High Humidity Chamber Research Articles

Hypobaric Storage of Representative Root, Leaf, Fruit, and Flower Tissues: Comparisons to Storage at Atmospheric Pressure and Normoxia

Hypobaric or low-pressure storage (LPS) is a technology that has been reported to have significant potential to preserve fresh produce quality. However, excessive moisture loss has often been erroneously reported to limit the utility of LPS. We report on hypobaric (1.6 to 2.0 kPa) storage of representative bulky and leafy fruits and vegetables {strawberry (Fragaria ×ananassa Duchesne ex Rozier) fruit, carrot [Daucus carota subsp. sativus (Hoffm.) Arcang.] roots, spinach (Spinacia oleracea L.) leaves, and rose (Rosa ×hybrida ‘Attaché Pink’) flowers} using a laboratory-scale LPS and provide data on the regulation of humidity and temperature and describe effects on moisture loss and quality. The LPS achieved near saturation (>99.5%) of water without condensation on the chamber sidewalls. This required tight regulation of the chamber wall temperature (2.2 °C ± 0.15 °C) and careful control of the flux of air into the chamber. The rate of moisture loss was unaffected by the pressure of the storage atmosphere; however, it was affected by commodity, being lower for strawberry than for carrot or spinach, and averaging 0.08%, 0.40%, and 0.35% per day, respectively (average of normal and low pressure combined). Moisture loss of long-stemmed rose in LPS averaged 0.071% per day over an 8-week storage period. Although moisture loss was low, the LPS environment appeared to enhance water loss from deeper within plant tissues than storage at atmospheric pressure and, in roses, resulted in bent neck 2 or 3 days after removal from storage after 3 weeks. For this reason, LPS did not benefit storability of cut ‘Attaché Pink’ roses compared with high-humidity chambers maintained at atmospheric pressure.

First report of Seimatosporium vitifusiforme causing trunk disease in Chilean grapevines (Vitis vinifera).

Grapevine is one of the most important fruit crops in Chile and trunk diseases reduce the productivity, quality, and longevity of the vineyards. A survey was conducted in ancient (> 50 years) vineyards of Cauquenes (35°57´14´´S 72°17´07´´W) and Itata valleys (36°38´13´´S 72°30´57´´W), located in the central area of Chile, during 2019. Trunks and cordons showing dieback and dark brown to black wood discoloration were collected from 50 to 200-year-old plants of six cultivars: País, Moscatel, Torontel Amarilla, Carignan, Aliatica and Aligote. The bark was removed and 0.5-cm sections were cut from the edges of necrotic wood lesions. Subsequently, pieces were surface disinfected using 10% v/v sodium hypochlorite bleach (4.9% chlorine), plated on acidified quarter-strength potato dextrose agar (APDA) (25% PDA, acidified with 0.1% v/v 85% lactic acid) and incubated at 25°C, for 14 to 28 days. Hyphal tips were excised and transferred to PDA to obtain pure cultures. Along with the conidiomata and conidia produced, growth rate, color and shape of the colonies on PDA, after 7 and 14 days of incubation at 25°C (n=17), were recorded. DNA was extracted from pure cultures of three isolates on PDA: HMV3, HMV64 and HMV81. The internal transcribed spacer region and partial β-tubulin genes were amplified, using ITS1/ITS4 (White et al. 1990) and bt2A/bt2B (Glass & Donaldson 1995) primers, respectively. Sequences were subjected to NCBI BLAST search and compared to the published sequences. Isolated colonies were whitish to light-brown, cottony with a smooth margin (n=37). Their mycelium grew 1.9 cm after 7-days and 3.2 cm after 14-days of incubation on PDA, at 25°C. Colonies produced black globose pycnidia and curved, slightly-pigmentated, three-septated conidia 22.3-(29.8)-32.2 x 3.9-(4.8)-5.3 µm (n=30), with apical and basal flexuous appendages 4.3-(12.7)-21.5 µm (n=20). When compared to type sequences of Seimatosporium vitifusiforme (Lawrence et al. 2018), ITS and βtub sequences identity of these isolates were 99 to 100% identical. To produce uniform healthy plants for pathogenicity tests, Petit Syrah canes (1-year old) were rooted in tap water amended with 500 ppm of indole-butyric acid, for 30 days. Plants were inoculated with 0.5-cm diameter mycelial plugs of actively growing colonies of the isolates HMV3, HMV64 and HMV81 (GenBank accessions no. MW026664, MW048518; MW026665, MW048519, and MW026666, MW048520, respectively). Sterile agar plugs were used for controls. Five plants per pathogen isolate were incubated at 25°C, in a humid chamber, for 25 days, and seven additional plants per isolate were incubated in aerated tap water, for 55 days. After the incubation period, the bark was removed and the lesions were measured. Dark necrotic lesions identical to the original observations were reproduced, both in the high humidity chamber (6% length) and water (10% length). There were no differences in lesion length among the isolates (P < 0.05). Control vines remained asymptomatic. To fulfill Koch´s postulates, isolations were made from symptomatic vines and compared to the ones used for inoculation, and found to be identical. Seimatosporium vitifusiforme was previously reported as a pathogen of Vitis vinifera in California, USA (Lawrence et al. 2018). Consequently, this is the second report of this fungus as a grapevine pathogen and the first one affecting Latin-American grapevines.

Characterization of the Alteration of Debitus Grisailles

ABSTRACT Stained glass restoration generally involves filling glass losses to maintain the coherence of the window and the new glasses used to fill the losses can be painted to chromatically reintegrate the stained glass panel. One of the most common painting materials on stained glass is grisaille, a paint made by mixing metal oxides with a ground lead glass. Grisailles usually have black and brown hues and are used for the creation of outlines as shadows in window glasses. Although several commercial companies sell many types of products to paint on glass, few of them present the necessary compatibility with the original materials that conservation materials must have. Debitus is one of the most renowned companies, and its grisailles are frequently used for chromatic reintegration in stained glass window restoration. Thus, the main objective of this study was to assess the long-term stability and durability of commercial Debitus grisailles. Two alteration tests were carried out, with samples placed in high humidity chambers and submerged in distilled water. The samples and degradation products were characterized by optical microscopy, µ-Raman spectroscopy, and colourimetry. In the immersion, the pH of the water was measured during the experiment, and the leached elements were analyzed at the end by inductively coupled plasma atomic emission spectroscopy. The results showed an alteration of the colour and the formation of degradation products, identified as sulphates. The solution pH was increased by the aqueous extraction of alkaline and alkaline-earth ions from the support glass of the samples. Despite these changes, it was possible to conclude that these commercial grisailles presented good durability and stability for use in conservation treatments.

Brown spot in table grape Redglobe controlled in study with sulfur dioxide and temperature treatments

Brown spot is a postharvest disease of grapes caused byCladosporiumspecies in the San Joaquin Valley of California. It spreads during cold storage and transport, resulting in severe economic losses to late table grape cultivars, which are grown mainly for export to countries such as China and Mexico. We examined the effect of temperature and sulfur dioxide (SO2) treatments on fungal growth and infection of Redglobe berries by threeCladosporiumspecies:Cladosporium ramotenellum, C. cladosporioidesandC. limoniforme.Redglobe is especially popular for export. Fungal colonies growing on potato dextrose agar in petri plates stored at −2°C grew slower than those stored at 2°C, and an 400 ppm-h SO2treatment significantly reduced fungal growth of all three species and at all temperatures tested. Redglobe berries inoculated with theCladosporiumspecies, treated with SO2concentrations of 100 ppm-h, 200 ppm-h and 400 ppm-h and incubated in high relative humidity chambers for 28 to 32 days at 2°C, showed little incidence of disease. The development of brown spot on berries was entirely prevented with the treatment of 200 ppm-h SO2for allCladosporiumspecies tested.

Morphology of cementitious material during early hydration

Morphology of hydration products, mainly calcium-silicate-hydrate (C-S-H), has a strong influence on the mechanical and transport properties of hardened cementitious materials. This paper examines the effect of curing conditions and drying methods during specimen preparation on C-S-H morphology. It shows that an appropriate drying method, either supercritical drying (SCD) or isopropanol (IPA) replacement, is able to preserve the delicate microstructure on both macro and micro scales. On the surface of the specimen, the structure is fibrillar for specimens cured in high relative humidity (RH) chamber or reticular for specimens cured in pore solution/limewater. A thin layer with cluster-like structure was found for specimens cured in high RH. By observing the fracture surface, it is found that the interior morphology is complex and varies with depth and curing methods. Consequently, one must take into account the effect of ion transport during the curing and drying when preparing specimens for microstructure analysis. We proposed that the basic units of C-S-H are fine fibers and thin sheets.

Effect of fine crack width and water cement ratio of SHCC on chloride ingress and rebar corrosion

SHCC (Strain Hardening Cement-based Composite) is a material known for its strain-hardening behavior under tensile and bending stress and its characteristic numerous small cracks. SHCC is expected to show superior durability because of the fineness of the cracks. In this study, chloride ingress through cracks into SHCC and progress of rebar corrosion in three mixtures of SHCC with various water-cement ratios were investigated. Through a chloride solution immersion test, it was confirmed that chloride could penetrate through even very fine cracks. The resistivity of cracked SHCC against chloride ingress is mainly governed by the accumulated crack width and the water cement ratio. Chloride pre-mixed SHCC specimens were left in a high-temperature, high-humidity chamber for 11 months to promote rebar corrosion. While the accumulated crack width and the water cement ratio were both influential to an increase in corrosion area, only the water cement ratio had bearing on corrosion loss.

First Report of Botrytis Blight Caused byBotrytis cinereaonCalendula officinalisin Italy

HomePlant DiseaseVol. 101, No. 1First Report of Botrytis Blight Caused by Botrytis cinerea on Calendula officinalis in Italy PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Botrytis Blight Caused by Botrytis cinerea on Calendula officinalis in ItalyA. Garibaldi, D. Bertetti, P. Pensa, S. Franco Ortega, and M. L. GullinoA. GaribaldiSearch for more papers by this author, D. BertettiSearch for more papers by this author, P. PensaSearch for more papers by this author, S. Franco OrtegaSearch for more papers by this author, and M. L. GullinoSearch for more papers by this authorAffiliationsAuthors and Affiliations A. Garibaldi D. Bertetti P. Pensa S. Franco Ortega M. L. Gullino , Centre of Competence for the Innovation in the Agro-Environmental Sector (AGROINNOVA), 10095 Grugliasco, Italy. Published Online:24 Oct 2016https://doi.org/10.1094/PDIS-07-16-1016-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Calendula officinalis (pot marigold) is an annual herbaceous plant belonging to the Asteraceae family, appreciated for the abundant production of gaudy inflorescences. In Liguria region (northern Italy), this species is grown as potted plant and for cut flower production. In March 2016, symptoms of a previously unknown blight were observed on 7-month-old potted plants of C. officinalis. Plants were growing in a farm located in Albenga (Savona Province). Symptoms appeared on leaves, petioles, stems, and inflorescences. Affected leaves and petioles appeared chlorotic and later became rotted, starting from the inside foliage. A soft, gray mycelium appeared on symptomatic tissues, especially on leaves inside the foliage. Stems appeared dark and necrotic. Ligules of inflorescences rolled, wilted, and desiccated. Severely affected plants eventually died. Approximately 30% of 2,500 plants presented the symptoms. Diseased tissues were excised and immersed in a solution of sodium hypochlorite (1%) for approximately 10 s, then washed in sterilized water. Successively, small pieces of affected leaves, petioles, stems, and ligules were cultured on potato dextrose agar (PDA) medium, incubated at temperatures ranging from 20 to 23°C. A fungus developed constantly and produced branched conidiophores with unicellular, ovoid conidia measuring 12.7 to 7.7 × 9.1 to 5.4 (average 9.6 × 7.2) µm. Colonies, stored for approximately 20 days at 8 ± 1°C, produced dark, spheroidal to elongated sclerotia measuring 0.5 to 2.1 mm. These characteristics allowed to identify the isolates from C. officinalis as Botrytis cinerea (Ellis 1971). The internal transcribed spacer (ITS) region of rDNA for the isolate DB16APR03 recovered from an affected leaf was amplified using the primers ITS1/ITS4 (White et al. 1990) and sequenced. BLAST analysis (Altschul et al. 1997) of the 455-bp sequence (GenBank accession KX458182) had 100% similarity with several sequences of B. cinerea, among these KT582111. To confirm pathogenicity, three 9-month-old healthy plants of C. officinalis were artificially inoculated with the isolate DB16APR03. A conidial and mycelial suspension (4 × 105 conidia and mycelial fragment/ml) obtained from 10-day old PDA pure cultures of the pathogen was sprayed on leaves (25 ml/plant). Three control plants were sprayed with sterilized water only. All plants were maintained inside a climatic chamber, in a high humidity chamber for 5 days, at 26 to 27°C (daily average temperatures) and 76 to 88% RH. Four days after the inoculation, first symptoms of chlorosis appeared only on inoculated leaves that, successively, diseased. About 11 days after the inoculation, all inoculated plants appeared desiccated, whereas controls remained healthy. Before inoculated plants died, B. cinerea was easily reisolated from affected tissues. No colonies developed from reisolations attempted from controls. B. cinerea was reported on C. officinalis in the United States (Cash 1953), Scotland, and China. This is the first report of B. cinerea on C. officinalis in Italy. The economic importance of this disease might increase, due to the increasing production of C. officinalis in Italy, especially as potted plant.

Effect of Vapor-Deposited Parylene Coating on Reliability of Sintered Silver Joints for Extreme Temperature Applications

Abstract Silver nano-particle (AgNP) sintering has been extensively shown to be an excellent bonding method for use in the assembly of high-temperature multi-chip modules (MCM) rated above 200° C. Among the proven advantages of using this material in the assembly are the high mechanical strength of the attachment joints, resilience to thermal cycles, low resistivity, and high thermal conductivity. One of the concerns related to the reliability of sintered silver joints is silver migration. Another concern is the change in the joint's microstructure under thermal stress. Vapor-deposited high-temperature fluorinated parylene coating (Paralyne HT) may have the potential to mitigate those concerns because of its superior conformal and crevice-penetration properties. In this work, impact of Parylene HT on sintered silver joints has been evaluated from the perspective of mechanical strength. Test vehicles were subjected to thermal cycling and high-temperature aging. To understand the sintered silver joint's failure mechanisms, shear test analysis of the cross sections and fracture surfaces was performed. In addition, the effectiveness of Parylene HT as a coating to inhibit silver migration at high humidity was evaluated. Coated and uncoated sintered silver test patterns were stressed with an electrical field inside a high-humidity chamber. The silver migration progression was monitored and compared between coated and uncoated samples during the test. One of the findings was that the coating material penetrates the pores of the sintered silver joints, altering their mechanical performance under thermal stress. Analysis of the performance differences between coated and uncoated test vehicles is presented in the paper.

Characterization of an acrylic polymer under hygrothermal aging as an optically clear adhesive for touch screen panels

Optically clear adhesives (OCAs) are key components of touch screen panels (TSPs). It is important that OCAs do not affect the transparent electrodes in TSPs because OCAs are contacted to the transparent electrodes. Therefore, N-vinyl caprolactam (NVC) was incorporated in the composition of an acrylic pressure sensitive adhesive (PSA) with excluding an acidic component to maintain the cohesion for OCA preparation. With increasing amounts of NVC, the tack and peel strength of UV-cured PSA increased, but high amounts of NVC led to decreased peel strength. The UV-cured PSA films were placed in a high temperature and humidity chamber for 8 weeks to investigate the durability and corrosion property under hygrothermal conditions. In this study, the corrosion test method using copper foil was suggested as a simple and economical method and was used to evaluate the effect of NVC on the corrosion property of PSA. This method helped identify suitable OCAs that do not have corrosive property. PSA films containing more than 20wt% of NVC promoted the corrosion of copper foil under hygrothermal aging conditions. The caprolactam ring was opened by moisture, and the PSA structure morphed into a polar structure during the aging process. This change caused a glass transition shift, an increase in the storage modulus at the rubbery plateau, and an increase in peel strength. The surface free energy of the PSA films also increased due to the increase in the polar property. However, high amounts of NVC caused a decrease in the peel strength after 8 weeks of aging because of increased molecular interactions.

Controlled Humidification of Sweet Potato Stem-Cuttings in a Self-Sustaining Humidifier: Effects on Vigour, and Implications for Climate Change

Predictions of extreme weather associated with global warming signify potential extremes in soil water content, and extremes of soil water tension are inimical to early plant growth. Periderm tissue [cork cells], being waterproof, restricts root and stem waterlogging whilst the promotion of early roots better prepare stem cuttings for survival in dry soils. Sweet potato stem cuttings were stored for up to six days in a chamber humidifier. Humidification was achieved by evaporation up to saturation vapour pressure [SVP] in a closed system of capillary water evaporating from a fabric which enclosed the cuttings. Treatments included vine cuttings stored (1) under grass clippings (traditional treatment) and (2) inside a high humidity (100%) chamber. Root growth occurred on 90% of the cuttings in the root length sequence: 9-, 28-, 47 mm after 3, 6 and 9 days respectively in the 100% humidity chamber at an average ambient room temperature of 25 oC. Under traditional treatments, root growth occurred on only 10% of the cuttings and was 0.5-, 2-, and 3 mm after 3, 6 and 9 days respectively. Traditional treatment did not exhibit observable periderm (cork cells) growth at any stage of the study. Periderm thicknesses of 3-, 7-, and 9mm occurred on days 3, 6, and 9 for samples held at 100% humidity. No periderm was observed for the traditionally treated samples. For field trials, the most vigorous growth in a dry soil was observed for cuttings previously subjected to chamber humidification, an important asset when early season weed competition is evident and when rapid ground cover is important. In a broader perspective, these results can be used to optimize studies of other crops grown from cuttings.

A Technique to Study Meloidogyne arenaria Resistance in Agrobacterium rhizogenes-Transformed Peanut.

A reliable peanut root transformation system would be useful to study the functions of genes involved in root biology and disease resistance. The objective of this study was to establish an effective protocol to produce composite plants mediated by Agrobacterium rhizogenes transformation. In total, 75% of transformed peanut seedlings produced an average of 2.83 transgenic roots per plant. Peanut seed had the highest germination rate after treatment in a chlorine gas chamber for 8 h compared with 16 h in chlorine gas or Clorox and mercuric chloride immersion treatments. High transformation efficiency was achieved when the wound site for A. rhizogenes inoculation was covered with vermiculite instead of enclosing the whole plant in a high humidity chamber. On average, 2.5 galls from Meloidogyne arenaria infection were formed per transgenic root from susceptible genotype TifGP-2. These data indicate that A. rhizogenes-transformed roots can be used to phenotype the host response to nematode challenge. Transformation of RLP-2, a candidate resistance gene for M. arenaria integrated into a silencing construct, did not alter the resistance response of Tifguard, even though downregulation of endogenous RLP-2 expression was detected in transformed roots. It is likely that RLP-2 is not the gene conditioning M. arenaria resistance in peanut.

First Report of Forsythia Shoot Blight Caused by Phytophthora nicotianae in Connecticut

Blighting of Forsythia × intermedia 'Showoff' was first observed affecting several hundred plants in a commercial nursery in Connecticut in September 2012. Symptoms included wilting, leaf and stem blight, and dieback progressing to plant death. A Phytophthora sp. was isolated from symptomatic tissues on half-strength potato dextrose agar (½PDA). Colonies were white and cottony on ½PDA, reaching 9 mm in 15 days at 25°C, but colorless and inconspicuous on pimaricin, ampicillin, rifampicin, pentachloronitrobenzene agar (PARP) with sparse and limited aerial mycelium, reaching 60 mm in 15 days at 25°C. The characteristics of the pathogen were observed and measured from a 3-month-old colony on ½PDA. Sporangia were abundant, various in shape, ovoid, ellipsoid to pyriform or limoniform, occasionally gourd shaped or irregular; (17.9) 27.2 to 41.4 (47.3) × (12.6) 19.1 to 30.5 (36.7) μm (n = 30), length/breadth ratio 1.4 ± 0.2, papillate and noncaducous. Papillae measured 2.9 ± 0.8 × 3.4 ± 0.8 μm (n = 10). Chlamydospores were present, 23.4 ± 3.1 × 22 ± 3.3 μm (n = 10). Oogonia and oospores were not observed. Arachnoid mycelia were present. These morphological characteristics are consistent with Phytophthora nicotianae Breda de Haan (1). The identity of the pathogen was confirmed as P. nicotianae by BLAST analysis of ITS, Cox II, and beta tubulin gene sequences (99% match for the three sequences, E value = 0). Pathogenicity tests were conducted four times on healthy liners of Forsythia × intermedia 'Showoff' grown in 10-cm-diameter pots. Leaves and stems were wounded by pricking with a sterile needle and six plants were inoculated with 0.25 cm2 plugs of the pathogen growing on ½PDA placed on three leaves and in three stem nodes and covered with Parafilm. Controls consisted of an equal number of plants wounded and inoculated with ½PDA alone. All plants were placed inside high humidity chambers for 24 h and then transferred to a greenhouse for up to 1 month. Typical symptoms developed within 1 week of inoculation and the pathogen was re-isolated from diseased tissue. Disease incidence was nearly 100% of inoculated leaves and stems and not observed in control plants without the pathogen. Three replicate 6-week-old broadleaf tobacco 'C9' plants were each inoculated with tobacco or forsythia isolates of P. nicotianae or sterile media alone, by wounding stems and placing colonized 0.25 cm2 ½PDA plugs into wounds and covering with Parafilm. After 1 week, stems were split and the length of internal necrosis in the stem measured. Disease resulted from inoculation with both the tobacco and forsythia isolates and stem necrosis averaged 43 and 23 mm for tobacco or forsythia isolates, respectively. No necrosis was observed in the pathogen-free controls. P. nicotianae has been reported from the basal stem and roots of F. viridissima in Italy (2) and from shoots of Forsythia × intermedia in Virginia (3). To our knowledge, this is the first report of P. nicotianae causing shoot blight on Forsythia in the northeastern United States.

Size stabilization of surface-supported liquid aerosols using tapered optical fiber coupling

We demonstrate long-term size stabilization of surface-supported liquid aerosols of salt-water. Single tapered optical fibers were used to couple the light from independent heating and probe lasers into individual microdroplets that were kept on a superhydrophobic surface in a high-humidity chamber. Size stabilization of microdroplets resulted from competition between resonant absorption of the infrared heating laser by a microdroplet whispering gallery mode and water condensation in the sample chamber. Microdroplet size was continuously monitored using the tunable red probe laser. Thanks to the narrow linewidth of the heating laser, stabilization of the 110 μm radius of a microdroplet with a precision down to 0.54 nm was achieved for a period of 410 s.

First Report of Leaf Spot of Fan Columbine (Aquilegia flabellata) Caused by Phoma aquilegiicola in Italy.

Aquilegia flabellata (Ranunculaceae), fan columbine, is a perennial herbaceous plant with brilliant blue-purple flowers with white petal tips that is largely present in gardens. It can also be grown for cut flower production. In September of 2008 and 2009, in a private garden located near Biella (northern Italy), a leaf blight was observed. Leaves of infected plants showed extensive, irregular, brown, necrotic lesions, which were slightly sunken with a well-defined border and surrounded by a violet-brown halo. A hole frequently appeared in the center of dried tissues. Lesions, initially measuring 0.5 mm, later expanded up to 15 mm in diameter and eventually coalesced to cover the entire leaf, which curled without falling. At a later stage, stems were also affected, causing death of the apical part of the plant. The disease affected 90% of the plants in the garden. Dark brown, subglobose pycnidia, 116 to 145 μm, containing light gray, ellipsoid, nonseptate conidia measuring 9.0 to 16.2 × 2.6 to 4.2 (average 12.7 × 3.4) μm were observed on symptomatic tissue. On the basis of these morphological characteristics, the fungus was related to the genus Phoma (2). Diseased tissue was excised from the margin of lesions, rinsed in sterile distilled water, and then cultured on potato dextrose agar (PDA) medium at 23 ± 1°C under alternating daylight and darkness (12-h light and 12-h dark). Fungal colonies produced a pale olive green, lightly floccose mycelium, generating clusters of dark olive green swollen cells. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 504-bp segment showed 100% homology with a sequence of Phoma aquilegiicola (GenBank Accession No. GU237735). The nucleotide sequence of our isolate was assigned GenBank Accession No. HM222537. Pathogenicity tests were performed by spraying a mycelium suspension of a homogenate of mycelium (1 × 105 mycelial fragments per ml) obtained from 15-day-old PDA cultures of the fungus on leaves of six healthy 6-month-old potted A. flabellata plants. Six plants inoculated with a homogenate of PDA served as controls. Plants were maintained in a greenhouse in a high humidity chamber for 7 days after inoculation at 23 ± 1°C and under high relative humidity conditions (70 to 90%). The first foliar lesions developed on leaves 4 days after inoculation. After 15 days, 80% of the leaves were severely infected. Control plants remained healthy. The organism reisolated on PDA from leaf lesions was identical in morphology to the isolate used for inoculation. The pathogenicity test was carried out twice. To our knowledge, this is the first report of the presence of P. aquilegiicola on A. flabellata in Italy. Ascochyta aquilegiae (synonym P. aquilegiicola) has been reported on A. vulgaris in Germany (4) and Aquilegia spp. in the United States (3). Currently, the economic importance of this disease is limited, but may become a more significant problem if the use of A. flabellata in gardens increases.

First Report of Leaf Spot of Orange Coneflower (Rudbeckia fulgida) Caused by a Phoma sp. in Italy.

Rudbeckia fulgida (orange coneflower) is an herbaceous species (Asteraceae) grown in full sun in flower beds and borders in gardens. In the summer of 2009, a previously unknown leaf spot was observed on R. fulgida plants in three private gardens located near Biella (northern Italy). Leaves of infected plants showed extensive and irregular, dark brown, necrotic lesions that were slightly sunken with a well-defined border. Lesions initially ranged from 0.5 to 3 mm in diameter and eventually coalesced to cover the entire leaf, which curled without falling. At a later stage, stems were also affected, causing death of the plant. The disease affected 90% of plants. Dark brown pycnidia, 68 to 195 × 60 to 165 (average 135 × 117) μm in diameter, containing hyaline (light gray in mass), and ellipsoid, nonseptate conidia measuring 4.0 to 7.0 × 2.4 to 3.5 (average 5.4 × 3.0) μm were observed on symptomatic tissue. On the basis of these morphological characteristics, the fungus was related to the genus Phoma. Diseased tissue was excised from the margin of lesions, immersed in a solution containing 1% sodium hypochlorite for 2 to 3 s, rinsed in sterile distilled water, and then cultured on potato dextrose agar (PDA) medium. Fungal colonies initially produced a white mycelium that became greenish gray when incubated at temperatures ranging between 22 and 25°C under alternating daylight and darkness (13 h of light and 11 h of dark). After 14 days of incubation, unicellular, cylindrical or truncated cone-shaped, light brown chlamydospores measuring 6 to 12 μm in diameter developed in long chains. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 498-bp segment showed 100% homology with a sequence of a Phoma sp. (EF585395). The nucleotide sequence of our isolate was assigned GenBank Accession No. GU573979. Pathogenicity tests were performed by placing 100 ml of a water homogenate of mycelium (1 × 105 mycelial fragments/ml) obtained from 15-day-old PDA cultures of the fungus on leaves of three healthy 4-month-old potted R. fulgida plants. Three plants inoculated with a homogenate of PDA served as controls. Plants were maintained in a greenhouse, in a high humidity chamber for 7 days after inoculation, at temperatures ranging from 18 to 22°C and under high relative humidity conditions (70 to 90%). The first foliar lesions developed on leaves 7 days after inoculation, and after 10 to 12 days, 80% of leaves were severely infected. Control plants remained healthy. The organism reisolated on PDA from leaf lesions was identical in morphology to the isolate used for inoculation. The pathogenicity test was carried out twice. To our knowledge, this is the first report of the presence of a Phoma sp. on R. fulgida in Italy. Mycosphaerella ligulicola was reported on Rudbeckia sp. (2), while M. rudbeckiae and Phoma exigua have been reported on R. hirta (3). Currently, the economic importance of this disease is limited, but may become a more significant problem if the cultivation of this species increases.

Suppression of Botrytis bunch rot in Chardonnay grapevines by induction of host resistance and fungal antagonism

A chemical elicitor, 5-chlorosalicylic acid (5C SA), and a fungal antagonist Ulocladium oudemansii, were evaluated for their ability to suppress Botrytis cinerea in Chardonnay grapes. Potted plants developed resistance to B. cinerea infection after treatment with 1 mM 5CSA. Resistance, as expressed by a reduction in lesion diameter, was greatest in plants that were treated with 5CSA 7 days before inoculation. This delayed response is indicative of induced resistance and this is supported by observations that 1 mM 5CSA did not significantly affect B. cinerea growth on amended media or on treated necrotic leaf disks. Compatibility studies on necrotic leaf disks demonstrated that 5CS A had no significant adverse effects on U. oudemansii conidial germination, germ tube vigour and B. cinerea suppression, indicating that these two components could be mixed for field use. Applications of 5C SA, U. oudemansii and 5CSA + U. oudemansii, every 10–14 days from flowering until one week pre-harvest significantly (P < 0.05) reduced Botrytis bunch rot severity on Chardonnay grapevines. Disease severity at harvest was significantly lower on treated bunches than on untreated controls. There was no significant difference between stand-alone and combination treatments at vintage. Harvested bunches were incubated in high humidity chambers to encourage Botrytis bunch rot development. After 14 days incubation, Botrytis severity increased to 83% on untreated bunches compared with between 37–41% on those treated with 5CSA and U. oudemansii Under these conditions 5CSA+ U. oudemansii provided significantly better control than each component alone and reduced bunch rot severity to less than 15.2%. The potential deployment of elicitors and antagonists to control Botrytis bunch rot in grapes is discussed.

Changes in root water flow properties of solution culture-grown trembling aspen (Populus tremuloides) seedlings under different intensities of water-deficit stress.

To study the effects of water-deficit stress on root water flow properties in trembling aspen (Populus tremuloides Michx.), seedlings were grown in solution culture and subjected to water-deficit stress by placing their roots in sealed high humidity chambers. After 17 h of stress treatment, seedlings showed mild stress (MS) symptoms with a decline in shoot water potentials. Within 20 h, shoot water potentials rapidly declined, and severe stress (SS) symptoms were present. Root hydraulic conductivity (L(pr)) increased more than two-fold and the relative concentration of apoplastic tracer dye trisodium 3-hydroxy-5, 8, 10-pyrenetrisulphonate (PTS(3)) in xylem exudate decreased by 73.6% in MS seedlings. Conversely, L(pr) decreased (55.3%) and PTS(3) increased (28.6%) in SS seedlings. Treatment of roots with 0.1 mM mercuric chloride decreased root volume flow density (J(v)) by about 29.0% in control and MS plants with no decrease measured in SS seedlings. Mercuric chloride also increased PTS(3) concentration in xylem exudate of control (59%) and MS (86%) seedlings with no change observed in SS plants. The results suggest that aquaporin-mediated transport is important in the regulation of root water flow under drought stress and that root water flow properties are strongly affected by the stress level. Regulation of root water flow may represent an important drought-stress resistance mechanism.

Behavior of Listeria monocytogenes in a Pseudomonas putida Biofilm on a Condensate-Forming Surface

Listeria monocytogenes has been isolated from condensate-forming surfaces in food processing plants. The objective of this research was to observe the behavior of L. monocytogenes on condensate-covered stainless steel with a Pseudomonas putida biofilm. L. monocytogenes–containing biofilms, either with or without added chicken protein, were incubated in a high humidity chamber at 12°C to allow formation of condensate. Samples were analyzed for attached and unattached L. monocytogenes and total plate count periodically for 35 days. Samples were also taken for microscopic observation of Listeria and bacterial extracellular polymeric substances (EPS). L. monocytogenes attached in significantly greater numbers (>3-log difference) to surfaces with preexisting P. putida biofilms than to Pseudomonas-free surfaces. L. monocytogenes survived in the presence or absence of P. putida with no added nutrients for 35 days, with numbers of survivors in the range of 3 to 4 log CFU/cm2 in the presence of P. putida and less than 2.9 log CFU/cm2 in pure culture. Attached and unattached L. monocytogenes were at similar levels throughout the incubation under all conditions studied. The addition of protein to the biofilms allowed growth of L. monocytogenes in pure culture during the first 7 days of incubation. Numbers of L. monocytogenes were not affected by the presence of P. putida when protein was present. Unattached L. monocytogenes were at levels of 3.6 to 6.7 log CFU/cm2 on the protein-containing surfaces. Microscopic observation of the condensate-covered biofilms indicated that L. monocytogenes formed microcolonies embedded within an EPS matrix over a 28-day period. This research demonstrates that L. monocytogenes can survive on condensate-forming stainless steel in low and high nutrient conditions, with or without the presence of Pseudomonas biofilm. The Listeria can detach and, therefore, have the potential to contaminate product.

ＳｎＺｎ系鉛フリーはんだのＳＭＴの温度サイクル疲労並びに曲げ疲労による劣化特性

To know the characteristic reliability of SnZn soldering joints, we investigated with the thermal fatigue life with CSP which has Sn-3Ag-0.5Cu solder balls, and the mechanical fatigue life of soldering joints between Cu or Au/Ni plating on Cu after environmental test. We found that the soldering joints at reflow temperature which is lower than the melting point of Sn-3Ag-0.5Cu solder, had satisfied thermal fatigue life. However the soldering joints between Cu platings, which stored in the high temperature and high humidity chamber, had short mechanical fatigue life.

First Report of Bipolaris sorghicola on Johnsongrass in Argentina.

Target leaf spot was found on johnsongrass (Sorghum halepense (L.) Pers.) in La Plata, Argentina (34°54'S, 58°30'W). Up to 80% disease severity was observed in adult plants. In most diseased plants, spots were well defined, delimited by leaf veins, and elongated. Individual lesions ranged in size from small spots (2 to 3 mm) to large lesions (10 to 15 mm). Lesions sometimes coalesced to produce extensive areas of necrosis. Isolates identified as Bipolaris sorghicola (Lefebre & Scherwin) Alcorn (1) grew slowly on potato dextrose agar medium, producing a compact dark brown mycelium. Conidia were 40 to 80 μm long, slightly curved and golden brown, with three to seven pseudosepta. Although germination of conidia was mainly bipolar, lateral germination sometimes was observed. Twenty monoconidial isolates were inoculated at 105 conidia per cm3 on johnsongrass at the 4-leaf stage to confirm the pathogenicity of B. sorghicola. After inoculation, plants were placed in a high-humidity chamber for 24 h; thereafter, they were kept at 25°C day and 18°C night temperatures. Typical lesions developed after 10 days. The pathogen was reisolated from lesions after 15 days. Johnsongrass is one of the most noxious weeds in the world. Due to its potential as a biocontrol agent, further studies are needed to determine the effect of B. sorghicola on johnsongrass. Reference: (1) J. L. Alcorn. Mycotaxon 27:1, 1983.