bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Hop Powdery Mildew in the Pacific Northwest
Authors: Ocamb C. M. , Klein R. , Barbour J. , Griesbach J. , Mahaffee W. 
Published: May 2007

Hop powdery mildew (HPM) was first observed in commercial hop (Humulus lupulus L.) fields in Washington State on 10 June 1997 near Toppenish in the Yakima Valley. The disease appeared throughout the valley in 1997; by mid-July, scattered fields throughout the Yakima growing area reported HPM. Approximately 2,000 of 30,000 acres in production were not harvested in 1997 due to HPM. The pathogen apparently perennated in buds, and flagshoots originating from infected buds were observed during March and April 1998 at various locations throughout the Yakima Valley. During the 1999 growing season, the majority of hop acreage in Washington State was affected, and most fields planted to susceptible cultivars contained at least one infected plant. HPM was initially discovered in southern Idaho during early July 1998, in two adjacent fields of hops in Canyon County. HPM was found ≈644 km (400 miles) north in another hop-growing region of Idaho, Boundary County, during mid-July 1998. HPM eventually was observed in more than 20 Idaho hop fields. The initial discovery of HPM in Oregon's Willamette Valley was made during late-July 1998, in two neighboring hop fields. By the end of the growing season, HPM was observed in nine commercial fields representing 3.7% of the hop production acreage in Oregon. Affected cultivars include Brewer's Gold, Chinook, Cluster, Columbus/Tomahawk, Eroica, Fuggle, Galena, Golding, Liberty, Olympic, Perle, Symphony, Tettnanger, Willamette, and Zeus. Infected basal leaves of bines had small whitish circular spots on adaxial surfaces. In some cases, blisters preceded direct observation of the fungus. Cones also were infected, appearing stunted and malformed. The pathogen usually was visible on infected cones but sometimes was found only under overlapping bracts. Cleistothecia have not been observed in the field to date. Conidia were transferred to leaf disks (12 mm diameter) excised from greenhouse-grown cv. Galena hop plants. Inoculated leaf disks were incubated on moistened filter paper in glass petri dishes at 20°C with illumination provided for a 12 h day by two cool-white fluorescent bulbs. HPM lesions with chains of unicellular, barrel-shaped conidia (30 to 36 × 15 to 18 μm) were visible within 7 days. The causal agent was identified as Sphaerotheca macularis (Wallr.:Fr.) Lind (synonym S. humuli (DC.) Burrill) on the basis of conidial shape and size as well as host range (1). Reference: (1) D. J. Royle. 1978. Powdery mildew of the hop. Pages 381–409 in: The Powdery Mildews. D. M. Spencer, ed. Academic Press, New York.
First Report of Transmission of Verticillium dahliae by Infested Manure in Olive Orchards in Andalucia (Southern Spain)
Authors: Lopez-Escudero F. J. , Blanco-Lopez M. A. 
Published: May 2007

Olive (Olea europaea L.) is a traditional tree crop in Andalucia, southern Spain. Over the past several years, new plantations have been established in areas where other crops susceptible to Verticillium dahliae, such as cotton, sunflower, and vegetables, usually have been grown. Surveys performed from 1989 to 1996 showed that Verticillium wilt, caused by V. dahliae, has become the most important soilborne fungal disease affecting young olive trees in this area (3). Manure is sometime used as a soil amendment before and after tree planting to increase organic matter content of soil. In 1996, manure was used to establish an olive plantation in Sevilla Province. The dung came from sheep fed on harvested fields of cotton, sunflower, and sugar beet. The remaining manure was left in a pile in the field. In 1998, 2 years after planting, many olive plants in the field showed Verticillium wilt symptoms. Samples were collected from the soil and the surfaces and core of the manure pile for isolation and quantitative assessment of the pathogen. Wet-sieving and sodium pectate agar selective medium were used (1). V. dahliae was isolated from both the manure and soil. Mean inoculum density in the samples taken from the pile and soil were 8.4 and 7.2 microsclerotia per gram, respectively. Although it has been demonstrated that V. albo-atrum survives the digestive process in animals (2), this is the first report on dispersion of V. dahliae by manure from sheep fed on infested stubble. The use of manure infested with V. dahliae may contribute to pathogen dispersion and to the increase in Verticillium wilt incidence in olive orchards in Andalucia. Because animal manure is a potential means for V. dahliae transmission, it is recommended that before manure is applied tests be performed, when feasible, to make sure it is pathogen-free. References: (1) E. J. Butterfield and J. E DeVay Phytopathology 67:1073, 1977. (2) H. C. Huang et al. Plant Dis. 70:218, 1986. (3) M. E. Sanchez Hernandez et al. Eur. J. Plant Pathol. 104: 347, 1998.
First Report of a Fruit Rot of Pumpkin Caused by Acidivorax avenae subsp. citrulli in Georgia
Authors: Langston D. B. , Walcott R. D. , Gitaitis R. D. , Sanders F. H. 
Published: May 2007

In September 1998, a fruit rot was reported affecting pumpkin (Cucurbita pepo) in a commercial field in Terrell Co., Georgia. Symptoms on the surface of fruit occurred as round, necrotic spots or cracks a few millimeters in diameter. With age, the tissue surrounding these lesions became soft and wrinkled. A soft rot expanded into the flesh of the pumpkin, originating from the lesions observed on the surface. In time, infected pumpkins totally collapsed. V-shaped, necrotic lesions occurred at the margin of the leaf and extended inward toward the mid-rib. Samples were collected from the field and bacteria were isolated from fruit and leaf lesions onto King's medium B (1). The bacterium isolated was rod shaped, gram negative, nonflourescent, oxidase positive, Tween 80 positive, carboxymethyl cellulose positive, β-OH butyrate positive, and malonate negative. The bacterium reacted positively with polyclonal antibodies specific for the watermelon fruit blotch pathogen Acidivorax avenae subsp. citrulli and was identified as A. avenae subsp. citrulli by MIDI (Microbial Identification System, Newark, DE) according to statistical analysis of fatty acid data. Results from polymerase chain reaction (PCR) amplification of the bacterium isolated from pumpkin yielded 360-bp fragments that, when digested with the restriction enzyme HaeIII, had DNA banding patterns identical to those of stock A. avenae subsp. citrulli DNA. Koch's postulates were completed successfully with 2-week-old watermelon seedlings. This is the first report of A. avenae subsp. citrulli causing fruit rot of pumpkin in Georgia. Reference: (1) E. O. King et al. J. Lab. Clin. Med. 44:301, 1954.
First Report of Ralstonia (Pseudomonas) solanacearum Infecting Pot Anthurium Production in Florida
Authors: Norman D. J. , Yuen J. M. F. 
Published: May 2007

Xanthomonas campestris pv. dieffenbachiae is a common pathogen of pot anthurium production in Florida. While X. campestris pv. dieffenbachiae was isolated from systematically infected plants with chlorotic, necrotic, and wilted leaves, a fluidal, beige bacteria was occasionally isolated on nutrient agar (Difco, Detroit, MI), as opposed to the common, yellow pigmented Xanthomonas sp. Distinction in the symptomology of plants systematically infected with a Xanthomonas sp. or this new bacterium could not be made. Three isolates were obtained of this unidentified bacterium from leaves and stems of three separate plants. With FAME (fatty acid methyl esters) analysis, using MIDI (Microbial Identification System, software version TSBA 3.90 [Newark, DE]), these isolates were classified as Ralstonia (Pseudomonas) solanacearum (syn. Burkholderia solanacearum) with a mean similarity indice of 0.895. Isolates were found to be gram negative, oxidase negative, catalase positive, motile, strictly aerobic, and metabolically classified as biovar 1; they accumulated poly-β-hydroxybutyrate and produced a hypersensitive response on tobacco within 24 h. A characteristic fluidal, white growth with a distinctive, red, swirling, egg-shaped, pigmentation pattern was observed on triphenyltetrazolium chloride medium. Further confirmation of identity as R. solanacearum was obtained by polymerase chain reaction amplification and electrophoretic analysis with species-specific primers (2), which in all cases produced a 148-bp product along with control strains. The three isolates were inoculated onto three plants of anthurium, tomato, triploid banana, and pothos. Inoculations were done at least twice; plants were inoculated either by stabbing the plant stems with a needle dipped in a suspension of bacteria or by applying 10 ml of a 1 × 108 CFU/ml suspension to the soil of the test plants. Chlorosis, necrosis, and wilt symptoms appeared within 2 weeks on all plant species tested. Recently, pothos (Epipremnum aureum) cuttings imported to Florida from Costa Rica have been implicated as a source of R. solanacearum (1). Imported cuttings of pothos were being grown in hanging baskets over the infected anthuriums. Although no R. solanacearum infections were detected in the pothos, these imported plants are the probable source of the initial inoculum for this disease outbreak on anthuriums. References: (1) D. J. Norman and J. M. F. Yuen. Phytopathology 87:S70, 1997. (2) S. E. Seal et al. Appl. Environ. Microbiol. 58:3751, 1992.
First Report of Aerial Blight Caused by Pythium myriotylum on Tomato in Florida
Authors: Roberts P. D. , Urs R. , McGovern R. J. 
Published: May 2007

In September 1996 and 1997, diseased tomato seedlings were observed with symptoms of an aerial watery rot on leaves, petioles, and stems. Tomato cvs. Sanibel and 10097 from commercial fields in southwest Florida (Collier and Lee counties) and west central Florida (Manatee County) exhibited similar symptoms that occurred at an incidence of 15 to 18% about 4 weeks after transplanting and resulted in plant death. Microscopic examination of symptomatic tissue revealed the presence of mycelium and oogonia typical of Pythium spp. A fungus was consistently isolated from four plants sampled from each site onto a medium selective for Pythium spp. and maintained in pure culture on V8 juice agar at 28°C. The isolates were identified as Pythium myriotylum Drechs. based on the following morphological data: lobate sporangium, 12 to 13 μm wide; vesicle 15.4 to 19.4 μm in diameter; exit tube 54 to 90 μm long, oogonium 23 to 30 μm in diameter; and oospore 21 to 26 μm in diameter (1,2). Pathogenicity tests were conducted with two isolates from diverse regions within Florida by spray inoculating the leaves and shoots of 6- to 8-week-old tomato seedlings with a sporangial suspension of 1 × 104 sporangia per ml. Noninoculated plants served as controls. Plants had 24 h of pre- and post-dark period, day/night temperatures of 28/21°C, a 14-h photoperiod, and near 100% relative humidity in a growth chamber. The foliage of inoculated tomato plants exhibited symptoms identical to those observed in field samples 24 h after inoculation and 100% mortality within 72 h. The reisolated fungus was morphologically identical to the original isolate. Noninoculated plants remained asymptomatic. The unusual rainfall recorded at some sites, such as in Manatee County in September 1997, was 36% higher than the 40-year average and may have contributed to the incidence of this previously undescribed foliar blight. References: (1) Anonymous. C.M.I. Descriptions of Pathogenic Fungi and Bacteria No. 118. (2) T. Watanabe. Pictorial Atlas of Soil Fungi. Lewis Pub., London. p. 71.
First Report of Grapevine Downy Mildew (Plasmopara viticola) in Commercial Viticulture in Western Australia
Authors: McKirdy S. J. , Riley I. T. , Cameron I. J. , Magarey P. A. 
Published: May 2007

Despite the suitability of climate, Western Australia was one of the few grape (Vitis vinifera L.) growing areas free of grapevine downy mildew (Plasmopara viticola (Berk. & M. A. Curtis) Berl. & De Toni in Sacc.). Area freedom had been maintained by restricting the movement of host material and machinery from outside the state and fungicide use in Western Australia vineyards had been considerably less. P. viticola was detected in 1997 in 14 of 15 vines growing at Kalumburu, a remote community in the semi-arid tropics of Western Australia, and was eradicated. In October 1998, grape leaves with oilspots typical of downy mildew were received from a grower in the Swan Valley near Perth, one of the main production areas of Western Australia. Sporangia were hyaline and ellipsoid (14 × 11 μm), were borne on treelike sporangiophores, and were consistent with those described for P. viticola (1). This is the first record of P. viticola in commercial viticulture in Western Australia. A response plan for exotic diseases was activated and after 2 weeks of surveillance the disease was found in 45 of 70 vineyards surveyed of the 280 vineyards in the Swan Valley. Given the extent of spread, eradication of downy mildew was not considered possible. Weather data for August to October 1998 indicated the likelihood of several infection periods from budburst to flowering when the disease was first detected. Crop loss will be considerable in many vineyards. P. viticola was also found in bench-grafted cuttings in pots in leaf consigned from the Swan Valley to several other areas in August 1998. Downy mildew was found in other areas only in association with these consigned vines. An industry code of practice, including hygiene, is being developed to slow the rate of spread of P. viticola in Western Australia. Reference: (1) Anon. C.M.I. Descriptions of Pathogenic Fungi and Bacteria No. 980, 1989.
First Report of Sclerotinia sclerotiorum on Common Ragweed (Ambrosia artemisiifolia) in Europe
Authors: Bohár Gy. , Kiss L. 
Published: May 2007

Common ragweed (Ambrosia artemisiifolia L.) is reported as a host of Sclerotinia sclerotiorum (Lib.) de Bary in North America (2,4), but not in Europe. A Hungarian survey of fungal diseases of ragweed in 1994 did not find sclerotinia rot of common ragweed (A. artemisiifolia var. elatior (L.) Descourt.) (1). In autumn 1998, mature ragweed plants, 1 to 1.5 m tall, were collected from the borders of four sunflower (Helianthus annuus L.) fields in which sclerotinia rot of sunflower was frequently observed during the season, and also from six other roadside sites in Hungary. Ragweed plants exhibiting symptoms characteristic of sclerotinia rot, i.e., wilting foliage and light brown, dry lesions on the stems, were found only near two sunflower fields. Black, round to irregular or oblong sclerotia were also observed on the infected ragweed plants both externally on the stem lesions and internally, in the pith cavity. Sclerotia measured up to 5 mm in diameter and were 5 to 14 mm long. After isolation on potato dextrose agar, the pathogen produced abundant aerial mycelium and large sclerotia characteristic of S. sclerotiorum. To confirm pathogenicity, potted seedlings and mature plants of ragweed were inoculated in the greenhouse with autoclaved wheat grains colonized with mycelia of S. sclerotiorum placed 0.5 to 1 cm from the collar of the test plants. Seedlings were killed in 2 to 3 days while mature plants wilted after 5 to 6 days. In a field test, six mature plants were inoculated by attaching mycelial disks to their stems with Parafilm. These plants wilted 12 to 14 days after inoculation. The pathogen was reisolated from all diseased plants. This is the first report of S. sclerotiorum on common ragweed in Europe. Nonsclerotial mutants of the fungus (3) are being produced to be tested as potential biocontrol agents of common ragweed, which has become not only the most widespread, but also the most important allergenic plant species in Hungary since the early 1990s. References: (1) Gy. Bohár and L. Vajna. Nōvényvédelem 32:527, 1996. (2) G. J. Boland and R. Hall. Can. J. Plant Pathol. 16:93, 1994. (3) G. J. Boland and E. A. Smith. Phytopathology 81:766, 1991.(4) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN.
Lisianthus Crown and Stem Rot Caused by Fusarium avenaceum in Central Italy
Authors: Pecchia S. 
Published: May 2007

Lisianthus (Eustoma russelianum, syn. E. grandiflorum), a member of the Gentian family, is grown in the greenhouse in Italy as a commercial cut-flower crop. Its cultivation is a relatively new industry with high economic potential. However, disease problems have been observed on various greenhouse-planted lisianthus in Central Italy (Tuscany): symptoms of wilting, tan leaf flecks, tan stem discoloration, crown and stem rot, and death. White mycelia and orange sporodochia were also commonly observed on diseased crowns and stems. Fusarium avenaceum isolates were recovered from diseased tissues. Four single-spore isolates were selected for artificial inoculation. Pathogenicity tests were conducted in the greenhouse on 16- to 17-week-old E. russelianum plants, cvs. Mariacki, Echo, and Heidi, by placing a colonized agar plug, or drops of a conidial suspension, at the crown previously wounded with a sterile scalpel. Moist cotton was fastened to the wound site. Control plants were inoculated with sterile agar plugs or drops of sterile, distilled water. Five plants per cultivar and per treatment were used for each isolate. All plants developed typical disease symptoms within 1 or 2 weeks when inoculated with mycelial plugs or conidial suspensions, respectively. Control plants developed no symptoms. Koch's postulates were completed by consistently reisolating the pathogen from inoculated plants. This is the first report of F. avenaceum on lisianthus in Italy and is similar to reports of the disease in California and Florida (1,2). References: (1) S. T. Koike et al. Plant Dis. 80:1429, 1996. (2) R. J. McGovern et al. Phytopathology 87:S64, 1997.
Powdery Mildew of Spearmint Caused by Erysiphe orontii in California
Authors: Koike S. T. , Saenz G. S. 
Published: May 2007

In 1997 and 1998, the white fungal growth of a powdery mildew was observed on leaves and stems of both nursery and landscape spearmint (Mentha spicata) growing in coastal California (Monterey County). Mycelia were conspicuous, amphigenous, and epiphytic with indistinct to nipple-shaped appressoria. Conidiophore foot cells were cylindrical, straight, nonconstricted at the base, 61 to 92 μm × 11 to 14 μm in size, and were followed by 1 to 3 cells. Doliiform conidia, which were borne in chains of at least 3 to 5 conidia, measured 28 to 33 μm × 17 to 22 μm. Catenate conidia had sinuate edge lines. Conidia lacked fibrosin bodies. Upon germination, conidia produced germ tubes that were mostly apically inserted and ended in club-shaped appressoria, which fit Braun's Cichoracearum-type of conidial germination (1). Cleistothecia were not observed. Based on these features, the pathogen was identified as Erysiphe orontii Cast. (1). Pathogenicity was demonstrated by gently pressing diseased leaves onto leaves of potted spearmint, incubating plants in a humidity chamber for 48 h, then maintaining plants in a greenhouse. The powdery mildew that later developed was morphologically identical to the original isolates. While powdery mildew on spearmint has been observed previously in the state, this is the first report of the disease and first characterization of the pathogen for California. Reference: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987.
A Novel Geminivirus of Ipomoea indica (Convolvulacae) from Southern Spain
Authors: Banks G. K. , Bedford I. D. , Beitia F. J. , Rodriguez-Cerezo E. , Markham P. G. 
Published: May 2007

A cutting of Ipomoea indica displaying yellow vein symptoms was collected from Nerja in southern Spain in 1995, rooted, and maintained by vegetative propagation under glasshouse conditions at the John Innes Centre, Norwich. Although this member of the Convolvulaceae is native to the New World, it has escaped from cultivation as an ornamental and has now been naturalized in many tropical and warm temperate regions of the world, such as southern Spain. The same plant was found to host a population of whiteflies that were also brought back to containment facilities, and maintained in colony. Total plant DNA was extracted from the I. indica plant and universal primers for begomovirus A component (1) were used to amplify an approximately 2.8-kb fragment that was cloned and sequenced. The sequence is available in the DDJB, EMBL, and GenBank nucleotide sequence data bases under accession number AJ132548. A GENEMBL search with the complete sequence of the clone showed 70.8% identity to the AC1 gene of Ageratum yellow vein virus (AYVV). A search with the coat protein gene sequence showed highest homology to tomato leaf curl virus from southern India, another monopartite virus. Typical geminivirus vein yellowing symptoms, nucleotide sequence similarity, and EM detection of geminate virus particles strongly suggest that a geminivirus is present in this plant. The low level of homology to other sequenced geminiviruses suggests that it is an uncharacterized Begomovirus sp. With degenerate DNA-B primers (2), no B component has so far been detected. This virus is provisionally named Ipomoea yellow vein virus (IYVV). With techniques already established for identifying Bemisia spp. (3), the whiteflies collected with this Ipomoea plant were confirmed as Bemisia tabaci. Transmission studies to healthy I. indica showed that this whitefly population (named biotype S), the Q biotype from Spain, and the B biotype from Israel were all unable to transmit IYVV to healthy I. indica, tobacco, tomato, or nightshade. This may be due to many years of vegetative propagation of the host plant as an ornamental, resulting in loss of virus transmissibility by insects, which has occurred with Abutilon mosaic virus (AbMV) and honeysuckle yellow vein mosaic virus (HYVMV). This is the first report of a novel geminivirus on I. indica. It highlights the importance of weeds as hosts and potential reservoirs of both viruses and pests. We acknowledge support from the British Council, The Royal Society, BBSRC, and MAFF. References: (1) R.W. Briddon and P. G. Markham. Mol. Biotechnol. 1:202, 1994. (2) M. R. Rojas et al. Plant Dis. 77:340, 1993. (3) R. C. Rosell et al. Ann. Entomol. Soc. Am. 90:575, 1997.