/plant was approximately 2.5 times greater on nonmycorrhizal plants swainsonine content. UD ranges were estimated in locoweed populations in than on Gm-colonized plants [Trial 1 (P = 0.0912); Trial 2 (P = 0.0955)]; New Mexico and Colorado and annual cycles were described for swainsonine numbers of R. padi on Gi-colonized plants were intermediate and not different content. Both UD and swainsonine content coincided at their lowest, while from the other treatments. swainsonine concentration was variable when medium or high amounts of endophyte DNA were found. Our findings highlight the reliability of qPCR Multiplex PCR for four Sclerotinia species for studying endophyte colonization and show environmental cues affecting A. W. Abd-Elmagid (1), P. GARRIDO (1), R. M. Hunger (1), H. A. Melouk the swainsonine synthesis in planta. (2), M. Arif (1), C. D. Garzon (1) (1) Dept. of Entomology and Plant Pathology, Oklahoma State University, Kasugamycin in combination with copper or mancozeb for management Stillwater, OK, U.S.A.; (2) USDA-ARS, Dept. Entomology and Plant of walnut blight in California Pathology, Oklahoma State University, Stillwater, OK, U.S.A. J. ADASKAVEG (1), H. Forster (2), L. Wade (3) Phytopathology 101:S2 (1) University of California, Riverside, CA, U.S.A.; (2) University of California, Davis, CA, U.S.A.; (3) Arysta Life Science, Roseville, CA, U.S.A.