scholarly journals First Record of Phytophthora nicotianae Causing Leaf Blight on Rhododendron in Greece

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 777-777
Author(s):  
P. Tsopelas ◽  
E. J. Paplomatas ◽  
S. E. Tjamos ◽  
K. Elena

Species of Rhododendron and resulting hybrids are very important hosts of the quarantine pathogen Phytophthora ramorum, since they play a major role in the spread of the pathogen in Europe. However, many other Phytophthora species infect these hosts, causing similar symptoms. Widmer (4) listed 17 Phytophthora species as foliar pathogens of rhododendron in the United States. A survey was conducted in Greece in October 2009, in which potted plants of Rhododendron spp. were inspected for symptoms of necrotic lesions on leaves and buds caused by P. ramorum. Symptomatic plants were observed in one of the nurseries inspected in the Triphylia Region in southwestern Peloponnese. Isolations from symptomatic leaves on PARBhy-V8 selective agar medium (1) yielded Phytophthora isolates. Colonies on V8 juice agar appeared white and cottony, with a radial growth of 4.2 to 4.6 mm per day at 28°C with a maximum growth temperature of 36°C. Sporangia were produced abundantly on the medium surface and in water; the sporangia were broadly ovoid and papillate and 35 to 50 × 25 to 35 μm. Chlamydospores, 25 to 40 μm in diameter, were observed in 2-week-old cultures, while no sexual structures were observed. Three of the isolates examined were identified as P. nicotianae B. de Haan on the basis of morphological and physiological features (3,4). Genomic DNA was extracted from pure cultures of an isolate and the internal transcribed spacer (ITS) region was amplified using the ITS4/5 primer pair. Sequence analyses by BLAST indicated that the isolates were most similar to P. nicotianae (GenBank Accession No. AJ 854295.1) with sequence identity values of 99%. One of the isolates was deposited in the culture collection of the University of Athens (ATHUM 6519). Detached wounded leaves of Rhododendron hybrid cv. Red Jack were inoculated with agar plugs. Necrotic lesions, similar to those observed in the nursery, appeared on the inoculated leaves after 7 days of incubation at 26°C, while no symptoms developed on control leaves inoculated with sterile agar plugs. The pathogen was consistently reisolated from infected leaves, but not from the controls. P. nicotianae, being a thermophilic species, is the most common Phytophthora species in Greece, reported on more than 30 plant species (2). This pathogen has been reported on Rhododendron spp. in the United States (3,4), but to our knowledge, there was no record of this pathogen on these hosts as yet in Europe and this is the first published report of the pathogen on Rhododendron in Greece. References: (1) A. Belisario et al. Plant Dis. 87:101, 2003. (2) K. Elena. Technical Bulletin No 13. Benaki Phytopathological Institute. Athens, Greece (in Greek), 1999. (3) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996. (4) T. L. Widmer. Online publication. doi: 10.1094/PHP-2010-0317-01-RS, Plant Health Progress, 2010.

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 287-287
Author(s):  
K. S. Han ◽  
J. H. Park ◽  
S. E. Cho ◽  
H. D. Shin

Pachysandra terminalis Siebold & Zucc., known as Japanese pachysandra, is a creeping evergreen perennial belonging to the family Buxaceae. In April 2011, hundreds of plants showing symptoms of leaf blight and stem canker with nearly 100% incidence were found in a private garden in Suwon, Korea. Plants with the same symptoms were found in Seoul in May and Hongcheon in August. Affected leaves contained tan-to-yellow brown blotches. Stem and stolon cankers first appeared as water soaked and developed into necrotic lesions. Sporodochia were solitary, erumpent, circular, 50 to 150 μm in diameter, salmon-colored, pink-orange when wet, and with or without setae. Setae were hyaline, acicular, 60 to 100 μm long, and had a base that was 4 to 6 μm wide. Conidiophores were in a dense fascicle, not branched, hyaline, aseptate or uniseptate, and 8 to 20 × 2 to 3.5 μm. Conidia were long, ellipsoid to cylindric, fusiform, rounded at the apex, subtruncate at the base, straight to slightly bent, guttulate, hyaline, aseptate, 11 to 26 × 2.5 to 4.0 μm. A single-conidial isolate formed cream-colored colonies that turned into salmon-colored colonies on potato dextrose agar (PDA). Morphological and cultural characteristics of the fungus were consistent with previous reports of Pseudonectria pachysandricola B.O. Dodge (1,3,4). Voucher specimens were housed at Korea University (KUS). Two isolates, KACC46110 (ex KUS-F25663) and KACC46111 (ex KUS-F25683), were accessioned in the Korean Agricultural Culture Collection. Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced using ABI Prism 337 automatic DNA sequencer (Applied Biosystems, Foster, CA). The resulting sequence of 487 bp was deposited in GenBank (Accession No. JN797821). This showed 100% similarity with a sequence of P. pachysandricola from the United States (HQ897807). Isolate KACC46110 was used in pathogenicity tests. Inoculum was prepared by harvesting conidia from 2-week-old cultures on PDA. Ten young leaves wounded with needles were sprayed with conidial suspensions (~1 × 106 conidia/ml). Ten young leaves that served as the control were treated with sterile distilled water. Plants were covered with plastic bags to maintain a relative humidity of 100% at 25 ± 2°C for 24 h. Typical symptoms of brown spots appeared on the inoculated leaves 4 days after inoculation and were identical to the ones observed in the field. P. pachysandricola was reisolated from 10 symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in the United States, Britain, Japan, and the Czech Republic (2,3), but not in Korea. To our knowledge, this is the first report of P. pachysandricola on Pachysandra terminalis in Korea. Since this plant is popular and widely planted in Korea, this disease could cause significant damage to nurseries and the landscape. References: (1) B. O. Dodge. Mycologia 36:532, 1944. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , September 24, 2011. (3) I. Safrankova. Plant Prot. Sci. 43:10, 2007. (4) W. A. Sinclair and H. H. Lyon. Disease of Trees and Shrubs. 2nd ed. Cornell University Press, Ithaca, NY, 2005.


Plant Disease ◽  
2006 ◽  
Vol 90 (1) ◽  
pp. 109-109 ◽  
Author(s):  
B. W. Schwingle ◽  
J. A. Smith ◽  
R. A. Blanchette ◽  
S. Gould ◽  
B. L. Blanchette ◽  
...  

Surveys for Phytophthora ramorum in Minnesota nurseries revealed the presence of P. hedraiandra de Cock & Man in't Veld and several other Phytophthora species but not P. ramorum. Symptomatic leaf and stem tissues from diseased Rhododendron and Quercus species were cultured on PARP, a selective growth medium for Phytophthora (3). The Phytophthora isolates obtained were later identified by sequencing the internal transcribed spacer (ITS) region of the rDNA and comparing the sequences with those in GenBank using BLAST searches (1). The ITS sequences of six cultures (GenBank Accession Nos. DQ139804-DQ139809), isolated during 2003 from various Rhododendron cultivars exhibiting leaf lesions and shoot dieback, showed 100% identity with the ITS sequence of P. hedraiandra (GenBank Accession No. AY707987) (2). This is a recently described pathogenic species from the Netherlands responsible for causing leaf spots on Viburnum spp. Since the ITS sequence of P. hedraiandra differs little from that of P. cactorum (2), we verified one isolate to be P. hedraiandra by sequencing the mitochondrial cytochrome c oxidase subunit I gene (cox1) (GenBank Accession No. DQ139810). Comparison of this sequence with the P. hedraiandra voucher specimen in GenBank (Accession No. AY769115) showed 99% identity, which was the closest match. Reproductive structures were measured on V8 juice agar. The average oogonium diameter for three isolates was 29 μm with a range of 26 to 32 μm, while the average antheridium length was 13 μm (11 to 15 μm). Sporangium length and width averages on crushed hemp seeds were 32 μm (28 to 36 μm) and 26 μm (21 to 30 μm), respectively, with the average length to width ratio of 1.25 (1.23 to 1.29). Pathogenicity tests on Rhododendron cv. Mikkeli were carried out using three of our P. hedraiandra isolates. Spore suspensions of 2 × 104 zoospores per ml were used to mist-spray shoots of five, 3-year-old plants for each isolate. Five controls were mist sprayed with water. After inoculation, plants were placed in plastic bags in a dark growth chamber (22°C) for 7 days and then moved to a greenhouse. Leaf blotches and shoot dieback were apparent 5 days after inoculation, and P. hedraiandra was reisolated from those symptomatic tissues and identified by an exact match of the ITS sequence. Necrotic areas lengthened from the shoot tips to the main stems of the plants while expanding into petioles and leaves. No symptoms were observed on control plants. To our knowledge, this is the first report of P. hedraiandra in the United States as well as the first report of Koch's postulates performed with P. hedraiandra on Rhododendron cv. Mikkeli. The significance of this disease to other woody plants in nurseries or the landscape is unknown, and further study is needed to determine the host range and extent of the disease that may occur from this introduction. References: (1) S. F. Altschul et al. J. Mol. Biol. 215:403, 1990. (2) A. W. A.M de Cock and C. A. Lévesque. Stud Mycol 50:481, 2004. (3) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996.


Plant Disease ◽  
2004 ◽  
Vol 88 (4) ◽  
pp. 430-430 ◽  
Author(s):  
D. Hüberli ◽  
K. D. Reuther ◽  
A. Smith ◽  
S. Swain ◽  
J. G. Tse ◽  
...  

In May 2003, Phytophthora ramorum S. Werres & A.W.A.M. de Cock was isolated from leaflets of wood rose (Rosa gymnocarpa Nutt.), a native, low shrub of the Rosaceae family, at the Jack London State Park in Sonoma County, California. Affected leaflets had cream-to-brown lesions or spots, sometimes delimited by a chlorotic zone. Lesions coalesced with time and spread into the petiole and rachis. Lesions on the stems were not observed. Isolates were typical of P. ramorum with large chlamydospores and caduceus, semipapillate sporangia, and the sequence (GenBank Accession No. AY526571) of the internal transcribed spacer (ITS) region of the rDNA matched those published previously (4). The site was a mixed forest containing some confirmed P. ramorum-infected trees of coast redwood (Sequoia sempervirens), bay laurel (Umbellularia californica), and tanoak (Lithocarpus densiflorus) (3,4). These sites also contained California rose (R. californica Cham. & Schldl.); however, no symptoms were observed on this species. A terminal leaflet of asymptomatic, pesticide-free, potted-plants of California rose and wood rose (four plants each) was inoculated with zoospores of a P. ramorum isolate (American Type Culture Collection, Manassas, VA, ATCC MYA-3281; Centraal Bureau voor Schimmelcultures, Baarn, the Netherlands, CBS 114390) obtained from infected wood rose (2). A control leaflet of each plant was dipped in sterile deionized water. Branches containing the inoculated and control leaflets were placed in moist plastic bags, and plants were maintained at 21 to 22°C in the laboratory for 6 days. The inoculation experiment was repeated. In both inoculations, brown lesions (extending up to 8 mm from the leaflet tip) were observed on leaflets of both species 2 days after inoculation with P. ramorum. At 6 days after inoculation, lesions starting from the leaflet tip averaged 12.2 mm in length (range 10 to 16 mm) for wood rose and 9.6 mm (range 3 to 20 mm) for California rose. Some lesions extended into the petiole in both rose species. Sporangia were observed in washings of the lesions from four plants of California rose and one plant of wood rose, and P. ramorum was reisolated on Phytophthora-selective agar medium modified with 25 mg of pentachloronitrobenzene (PCNB) (4) from all lesions. Control leaflets had no lesions, and P. ramorum was not reisolated. To our knowledge, this is the first report of a species of Rosa as a natural host for P. ramorum, although R. sempervirens was identified as being susceptible in artificial inoculations of detached leaves (E. Moralejo and L. Hernández, personal communication). Toyon (Heteromeles arbutifolia) in California and salmon berry (Rubus spectabilis) in Oregon are the other known hosts from the family Rosaceae (1). Wood rose is popular in the horticultural industry and is readily available from native plant nurseries in California, Oregon, Washington, and British Columbia, Canada. California rose is also popular, primarily in California. The pathogen could be disseminated on these plants, especially since sporangia were obtained from inoculated leaflets of these two species. References: (1) J. M. Davidson et al. On-line publication. doi:10.1094/PHP-2003-0707-01-DG. Plant Health Progress, 2003. (2) D. Hüberli et al. Plant Dis. 87:599, 2003. (3) P. E. Maloney et al. Plant Dis. 86:1274, 2002. (4) D. M. Rizzo et al. Plant Dis. 86:205, 2002.


Plant Disease ◽  
2003 ◽  
Vol 87 (10) ◽  
pp. 1266-1266 ◽  
Author(s):  
Sabine Werres ◽  
Daphné De Merlier

Since its original isolation in 1993, Phytophthora ramorum has become an important pathogen. Initially, it was determined to be the causal agent of a twig blight of Rhododendron spp. in Germany and the Netherlands (3). Around the same period, symptoms and mortality on oak (Quercus spp.) and tanoak (Lithocarpus densiflorus) were associated with P. ramorum in California (2), where the disease was named sudden oak death. Subsequently, P. ramorum has been detected on a wide range of forest trees and shrub species in the United States. In Europe, the pathogen has spread to many countries, primarily on nursery plants of Rhododendron and Viburnum spp., and recently, on Camellia japonica, Kalmia latifolia, Pieris formosa var. forrestii, P. japonica, Leucothoe sp., Syringa vulgaris, and Taxus baccata. P. ramorum has not been observed in European forests. P. ramorum is heterothallic, and initial in vitro mating studies on agar media suggested that only the A1 mating type occurred in Europe, while only the A2 mating type was present in the United States (4). However, an isolate collected in 2002 in Belgium (1) appears to be the A2 mating type. This isolate (CBS 110901, Centraal Bureau voor Schimmelcultures, Baarn, the Netherlands) originated from an imported V. bodnantense plant at an ornamental nursery. A hyphal tip culture (BBA 26/02) of this isolate produced no oogonia on carrot piece agar after 6 weeks in pairing tests with other Phytophthora species of mating type A2. When paired with mating type A1 of P. cambivora, P. cinnamomi, P. cryptogea, and P. drechsleri, however, oogonia were observed in all pairings within 6 weeks. The number of oogonia was low in all pairings but was highest in pairings with P. cryptogea. No oospores were produced after 6 weeks between P. ramorum isolates BBA 26/02 and BBA 9/95 (from the holotype, mating type A1), but gametangia were observed when these isolates were paired on Rhododendron sp. twigs. Normal oogonia were produced on the outgrowing mycelium when pieces from these twigs were placed on carrot piece agar. The shape and size of the oogonia produced on carrot piece agar after pairing with P. cryptogea and on Rhododendron sp. twigs after pairing with P. ramorum BBA 9/95 were similar (24 to 34 μm, mean 29.6 μm and 25 to 33 μm, mean 30.6 μm, respectively). To our knowledge, this is the first observation of P. ramorum mating type A2 in Europe. References: (1) D. De Merlier et al. Plant Dis. 87:203, 2003. (2) D. M. Rizzo et al. Plant Dis. 86:205, 2002. (3) S. Werres et al. Mycol. Res. 105:1166, 2001. (4) S. Werres and B. Zielke. J. Plant Dis. Prot. 110:129, 2003.


Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1353-1353 ◽  
Author(s):  
A. Garibaldi ◽  
D. Bertetti ◽  
P. Pensa ◽  
M. L. Gullino

Petunia × hybrida (Solanaceae) includes several hybrids that are grown as ornamental plants and are very much appreciated for their long-lasting flowering period. During the spring of 2009, extensive wilting was observed on 2-month-old potted plants of Petunia × hybrida cv. Sanguna Lilac Vein grown in a commercial glasshouse near Albenga (northern Italy). First symptoms included stem necrosis and darkening and withering of leaves. Wilt occurred a few days after the appearance of the first symptoms. Infected plants were characterized by the presence of soft, watery tissues. In the presence of high relative humidity, lesions became covered with a whitish mycelium and irregular, dark gray sclerotia (3.0 to 6.5 × 2.0 to 5.0 mm, average 4.8 × 3.3 mm) were produced on the mycelium. Diseased tissue was surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/l of streptomycin sulfate. Sclerotinia sclerotiorum (Lib.) de Bary (3) was consistently recovered from infected stem pieces. Sclerotia produced on PDA measured 2.0 to 6.0 × 1.5 to 5.0 mm (average 3.9 × 3.1) mm. The internal transcribed spacer (ITS) region of rDNA was amplified with primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 548-bp segment showed a 100% homology with the sequence of S. sclerotiorum. The nucleotide sequence has been assigned GenBank Accession No. GQ375746. Pathogenicity of one isolate obtained from sclerotia of infected plants was confirmed by inoculating three 90-day-old plants belonging to cv. Sanguna Lilac Vein transplanted in 22-cm-diameter pots in a glasshouse in a sphagnum peat/pomix/pine bark/clay (50:20:20:10) mix. Inoculum that consisted of 2 g/liter of substrate of wheat kernels infested with mycelium and sclerotia was placed in the soil and around the base of each plant. Three noninoculated plants served as controls. Plants were maintained in greenhouse at temperatures ranging between 22 and 26°C and relative humidity >90%. The inoculation trial was carried out twice. All inoculated plants developed leaf yellowing by 20 days after soil infestation. White, cottony mycelium and dark sclerotia developed on stems and at the base of all inoculated plants. Eventually, infected plants wilted. Control plants remained symptomless. S. sclerotiorum was reisolated from the stems of inoculated plants. To our knowledge, this is the first report of S. sclerotiorum on Petunia × hybrida in Italy. The disease has been previously reported on Petunia × hybrida in Bermuda (2) and the United States (4). References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) R. M. Brien. N.Z. J. Sci. Tech., A, 24, 62, 1942. (3) N. F. Buchwald. Kongl. Veterisk Landb. Aarssk. 75, 1949. (4) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989.


Plant Disease ◽  
2013 ◽  
Vol 97 (11) ◽  
pp. 1510-1510 ◽  
Author(s):  
J. H. Park ◽  
K. S. Han ◽  
J. Y. Kim ◽  
H. D. Shin

Sansevieria, Sansevieria trifasciata Prain, is cultivated in greenhouses and is used as a potted interior foliage plant in Korea. In April 2012, several plants (cv. Moonshine) exhibiting typical anthracnose symptoms from a local nursery were sent to the plant clinic of Gyeonggi-Do Agricultural Research and Extension Services for diagnosis. The leaf lesions began as round, partly water-soaked, pale greenish to grayish spots, which enlarged and ultimately coalesced, resulting in severe leaf blight. Concentric rings of blackish acervuli were formed in the expanding lesions of mostly 2 to 4 cm in diameter. Acervuli were mostly epiphyllous, circular to ellipsoid. Setae were aseptate to 3-septate, dark brown at the base, paler upwards, acicular, and up to 180 μm long. Conidia (n = 30) were oblong-elliptical to obovate, sometimes fusiform-elliptical, guttulate, hyaline, and 14 to 24 × 5 to 7.5 μm (mean 18.6 × 6.4 μm). Hyphopodial appressoria were dark brown to blackish, globose to clavate in outline, and 5 to 12 × 4 to 8 μm. Colonies on potato dextrose agar (PDA) were grayish-white, felted with cottony-white aerial mycelium on a gray to olivaceous gray background in culture. Gelatinous salmon- to orange-colored conidial masses were produced abundantly after one week's incubation. The morphological and cultural characteristics of the fungus were consistent with the description of Colletotrichum sansevieriae M. Nakamura & M. Ohzono (2,3). A voucher specimen was deposited in the Korea University herbarium (KUS-F26637). An isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC46835). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting 569-bp sequences were deposited in GenBank (Accession No. KC847065). A BLAST search in GenBank exhibited 100% nucleotide identity with sequence of C. sansevieriae (JF911349) from the United States and >99% similarity with that of HQ433226 from Australia. To confirm pathogenicity, inoculum was prepared by harvesting conidia from 3-week-old cultures on PDA. A conidial suspension (2 × 106 conidia/ml) was sprayed over the five leaves of sansevieria ‘Moonshine’ wounded with a fine needle. Five leaves sprayed with sterile water served as controls. Plants were covered with plastic bags to maintain 100% relative humidity for 48 h and then kept in a greenhouse (22 to 28°C and 70 to 80% RH). Within 12 days, symptoms identical to those observed in originally infected leaf developed on all inoculated leaves. No symptoms were observed on control plants. C. sansevieriae was reisolated from the lesions of inoculated plants, fulfilling Koch's postulates. Sansevieria anthracnose associated with C. sansevieriae has been reported in Japan (2), Australia (1), and the United States (3). To our knowledge, this is the first report of sansevieria anthracnose in Korea. Our observations in sansevieria nurseries suggest that preventing wound infection as well as maintaining good plant hygiene in greenhouses might be main strategies for this disease. References: (1) R. Aldaoud et al. Australas. Plant Dis. Notes 6:60, 2011. (2) M. Nakamura et al. J. Gen. Plant Pathol. 72:253, 2006. (3) A. J. Palmateer et al. Plant Dis. 96:293, 2012.


2019 ◽  
Vol 94 (2) ◽  
pp. 273-278
Author(s):  
Björn Kröger ◽  
Juan Carlos Gutiérrez-Marco

AbstractThe order Intejocerida is an enigmatic, short-lived cephalopod taxon known previously only from Early–Middle Ordovician beds of Siberia and the United States. Here we report a new genus, Cabaneroceras, and a new species, C. aznari, from Middle Ordovician strata of central Spain. This finding widens the paleogeographic range of the order toward high-paleolatitudinal areas of peri-Gondwana. A curved conch, characteristic for the new genus, was previously unknown from members of the Intejocerida.UUID: http://zoobank.org/21f0a09c-5265-4d29-824b-6b105d36b791


2016 ◽  
Vol 148 (5) ◽  
pp. 616-618 ◽  
Author(s):  
E.R. Echegaray ◽  
R.N. Stougaard ◽  
B. Bohannon

AbstractEuxestonotus error (Fitch) (Hymenoptera: Platygastridae) is considered part of the natural enemy complex of the wheat midge Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae). Although previously reported in the United States of America, there is no record for this species outside the state of New York since 1865. A survey conducted in the summer of 2015 revealed that E. error is present in northwestern Montana and is likely playing a role in the suppression of wheat midge populations.


Plant Disease ◽  
2002 ◽  
Vol 86 (1) ◽  
pp. 71-71
Author(s):  
A. Garibaldi ◽  
A. Minuto ◽  
M. L. Gullino

The production of potted ornamental plants is very important in the Albenga Region of northern Italy, where plants are grown for export to central and northern Europe. During fall 2000 and spring 2001, sudden wilt of tussock bellflower (Campanula carpatica Jacq.) and butterfly flower (Schizanthus × wisetonensis Hort.) was observed on potted plants in a commercial greenhouse. Initial symptoms included stem necrosis at the soil line and yellowing and tan discoloration of the lower leaves. As stem necrosis progressed, infected plants growing in a peat, bark compost, and clay mixture (70-20-10) wilted and died. Necrotic tissues were covered with whitish mycelia that produced dark, spherical (2 to 6 mm diameter) sclerotia. Sclerotinia sclerotiorum was consistently recovered from symptomatic stem pieces of both plants disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar amended with streptomycin sulphate at 100 ppm. Pathogenicity of three isolates obtained from each crop was confirmed by inoculating 45- to 60-day-old C. carpatica and Schizanthus × wisetonensis plants grown in containers (14 cm diameter). Inoculum that consisted of wheat kernels infested with mycelia and sclerotia of each isolate was placed on the soil surface around the base of previously artificially wounded or nonwounded plants. Noninoculated plants served as controls. All plants were maintained outdoors where temperatures ranged between 8 and 15°C. Inoculated plants developed symptoms of leaf yellowing, followed by wilt, within 7 to 10 days, while control plants remained symptomless. White mycelia and sclerotia developed on infected tissues and S. sclerotiorum was reisolated from inoculated plants. To our knowledge, this is the first report of stem blight of C. carpatica and Schizanthus × wisetonensis caused by S. sclerotiorum in Italy. The disease was previously observed on C. carpatica in Great Britain (2) and on Schizanthus sp. in the United States (1). References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989. (2) J. Rees. Welsh J. Agric. 1:188, 1925.


2019 ◽  
Vol 7 ◽  
Author(s):  
Rammohan Balusu ◽  
Elijah Talamas ◽  
Ted Cottrell ◽  
Michael Toews ◽  
Brett Blaauw ◽  
...  

A parasitoid wasp, Trissolcus basalis (Wollaston), was recorded parasitizing eggs of the invasive stink bug Halyomorpha halys (Stål) in the United States. This is the first record of this species parasitizing fresh and frozen eggs of H. halys in the United States. First record of Trissolcus basalis parasitizing Halyomorpha halys eggs in the United States.


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