First Report of Cylindrocarpon sp. Associated with Root Rot Disease of Strawberry in North Carolina.

Strawberry (Fragaria × ananassa Duchesne) is an economically important fruit crop in North Carolina for domestic consumption and export. In April 2012, outbreaks of a destructive root disease were observed in strawberry cv. Chandler in Buncombe, New Hanover, and Roman counties, North Carolina. Samples from Rowan (ID 13175) and Buncombe (ID 13193) counties submitted to the Plant Disease and Insect Clinic of the Department of Plant Pathology, North Carolina State University, exhibited yellowing and wilting of leaves and extensive root necrosis, and disease severity based on field symptoms ranged from 20 to 30%. To identify the pathogen, five small pieces of necrotic crown and root tissues were taken from each sample, surface disinfested for 1 min in a 1.5% sodium hypochlorite solution, and plated onto potato dextrose agar (PDA) with 0.5 g liter-1 of streptomycin sulfate. Colonies developing from the tissue samples were transferred to PDA. Colonies from both samples were identical, grew relatively slowly, and gradually turned yellowish to partially brownish. After about 7 days, abundant conidia were formed. These were hyaline, mostly straight with both ends rounded, predominantly three septate, and 40 to 50 × 5 to 10 µm. Based on morphological characteristics, these isolates were identified as a species of Cylindrocarpon (1) To confirm the original identification of the fungus as a species of Cylindrocarpon, genomic DNA of both isolates was extracted from mycelia using DNeasy Plant Mini Kit (Qiagen Inc., Valencia, CA) and analyzed using PCR (2). The internal transcribed spacers (ITS)1 and (ITS)2 flanking the 5.8S rRNA regions were amplified and sequenced using universal primers ITS1 (forward) and ITS4 (reverse). The sequences of the 421 bp (GenBank KC847090 and KC847091) of both isolates were identical. Furthermore, a BLASTn search of these sequences showed homology of 99% with the sequences of Cylidrocarpon species (AB369421.1, AM419069.1, AM419074.1, AY295332.1, JN031017.1, JN253505.1, and JQ886422.1), To fulfill Koch's postulates, inoculum of each isolate was prepared and adjusted to 1.5 × 107 conidia/ml using a hemacytometer. 'Chandler' strawberry plants were grown in 25-cm diameter plastic pots (one seedling per pot) in the greenhouse and five 6-week-old plants were injected with conidia of each isolate into the base of crown using a 5-ml syringe. The plants were covered with clear plastic for 24 h and left on the greenhouse bench with a 16-h photoperiod and 25/20°C day/night temperatures and assessed for disease development 14 days after inoculation. The inoculated plants exhibited wilting and root necrosis, consistent with the symptoms observed on strawberry plants in the field. Control plants treated with distilled water remained healthy. Isolations were made from the inoculated plants and the fungus used for inoculation was recovered from all plants. The morphology of these isolates was in agreement with published descriptions of Cylindrocarpon (1). To our knowledge, this is the first report of a Cylindrocarpon sp. causing crown and root rot on strawberry in North Carolina and effective disease management strategies need to be explored. References: (1) C. D. Booth. Mycol. Pap. (CMI) 104:1, 1996. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

Fungal Planet description sheets: 154-213.

Novel species of microfungi described in the present study include the following from South Africa: Camarosporium aloes, Phaeococcomyces aloes and Phoma aloes from Aloe, C. psoraleae, Diaporthe psoraleae and D. psoraleae-pinnatae from Psoralea, Colletotrichum euphorbiae from Euphorbia, Coniothyrium prosopidis and Peyronellaea prosopidis from Prosopis, Diaporthe cassines from Cassine, D. diospyricola from Diospyros, Diaporthe maytenicola from Maytenus, Harknessia proteae from Protea, Neofusicoccum ursorum and N. cryptoaustrale from Eucalyptus, Ochrocladosporium adansoniae from Adansonia, Pilidium pseudoconcavum from Greyia radlkoferi, Stagonospora pseudopaludosa from Phragmites and Toxicocladosporium ficiniae from Ficinia. Several species were also described from Thailand, namely: Chaetopsina pini and C. pinicola from Pinus spp., Myrmecridium thailandicum from reed litter, Passalora pseudotithoniae from Tithonia, Pallidocercospora ventilago from Ventilago, Pyricularia bothriochloae from Bothriochloa and Sphaerulina rhododendricola from Rhododendron. Novelties from Spain include Cladophialophora multiseptata, Knufia tsunedae and Pleuroascus rectipilus from soil and Cyphellophora catalaunica from river sediments. Species from the USA include Bipolaris drechsleri from Microstegium, Calonectria blephiliae from Blephilia, Kellermania macrospora (epitype) and K. pseudoyuccigena from Yucca. Three new species are described from Mexico, namely Neophaeosphaeria agaves and K. agaves from Agave and Phytophthora ipomoeae from Ipomoea. Other African species include Calonectria mossambicensis from Eucalyptus (Mozambique), Harzia cameroonensis from an unknown creeper (Cameroon), Mastigosporella anisophylleae from Anisophyllea (Zambia) and Teratosphaeria terminaliae from Terminalia (Zimbabwe). Species from Europe include Auxarthron longisporum from forest soil (Portugal), Discosia pseudoartocreas from Tilia (Austria), Paraconiothyrium polonense and P. lycopodinum from Lycopodium (Poland) and Stachybotrys oleronensis from Iris (France). Two species of Chrysosporium are described from Antarctica, namely C. magnasporum and C. oceanitesii. Finally, Licea xanthospora is described from Australia, Hypochnicium huinayensis from Chile and Custingophora blanchettei from Uruguay. Novel genera of Ascomycetes include Neomycosphaerella from Pseudopentameris macrantha (South Africa), and Paramycosphaerella from Brachystegia sp. (Zimbabwe). Novel hyphomycete genera include Pseudocatenomycopsis from Rothmannia (Zambia), Neopseudocercospora from Terminalia (Zambia) and Neodeightoniella from Phragmites (South Africa), while Dimorphiopsis from Brachystegia (Zambia) represents a novel coelomycetous genus. Furthermore, Alanphillipsia is introduced as a new genus in the Botryosphaeriaceae with four species, A. aloes, A. aloeigena and A. aloetica from Aloe spp. and A. euphorbiae from Euphorbia sp. (South Africa). A new combination is also proposed for Brachysporium torulosum (Deightoniella black tip of banana) as Corynespora torulosa. Morphological and culture characteristics along with ITS DNA barcodes are provided for all taxa.

Measuring forces with the AFM: polymeric surfaces in liquids.

This review links together for the first time both the practicalities of force measurement and the work carried out to date on force detection between polymeric surfaces in liquids using the atomic force microscope (AFM). Also included is some of the recent work that has been carried out between surfactant surfaces and biologically coated surfaces with the AFM. The emphasis in this review is on the practical issues involved with force measurement between these types of surfaces, and the similarities and irregularities between the observed types of forces measured. Comparison is made between AFM and surface force apparatus (SFA) measurements, as there is a much longer history of work with the latter. Results indicate that forces between the surfaces reviewed here are a complicated mixture of steric-type repulsion, conformational behaviour on separation and long-range attraction, which is often ascribed to 'hydrophobic' forces. The origin of this latter force remains uncertain, despite its almost ubiquitous appearance in force measurements with these types of surfaces.

Etiology of apple sooty blotch disease in north Carolina.

ABSTRACT Sooty blotch disease of apples (Malus x domestica), previously attributed to the fungus Gloeodes pomigena, was shown to be a disease complex caused by fungi previously considered mycelial types of G. pomigena. Peltaster fructicola and Geastrumia polystigmatis were associated with the ramose mycelial type. A fungus similar to P. fructicola, but with smaller pycnothyria and conidia, was associated with the punctate mycelial type. The diffuse fuliginous mycelial type was caused by Leptodontium elatius. Fungi that fit the classical morphological description of G. pomigena were not observed. Pycnothyria of P. fructicola developed on overwintered colonies on blackberries, and conidia were a source for primary infection during the entire growing season. Secondary spread was through conidia produced in colonies on fruit. L. elatius was observed infrequently producing conidia on fruit during periods of extended high moisture. Histological examination did not reveal penetration of the cuticle of apple fruit for any of the fungi of the apple sooty blotch complex.

Re-examination of Peltaster fructicola, a member of the apple sooty blotch complex.

Peltaster fructicola is one of several fungi that causes sooty blotch on apple. Johnson et al (1996, 1997) correctly described P. fructicola but illustrated two different fungi. One is P. fructicola and the other is an unidentified ascomycete. In this paper, P. fructicola is more completely described and accurately illustrated.

First Report of Stigmina lautii in the United States.

In June 1999, a specimen of blue spruce (Picea pungens) from Avery County, North Carolina, exhibiting symptoms of needle blight was submitted to the Plant Disease and Insect Clinic at North Carolina State University. A fungus sporulating profusely on symptomatic needles was identified as Stigmina lautii. Since then, three additional specimens have been received-on blue spruce from Ashe County, on Norway spruce (P. abies) from Avery County, and on Picea sp. from Cherokee County. These counties are all in western North Carolina but are not contiguous, indicating that the fungus is probably widespread in the western part of the state. S. lautii was described by Sutton (2) in 1973 on black spruce (P. mariana) and white spruce (P. glauca) collected from various locations in Manitoba and Saskatchewan, Canada. The only other reference found to the fungus is a specimen collected in British Columbia, Canada, on P. glauca in 1972 (2). The morphology of the North Carolina specimens of S. lautii is essentially as described by Sutton. The dark brown, superficial, flattened sporodochia are developed only through stomata. Sporodochia are found both on symptomatic needles as well as on adjacent green needles. Conidiophores arise only laterally from the lower, outer cells of the sporodochium, and are macronematous, mononematous, brown, smooth, unbranched, 1 to 2 septate, and 10 to 20 × 4 to 6 µm. Conidiogenous cells are brown, monoblastic, integrated, terminal, percurrent with 3 to 4 annelations, and 6 to 12 × 4 to 5 µm. Conidia are pale brown, cylindrical to fusiform, often curved, thick walled, verrucose, 5 to 8 distoseptate, and 25 to 45 × 5 to 6 µm. Superficially, the sporodochia of S. lautii might be confused with pycnidia of Rhizosphaera kalkhoffii, which also arise through stomata. The latter fungus also is associated with a needle blight of Picea spp. in western North Carolina. Both fungi were present on one specimen examined. Currently, no information is available on the pathogenicity of S. lautii, but its association with typical needle blight symptoms and the known pathogenicity of other Stigmina spp. on conifers make it likely that the fungus is pathogenic to spruce. To my knowledge, this is the first report of S. lautii in the United States, and P. pungens and P. abies represent new host records for the fungus. Specimens BPI 747910 and 840959, have been deposited in the herbarium of the National Fungus Collections, Beltsville, MD. References: (1) J. H. Ginns. Page 158 in: Compendium of Plant Disease and Decay Fungi in Canada 1960-1980. Agric. Can. Publ. 1813, 1986. (2) B. C. Sutton. Mycol. Pap. 132:113, 1973.

First Report of Thyronectria austroamericana Canker on Thornless Honey Locust in North Carolina.

Specimens from a thornless honey locust (Gleditsia triacanthos var. inermis 'Shade Master') with cankers were submitted in May 1999 to the North Carolina State University Plant Disease and Insect Clinic by staff from the North Carolina Zoological Park (Asheboro). Abundant stromata of Gyrostroma austroamericana, the anamorph of Thyronectria austroamericana, were associated with the cankers. A visit to the Zoological Park during August 1999 revealed seven additional honey locust trees with multiple branch and stem cankers and dieback. All infected trees had perithecia of T. austroamericana and/or its anamorph. The fungus is distinguished by the large clusters of yellow-brown perithecia with dark brown tips produced on stromata emerging from lenticels, elliptical muriform ascospores, and sparse ascoconidia (1,2). Ascoconidia form as the result of ascospores budding within the ascus. Other trees of the cultivar are an integral part of the landscaping theme of the African Pavilion of the park, and park staff were concerned about disease spread. Infected trees were 8 years old, and several had evidence of sunscald cankers, a common infection court of T. austroamericana (2). Thornless cultivars of honey locust are popular landscape plants in the central and eastern United States and may be seriously affected by T. austroamericana (2). Apparently 'Shade Master' is very susceptible to the fungus and should not be used as a landscape tree, especially where the disease has been reported. This is the first report of T. austroamericana in North Carolina on any host. Voucher specimens have been deposited in the National Fungus Collection, Beltsville, MD (BPI 74693), and in the Mycological Herbarium, Department of Plant Pathology, North Carolina State University, Raleigh. References: (1) E. V. Seeler, Jr. J. Arnold Arbor. Harv. Univ. 21:429, 1940. (2) W. A. Sinclair et al. 1993. Diseases of Trees and Shrubs. Cornell University Press, Ithaca, NY.