First Report of Dieback Caused by Lasiodiplodia theobromae in Strawberry Plants in Korea

Dieback in strawberry (Seolhyang cultivar) was first observed during the nursery season (June to September) in the Nonsan area of Korea in the years 2012 and 2013. Initial disease symptoms included dieback on runners, as well as black rot on roots, followed by wilting and eventually blackened, necrotic discoloration in the crowns of daughter plants. A fungus isolated from the diseased roots, runners, and crowns is close to Lasiodiplodia theobromae based on morphological characteristics. Analysis of a combined dataset assembled from sequences of the internal transcribed spacer and translation elongation factor 1-alpha genes grouped nine fungal isolates with the type strain of L. theobromae. The isolates showed strong pathogenicity on strawberry cultivars Kumhyang, Seolhyang, and Akihimae, fulfilling Koch's postulates. Based on these results, the pathogen responsible for dieback on strawberry plants in Korea was identified as L. theobromae.

Cladosporium cladosporioides and C. tenuissimum Cause Blossom Blight in Strawberry in Korea

Blossom blight in strawberry was first observed in a green house in Nonsan, Damyang, and Geochang areas of Korea, between early January to April of 2012. Disease symptoms started as a grey fungus formed on the stigma, which led to the blossom blight and eventually to black rot and necrosis of the entire flower. We isolated the fungi purely from the infected pistils and maintained them on potato dextrose agar (PDA) slants. To test Koch's postulates, we inoculated the fungi and found that all of the isolates caused disease symptoms in the flower of strawberry cultivars (Seolhyang, Maehyang, and Kumhyang). The isolates on PDA had a velvet-like appearance, and their color ranged between olivaceous-brown and smoky-grey to olive and almost black. The intercalary conidia of the isolates were elliptical to limoniform, with sizes ranging from 5.0~10.5 x 2.5~3.0 microm to 4.0~7.5 x 2.0~3.0 microm, respectively. The secondary ramoconidia of these isolates were 0- or 1-septate, with sizes ranging betweem 10.0~15.0 x 2.5~3.7 microm and 8.7~11.2 x 2.5~3.2 microm, respectively. A combined sequence analysis of the internal transcribed spacer regions, partial actin (ACT), and translation elongation factor 1-alpha (TEF) genes revealed that the strawberry isolates belonged to two groups of authentic strains, Cladosporium cladosporioides and C. tenuissimum. Based on these results, we identified the pathogens causing blossom blight in strawberries in Korea as being C. cladosporioides and C. tenuissimum.

Genetic Diversity and Pathogenicity of Cylindrocarpon destructans Isolates Obtained from Korean Panax ginseng

We analyzed the genetic diversity of Cylindrocarpon destructans isolates obtained from Korean ginseng (i.e., Panax ginseng) roots by performing virulence tests and nuclear ribosomal gene internal transcribed spacer (ITS) and mitochondrial small subunit (mt SSU) rDNA sequence analysis. The phylogenetic relationship analysis performed using ITS DNA sequences and isolates from other hosts helped confirm that all the Korean C. destructans isolates belonged to Nectria/Neonectria radicicola complex. The results of in vivo and ex vivo virulence tests showed that the C. destructans isolates could be divided into two groups according to their distinctive difference in virulence and the genetic diversity. The highly virulent Korean isolates in pathogenicity group II (PG II), together with foreign isolates from P. ginseng and P. quinquefolius, formed a single group. The weakly virulent isolates in pathogenicity group I, together with the foreign isolates from other host plants, formed another group and exhibited a greater genetic diversity than the isolates of PG II, as confirmed by the mt SSU rDNA sequence analysis. In addition, as the weakly virulent Korean isolates were genetically very similar to the foreign isolates from other hosts, they were likely to originate from hosts other than the ginseng plants.

Laboratory Evaluation of Automated Urine Analyzer ComboStick Reader 720(R) and Reagent Strip ComboStick 10 / 임상검사와정도관리

BACKGROUND: The ComboStick Reader 720(R)(DFI Co., Ltd. Korda) is a newly developed automated urine analyzer. The objective of this analysis was to evaluate the analytical performance of the Combostick Reader 720 and ComboStick 10 reagent strips and to compare the results using the Uriscan Pro II and Uriscan Gen 10 SGL strips (YD Diagnostics, Korea). METHODS: The Dipstick urinalyses were performed on a ComboStick Reader 720(R) using ComboStick 10 strips and on a Uriscan Pro II(R) using Uriscan 10 SGL strips. Precision was evaluated with commercial control materials. The sets of results were analyzed for concordance with weighted kappa values or intraclass correlation coefficients (ICCs). The microscopic urine analysis was carried out to confirm the results from both automated urine analyzers. Agreement between the dipstick methods and the microscopic method was evaluated by kappa values and the McNemar test. RESULTS: Within and between-run precisions of the ComboStick Reader 720(R) were 90.0% to 100%. A comparison of results from 1,700 urine samples using the ComboStick Reader 720(R) and Uriscan Pro II(R) revealed a very high concordance rate of > or = 91.0% on consideration of neighboring blocks for all analytes of the dipstick urinalysis. There was a good association between the microscopic method and the dipstick methods of the two automated urine analyzers. The ComboStick Reader 720(R) revealed a statistically higher degree of agreement for leukocytes. CONCLUSIONS: The ComboStick Reader 720(R) and ComboStick 10 strips showed good precisions and revealed a statistically significant agreement with the Uriscan Pro II(R) and Uriscan 10 SGL strips. For leukocytes, the ComboStick Reader 720(R) was superior to the Uriscan Pro II(R) in comparing the agreement between the microscopic and dipstick methods. The overall performance of the ComboStick Reader 720(R) and ComboStick 10 strips were satisfactory.