bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Sirococcus clavigignenti-juglandacearum on Black Walnut
Authors: Ostry M. E. , Katovich S. , Anderson R. L. 
Published: May 2007

Sirococcus clavigignenti-juglandacearum is killing butternut (Juglans cinerea) throughout North America. Although black walnut (J. nigra) and other Juglans spp. can be infected with artificial inoculations (2), butternut previously was thought to be the only known natural host. In May 1985, a black walnut, 48 cm in diameter with multiple elliptical cankers on the main stem and lower branches, was found by R. L. Anderson in North Carolina. No fruit bodies were present but isolation from cankers characteristic of those found on butternut produced sporulating pure cultures identical to those described for S. clavigignenti-jugland-acearum (1). A large butternut with coalescing, elliptical cankers was located about 45 m from the infected walnut. In spring 1996, in a plantation in southeastern Minnesota, examination of two 20-year-old black walnuts exhibiting branch dieback revealed hyphal pegs and hyaline, two-celled, fusiform conidia identical to those described for S. clavi-gignenti-juglandacearum (1) on 1994 and 1995 branch wood. Isolations from symptomatic twigs resulted in recovery of the fungus in pure culture. Scattered, naturally occurring, infected, mature butternut and butternut saplings with multiple branch and stem cankers were growing throughout the plantation. Severe winter injury of black walnut in southeastern Minnesota the preceding 3 years may have predisposed trees to infection. References: (1) V. M. G. Nair et al. Mycologia 71:641, 1979. (2) M. E. Ostry et al. Gen. Tech. Rep. NC-165, St. Paul, MN: USDA, Forest Service, North Central For. Exp. Stn., 1994.
Natural Epiphytotic of the Rust Puccinia psidii on Melaleuca quin-quenervia in Florida
Authors: Rayachhetry M. B. , Elliott M. L. , Van T. K. 
Published: May 2007

Melaleuca quinquenervia (Cav.) S. T. Blake (melaleuca), a tree of Australian origin, is an invasive weed of natural areas in southern Florida and has been listed as a federal noxious weed. During January 1997, severe incidence of a rust disease was detected on new growth of about 70% of the melaleuca trees over a 2-km strip in Broward and Dade counties. These top-pruned trees were 3 to 5 m tall with bushy appearance and had many new shoots. The rust was observed on melaleuca saplings and trees in a 20-km radius in January through March 1997. Leaf lesions began as chlorotic flecks that expanded, produced spores, and developed into necrotic spots. Infected leaves were severely distorted. Branches were severely defoliated and succulent twigs were often girdled by lesions, causing dieback of the new growth. Yellow uredinia were observed on all young leaves and some petioles and twigs. Urediniospore morphology and dimensions (17 to 27 × 15 to 24 µm) are consistent with the description of Puccinia psidii G. Wint. (1) and the University of Florida's herbarium material of P. psidii on Pimenta dioica (L.) Merr. (allspice) (2). An inoculation test was conducted with 40-cm-tall melaleuca seedlings. Fully expanded leaves and terminals of these seedlings were brushed or sprayed with freshly collected urediniospores, covered with plastic bags, and placed in a growth chamber maintained at 16°C (night) and 26°C (day) with a corresponding 12-h light cycle for 72 h. The plastic bags were then removed and the seedlings maintained in high humidity and ambient temperatures in a shadehouse. Typical symptoms and sporulation occurred after 10 and 12 days, respectively, following inoculation. Although P. psidii has been recorded on 11 genera in Myrtaceae in the Americas (1,2), including melaleuca, an epiphytotic of this magnitude on melaleuca has not been reported. A different race of P. psidii has been suspected to cause sudden epiphytotics on Pimenta officinalis Lindl. in Jamaica (1). Further research related to host range is warranted to determine the specificity of P. psidii, as this rust may have potential as a microbial biological control agent of melaleuca. References: (1) G. F. Laundon and J. M. Waterson. C.M.I. Descriptions of Pathogenic Fungi and Bacteria No. 56, 1965. (2) R. B. Marlatt and J. W. Kimbrough. Plant Dis. Rep. 63:510, 1979.
Net Blotch and Necrotic Warts Caused by Streptomyces scabies on Pods of Peanut (Arachis hypogaea)
Authors: de Klerk A. , McLeod A. , Faurie R. , van Wyk P. S. 
Published: May 2007

Peanut (Arachis hypogaea L.) grown in rotation with potato (Solanum tuberosum L.) in the Northern Cape Province and at one locality in the Free State Province, South Africa, have developed unusual pod symptoms since the 1994 to 1995 season. Symptoms ranged from a net blotch with scattered lesions to dark brown, necrotic, wartlike lesions on the cv. Sellie. Streptomyces scabies (2) was consistently isolated from both types of lesions. Pathogenicity was confirmed in greenhouse tests. Inoculum was prepared by growing colonies on yeast malt extract agar for 21 days. Ten milliliters of sterile, distilled water was poured over the colonies of two different isolates and lightly scraped with a sterile needle. Separate sets of sterile soil were amended with spore suspensions of different isolates at a rate of 10 ml/kg and thoroughly mixed. Seeds of cv. Sellie and minitubers of potato cv. BP1 were planted in infested soil in 3-kg plastic bags. Uninfested soil served as controls. Each set of pots for both peanut and potato had three replications. Pots were kept in a glasshouse at 27°C for 12 weeks. Plants were lifted, disease development recorded, and infected plant parts prepared for reisolation on antibiotic-amended water/ agar according to the protocols of Loria and Davis (3). Both lesion types recorded under field conditions developed on peanut pods in the glasshouse upon reinoculation. Incidence ranged between 2 and 3 pods out of 8 to 10 pods per plant while minitubers were nearly 100% infected. Streptomyces scabies was isolated from lesions on both peanut and potato. Net blotch caused by an unknown Streptomyces sp. is a significant problem on peanut pods in Israel (1). However, the species found in Israel was not identified and could be different from the one reported here, according to Y. Barash (Tel Aviv University, personal communication). This is a first report of S. scabies being pathogenic on peanut in South Africa. References: (1) Y. Barash et al. (In Hebrew.) Hassadeh 72:688, 1992. (2) D. H. Lambert and R. Loria. Int. J. Syst. Bacteriol. 39:387, 1989. (3) R. Loria and J. R. Davis. Streptomyces scabies. Pages 114-119 in: Laboratory Guide for Identification of Plant Pathogenic Bacteria. 2nd ed. N. W. Schaad, ed. American Phytopathological Society, St. Paul. MN, 1988.
First Report of Cowpea Aphid-Borne Mosaic Potyvirus from Cowpeas Grown Commercially in the U.S.
Authors: Kline A. S. , Anderson E. J. 
Published: May 2007

Cowpea aphid-borne mosaic potyvirus (CABMV) is one of several seed-borne viruses known to limit cowpea (Vigna unguiculata (L.) Walp. subsp. unguiculata) production in Africa, Europe, and Asia, but CABMV has not been reported on commercially grown cowpeas in the United States (1). However, a sesame (Sesamum indicum L.)-infecting isolate of CABMV was recently characterized from plants growing near cowpea introduction plots in Georgia (2). In February 1997, we received samples of three seed lots of cowpea cv. Chinese Red that had been harvested in southern Texas during 1996. Approximately 28% of the plants grown from these seed lots expressed strong mosaic symptoms on primary and trifoliate leaves. Viruslike symptoms were reproduced following mechanical transmission to plants of Chinese Red cowpea, Nicotiana benthamiana, and soybean (Glycine max L.) cv. Lee. When Coronet and Pinkeye Purple Hull-BVR cowpeas were inoculated with sap extracts from symptomatic Chinese Red plants, chlorotic lesions developed on inoculated leaves, but only Coronet plants supported symptomless systemic infections. Similarly inoculated plants of Chenopodium quinoa (L.) and common bean (Phaseolus vulgaris L.) cvs. Pinto and Black Valentine developed localized chlorotic lesions. In Ouchterlony gel diffusion assays, extracts from symptomatic cowpea plants did not react with antisera to blackeye cowpea mosaic potyvirus (BlCMV), cucumber mosaic cucu-movirus (CMV), southern bean mosaic sobemovirus, cowpea mosaic comovirus, cowpea severe mosaic comovirus, or cowpea chlorotic mottle bromovirus. In the indirect enzyme-linked immunosorbent assay, sap extracts from symptomatic plants reacted with antiserum to CABMV, giving OD values at A405 of 0.10 to 0.25, and reacted weakly with antiserum to BlCMV, with OD values at A405 less than 0.035. Extracts from healthy control plants gave OD values at A405 less than 0.010. No positive reactions were obtained with antisera to bean yellow mosaic potyvirus, peanut mottle potyvirus, soybean mosaic potyvirus, or CMV. To our knowledge, this is the first report of CABMV in commercially grown cowpea from the U.S. References: (1) A. G. Gillaspie et al. Plant Dis. 79:388, 1995. (2) H. R. Pappu et al. Arch. Virol. 142:1, 1997.
Daikon (Raphanus sativus cv. longipinnatus) as a Host of Alternaria brassicae in California
Authors: Koike S. T. , Molinar R. H. 
Published: May 2007

In the spring of 1997, commercial plantings of daikon or Chinese radish (Raphanus sativus L. cv. longipinnatus) in the San Joaquin Valley, Fresno County, were damaged by a disease previously undocumented in California. Symptoms consisted of small (2 to 5 mm diameter), circular to oblong, brown to light tan leaf spots that contained concentric rings. Following rains in January, leaf spots proliferated, coalesced, and resulted in significant necrosis of foliage. An Alternaria species with conidia with prominent beaks and spores produced singly or in chains of two was consistently observed on and isolated from the host. Conidia from naturally infected daikon leaves had mean dimensions of 190.1 × 23.1 μm, with a mean beak length of 60.0 μm. The isolates were identified as Alternaria brassicae (2). Pathogenicity was confirmed by culturing six representative isolates on sterilized 20% V8 juice solution for 14 days under a 12 h light/12 h dark cycle, filtering the suspensions through cheesecloth, adjusting spore concentrations to 25,000 conidia per ml, and spraying suspensions onto 4-week-old seedlings of daikon cvs. April and Summer. Plants were incubated in a humid chamber for 48 h and then maintained in a greenhouse. After 5 days, leaf spots similar to the original symptoms developed on all inoculated plants. The pathogen was reisolated and identified as A. brassicae. Control plants sprayed with distilled water remained symptomless. The inoculation test was repeated and results were the same. With the method described above, daikon isolates were also inoculated onto the following A. brassicae hosts (1): radish (Raphanus sativus L. cv. EXCO 517), broccoli (Brassica oleracea L. subsp. botrytis cv. Greenbelt), Chinese cabbage (Brassica campestris L. subsp. pekinensis cv. Cha-Cha), and broccoli raab (Brassica rapa L. subsp. rapa cv. Spring Raab). After 5 (radish) to 12 (other hosts) days, similar leaf spots developed on all inoculated plants and A. brassicae was reisolated and identified. Control plants sprayed with distilled water remained symptomless. These inoculations were repeated and results were the same. For California, this is the first report of black spot caused by A. brassicae on commercially grown daikon. References: (1) S. T. Koike. Plant Dis. 81:552, 1997. (2) E. G. Simmons. Mycotaxon 55:55, 1995.
First Report of Powdery Mildew, Caused by an Oidium sp., on Poinsettia in California
Authors: Koike S. T. , Saenz G. S. 
Published: May 2007

In December 1996 and January 1997, powdery mildew was observed on potted poinsettia (Euphorbia pulcherrima Willd. ex Klotzsch) plants in Monterey County, CA. Mycelia were observed on stems, petioles, mature and immature leaves, and bracts. Severely diseased leaves became twisted and bent and senesced prematurely. The white mycelia were conspicuous, epiphytic, and amphigenous; hyphae measured 4.6 to 6.9 μm in diameter. Growth initially was in patches but eventually became effused. Appressoria were slightly lobed to lobed and sometimes opposite. Conidiophore foot cells were cylindrical, sometimes bent at the base, and slightly flexuous to flexuous. Foot cells measured 30.0 to 46.2 μm × 5.8 to 6.9 μm and were followed by one to two shorter cells. Conidia were cylindrical to slightly doliform and measured 25.4 to 32.3 μm × 11.6 to 18.5 μm. The length-to-width ratios of conidia generally were greater than 2.0. Conidia were produced singly, placing the fungus in the Pseudoidium-type powdery mildew group. Conidia germinated at the ends, and no fibrosin bodies were observed. Cleistothecia were not found. The fungus was identified as an Oidium species. Pathogenicity was demonstrated by gently pressing infected leaves having abundant sporulation onto leaves of potted poinsettia plants (cvs. Freedom Red, Peter Star Marble, and Nutcracker White), incubating the plants in a moist chamber for 48 h, and then maintaining plants in a greenhouse. After 12 to 14 days, powdery mildew colonies developed on the inoculated plants, and the pathogen was morphologically identical to the original isolates. Uninoculated control plants did not develop powdery mildew. This is the first report of powdery mildew on poinsettia in California. This fungus appears similar to Microsphaera euphorbiae but has longer, slightly flexuous foot cells that do not match the description for M. euphorbiae (1,2). An alternative identification would be Erysiphe euphorbiae; however, there are no available mitosporic descriptions for morphological comparisons (1,2). In the United States, powdery mildew of poinsettia previously has been reported in various states in the Pacific Northwest, Midwest, and Northeast. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN.
First Report of Plasmodiophora brassicae on Cabbage in Eastern North Carolina
Authors: Cubeta M. A. , Cody B. R. , Williams P. H. 
Published: May 2007

Clubroot, caused by Plasmodiophora brassicae Woronin, has occurred for at least 50 years in three counties in northwestern North Carolina, but has not been reported previously from eastern North Carolina, where most commercial cabbage is produced. In the fall of 1995, clubroot was observed in a direct seeded, commercial cabbage field in Plymouth, NC. Diseased cabbage plants were stunted and roots exhibited clublike swellings. Clubs were randomly harvested from roots of five plants to obtain a composite isolate to determine which race(s) of P. brassicae are infecting cabbage in eastern North Carolina. Three experiments were conducted, using the procedure of Williams (2). Four replicates of 10, 1-week-old seedlings of eight different crucifer cultivars were inoculated by dipping in a spore suspension (1 × 108 cysts/ml) of P. brassicae and planted in pasteurized potting mix. Seedlings dipped in sterile water served as controls. Inoculated seedlings were incubated in a greenhouse at 18 to 28°C for 6 to 8 weeks and assessed for clubroot incidence and severity. The isolate of P. brassicae from eastern North Carolina was most virulent on cabbage (Brassica oleracea var. capitata cv. Jersey Queen), collard (B. oleracea var. acephala cv. Vates), and wild mustard (B. nigra); moderately virulent on canola (B. napus cv. Brutor) and rutabaga (B. napus cvs. Laurentian and Wilhelmsburger); and least virulent on cabbage (cv. Badger Shipper). Canola (B. napus cv. Nevin) and control seedlings were not infected and exhibited no symptoms. Similar results were obtained for all experiments. Based on these results, the isolate of P. brassicae from eastern North Carolina was designated as race 6 and pathotype 5 according to Williams (2) and Some (1), respectively. However, further experiments with single-cyst-derived isolates from individual clubs obtained from different geographic locations are needed to accurately characterize field populations of P. brassicae on cabbage in eastern North Carolina. References: (1) A. Some et al. Plant Pathol. 45:432, 1996. (2) P. H. Williams. Phytopathology 56:624, 1966.
Rust Disease of Oregano and Sweet Marjoram in California
Authors: Koike S. T. , Subbarao K. V. , Roelfs A. P. , Hennen J. F. , Tjosvold S. A. 
Published: May 2007

In 1996 and 1997, a rust disease was detected on commercial, fieldgrown oregano (Origanum vulgare) and sweet marjoram (Origanum majorana) in coastal California. Symptoms on both plants were similar and mostly consisted of small (2 to 5 mm in diameter), circular, brown, necrotic leaf spots that developed cinnamon brown pustules in the center of the spot or in concentric groups on the spot periphery. Pustules sometimes developed without spots. On sweet marjoram, leaf spots were sometimes surrounded by a chlorotic halo. Teliospores were not detected on either host. Ellipsoidal urediniospores measured 22 to 25 μm by 19 to 22μm and contained 2 to 3 germ pores in an equatorial configuration. The rust was identified as Puccinia menthae. Pathogenicity was tested by depositing urediniospores onto leaves of healthy plants and then incubating plants in a humidity chamber for 48 h. Urediniospores from oregano infected Italian (Origanum× majoricum), Sicilian (Origanum × marjorana), trailing (O. prostrata), and Greek (O. heracleoticum) oregano, and sweet marjoram. Urediniospores from sweet marjoram infected sweet marjoram and the one oregano tested, Italian oregano. With all inoculations, both symptoms and fungal fruiting bodies were similar to those observed in the field. Neither the oregano nor the sweet marjoram isolates infected spearmint (Mentha spicata), which is consistent with previous studies (1,2). This is the first report of a rust disease of oregano and sweet marjoram in California. Rust significantly reduced the quality and yield of both crops. References: (1) J. T. Fletcher. Trans. Br. Mycol. Soc. 46:345, 1963. (2) M. Wilson and D. M. Henderson. 1966. British Rust Fungi, Cambridge University Press, Cambridge.
First Report of Diaporthe phaseolorum var. meridionalis on Soybean Seeds from Ghana
Authors: Asante S. N. A. , Wolffhechel H. , Neergaard E. de 
Published: May 2007

Fifty-nine soybean samples (Glycine max) of various varieties, grown in various agro-ecological zones of Ghana, and harvested in 1995 and 1996, were collected during May through June 1996 and sent to Denmark for analysis. Seed samples were analyzed by the blotter method: seeds were placed on three layers of moistened blotter paper in petri dishes, 10 seeds per dish, 200 or 400 seeds per sample. The seeds were incubated for 7 days at 22 ± 2°C, exposed to alternating cycles of 12 h NUV-light and 12 h darkness. Subsequently, they were analyzed microscopically for fungal infection. Phomopsis spp. were detected in 68% of the samples, at infection levels ranging from 0.25 to 21.0% (mean 3.4%). One to five isolates of Phomopsis spp. were selected at random and cultured on potato dextrose agar acidified to pH 4.5 with 90% lactic acid (APDA) for identification to species. Isolates were cultured on APDA, with and without sterile soybean stem pieces, under either NUV-light/darkness or artificial daylight/darkness cycles. Of 103 isolates, 101 isolates produced only pycnidia and were identified as P. longicolla T. W. Hobbs based on the production of aggregated pycnidia with prominent beaks (2). Seventy-seven of these isolates produced only alpha conidia whereas 24 isolates produced both alpha and beta conidia, which differs from the description by Hobbs et al. (2). Two isolates from one seed sample produced perithecia but no pycnidia. Perithecia were evenly scattered in the colony, 200 to 350 × 250 to 400 μm, and had a beak of 900 to 1500 μm. Apical beak width was 60 to 110 μm, basal beak width 70 to 120 μm. Asci were 25.0 to 37.5 × 5.0 to 7.5 μm. Ascospores were two-celled, biguttulate in each cell, and 10.0 to 12.5 × 2.5 to 4.0 μm. Based on the description by Fernández and Hanlin (1), these isolates were identified as Diaporthe phaseolorum (Cooke & Ellis) Sacc. var. meridionalis Fernández (DPM), the causal agent of southern stem canker of soybean, which has not previously been reported from any African country. Ten 14-day-old soybean seedlings were inoculated with an isolate identified as DPM by the toothpick method (3) and two seedlings inoculated with sterile toothpicks served as controls. Local expanding lesions formed after 1 week on all plants at the point of inoculation with DPM; 2 weeks after inoculation, the pathogen was reisolated from all lesions by plating stem pieces, surface sterilized in 1% NaOCl, on APDA. In control plants no lesions were seen and no mycelial growth occurred from stem pieces plated on APDA. References: (1) F. A. Fernández and R. T. Hanlin. Mycologia 88:425, 1996. (2) T. W. Hobbs et al. Mycologia 77:535, 1985. (3) B. L. Keeling. Phytopathology 72:807, 1982.
Banana Streak Badnavirus and Cucumber Mosaic Cucumovirus in Farmers' Fields in Zanzibar
Authors: Vuylsteke D. R. , Hughes J. d'A. , Rajab K. 
Published: May 2007

Symptoms resembling those of viral leaf streak disease, caused by banana streak badnavirus (BSV), were observed in May 1998 on two banana (Musa spp.) landraces grown from farmer-collected propagules in a farmer's field at Kiboje Uchukuni, Zanzibar. Those showing symptoms were “French plantain” cv. Mzuzu and “Cavendish” banana cv. Mtwike. Leaf symptoms were expressed as chlorotic streaks and blotches. Leaf samples were indexed by immunosorbent electron microscopy with BSV and cucumber mosaic cucumovirus (CMV) antibodies, using partially purified preparations (2). The two landraces tested positive for BSV, corroborating the occurrence of BSV in Zanzibar. In addition, cv. Mtwike was found to be coinfected with CMV. No other viruslike particles were seen by electron microscopy. Although BSV has been reported in Zanzibar (1), it was only from symptoms in the Musa field genebank at Kizimbani Research Station. BSV has been found in many Musa collections worldwide, particularly in the widely grown cv. Mysore. This report confirms the presence of BSV in farmers' fields and is also the first report of CMV infecting banana in Zanzibar. References: (1) A. J. Dabek and J. M. Waller. Trop. Pest Management 36:157, 1990. (2) M. Diekmann and C. A. J. Putter. Musa spp. FAO/IPGRI Technical Guidelines for the Safe Movement of Germplasm No. 15. FAO/IPGRI, Rome, Italy, 1996.