@article{koenning_frye_butler_creswell_2007, title={First report of Phakopsora pachyrhizi on Kudzu (Pueraria montana var. lobata) in North Carolina and increased incidence of soybean rust on soybean in 2006.}, volume={91}, ISSN={["1943-7692"]}, DOI={10.1094/PDIS-91-5-0637A}, abstractNote={ Asian soybean rust, caused by Phakopsora pachyrhizi H. Sydow & Sydow, was first detected in the continental United States in soybean (Glycine max (L.) Merr.) in Louisiana on 6 November 2004 (3) and in kudzu (Pueraria montana var. lobata) in Florida during February 2005 (1). Soybean rust was first confirmed in North Carolina in commercial soybean fields in Brunswick, Columbus, and Robeson counties on 25 October 2005 (2). Subsequently, the disease was detected in soybean in 18 counties, but not in kudzu, even when it was growing adjacent to infected soybean. During 2006, soybean rust was first detected in North Carolina in soybean on 14 September 2006 from a sample from Columbus County that was submitted to the North Carolina State University Plant Disease and Insect Clinic (NCSU-PDIC). Thus, the first detection of soybean rust in North Carolina occurred almost 6 weeks earlier in 2006 than in 2005. Subsequently, in 2006, soybean rust was found in soybean in 42 counties in North Carolina through survey, sentinel plot monitoring, and samples submitted to the NCSU-PDIC. In addition, what appeared to be soybean rust was observed in two samples of kudzu collected on 3 and 6 November 2006 from Moore (35.28313°N, 79.38020°W) and Johnston (35.42742°N, 78.18154°W) counties of North Carolina. The diagnosis of P. pachyrhizi in kudzu was confirmed visually and by ELISA protocol supplied with the EnviroLogix QualiPlate kit (Portland, ME). ELISA tests for each kudzu sample were run in triplicate. PCR was also conducted on infected kudzu samples with a protocol previously reported (1). The PCR master mix that was used came from a dilution scheme based on previous PCR work completed by G. Z. Abad. A total of 24 reactions were run, including four 1-kb molecular markers, four positive controls, four negative controls, and four infected kudzu leaf tissue samples. The results of all diagnostic techniques confirmed the presence of P. pachyrhizi in diseased kudzu. To our knowledge, this is the first report of P. pachyrhizi in kudzu in North Carolina. }, number={5}, journal={PLANT DISEASE}, author={Koenning, S. R. and Frye, J. W. and Butler, S. C. and Creswell, T. C.}, year={2007}, month={May}, pages={637–637} }
 @article{koenning_moore_creswell_abad_palm_mckemy_hernandez_levy_devries-paterson_2006, title={First report of soybean rust caused by Phakopsora pachyrhizi in North Carolina.}, volume={90}, ISSN={["1943-7692"]}, DOI={10.1094/PD-90-0973A}, abstractNote={ Asian soybean rust, caused by Phakopsora pachyrhizi Sydow, has been known to occur in the eastern hemisphere for nearly a century. More recently, it was reported from South America in 2002 and the continental United States in Louisiana in November 2004 (1,2). Subsequently, P. pachyrhizi was confirmed in Alabama, Arkansas, Georgia, Florida, Missouri, Mississippi, South Carolina, and Tennessee in 2004. Surveys conducted in North Carolina in late November 2004 failed to detect this pathogen. Symptoms of the disease were first observed on soybean (Glycine max (L.) Merr.) in North Carolina on 25 October 2005 in farmers' fields in the counties of Brunswick, Columbus, and Robeson. Typical pustules and urediniospores were readily apparent on infected leaves when viewed with a dissecting microscope. Urediniospores were obovoid to broadly ellipsoidal, hyaline to pale yellowish brown with a minutely echinulate thin wall, and measured 18 to 37 × 15 to 24 μm. This morphology is typical of soybean rust caused by P. pachyrhizi or P. meibomiae, the latter is a less aggressive species causing soybean rust in the western hemisphere (1). DNA was extracted from leaves containing sori using the Qiagen DNeasy Plant Mini kit (Valencia, CA). P. pachyrhizi was detected using a real-time polymerase chain reaction (PCR) protocol that differentiates between P. pachyrhizi and P. meibomiae in a Cepheid thermocycler (Sunnyvale, CA) with appropriate positive and negative controls. The PCR master mix was modified to include OmniMix beads (Cepheid). Field diagnosis of P. pachyrhizi was confirmed by the USDA/APHIS on 28 October 2005. Soybean rust was identified in subsequent surveys of soybean fields and leaf samples submitted by North Carolina Cooperative Extension Agents in an additional 15 counties. These samples also were assayed using a traditional PCR protocol and by the enzyme-linked immunosorbent assay protocol included in the EnviroLogix QualiPlate kit (Portland, ME) for soybean rust. Ten soybean specimens from 10 sites were confirmed positive by these methods. Disease was not found on three kudzu samples, although one kudzu sample was adjacent to a soybean field that was positive for P. pachyrhizi. Although soybean rust was eventually detected in 18 North Carolina counties in 2005, no soybean yield loss occurred since the pathogen was detected when more than 80% of the soybean crop was mature. To our knowledge, this is the first report of P. pachyrhizi in North Carolina and the northern most find on soybean in the continental United States in 2005. }, number={7}, journal={PLANT DISEASE}, author={Koenning, S. R. and Moore, A. D. and Creswell, T. C. and Abad, G. Z. and Palm, M. E. and McKemy, J. M. and Hernandez, J. R. and Levy, L. and DeVries-Paterson, R.}, year={2006}, month={Jul}, pages={973–973} }
 @article{koenning_creswell_dunphy_sikora_mueller_2006, title={Increased occurrence of target spot of soybean caused by Corynespora cassiicola in the southeastern United States.}, volume={90}, ISSN={["0191-2917"]}, DOI={10.1094/PD-90-0974C}, abstractNote={ Target spot of soybean (Glycine max (L.) Merr.) caused by Corynespora cassiicola (Berk. & Curt.), although found in most soybean-growing countries, is considered to be a disease of limited importance (1) and has never been reported to cause soybean yield loss in the southeastern United States (2,3). Soybean plants submitted to the North Carolina Plant Disease and Insect Clinic (NCPDIC) in August 2004 from Beaufort, Robeson, Wilson, and Johnston counties, NC had symptoms consistent with target spot. Symptoms consisted of roughly circular, necrotic leaf lesions from minute to 11 mm in diameter, though typically approximately 4 to 5 mm in diameter, and with a yellow margin. Large lesions occasionally exhibited a zonate pattern often associated with this disease. Microscopic examination of the lesions revealed the presence of spores (conidia) typical of C. cassiicola (1). Conidia were mostly three to five septate with a central hilum at the base and ranged in size from 7 to 22 wide × 39 to 520 μm long. Three commercial soybean fields near Blackville, SC (Barnwell County) were severely affected by this disease and it caused premature defoliation. Nineteen of twenty-seven maturity group VII and VIII genotypes in the 2004 Clemson University soybean variety trial near Blackville, SC had visible symptoms of target spot. Heavy rainfall associated with hurricanes during September 2004 probably enhanced the incidence of this disease, and yield suppression due to target spot was estimated at 20 to 40% in some fields. In 2005, 20 of 161 soybean samples submitted to the NCPDIC or collected in surveys from 16 counties were positive for target spot on the basis of microscopic examination. Target spot also was diagnosed in six counties (Baldwin, DeKalb, Elmore, Fayette, Macon, and Pickens) in Alabama and in four additional counties (Bamberg, Hampton, Orange-burg, and Calhoun) in South Carolina in 2005. Records from the NCPDIC indicate that target spot had not been diagnosed on soybean in North Carolina since 1981. The large increase in incidence of target spot in the southeast may be related to changes in weather patterns, changes in pathogen virulence, and/or the introduction of more susceptible host genotypes. }, number={7}, journal={PLANT DISEASE}, author={Koenning, SR and Creswell, TC and Dunphy, EJ and Sikora, EJ and Mueller, JD}, year={2006}, month={Jul}, pages={974–974} }