scholarly journals Powdery Mildew, Caused by Leveillula taurica, on Matilija Poppy in California

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 329-329
Author(s):  
S. T. Koike
Keyword(s):  
Powdery Mildew ◽  
Cross Sections ◽  
Northern Mexico ◽  
Leveillula Taurica ◽  
Landscape Plants ◽  
Initial Symptoms ◽  
Humidity Chamber ◽  
Advanced Stages ◽  
Symptoms And Signs

Romneya coulteri, known as matilija poppy or coulter's matilija poppy, is a perennial woody shrub (family Papaveraceae) that is native to southern California and northern Mexico. The plant is used in landscape settings and has the largest flowers, measuring up to 16 cm across, of any plant native to California. In August 2006, in Monterey County, CA, landscape plants of R. coulteri were found affected with a powdery mildew disease. Initial symptoms consisted of chlorotic, irregularly shaped, vein-delimited lesions. As disease progressed, grayish white sporulation was visible on lesions on adaxial and abaxial sides of affected leaves. In advanced stages of the disease, lesions expanded up to 2 cm long and the center tissue of the lesions turned necrotic. Symptoms and signs were observed on both mature and younger foliage. The small matilija poppy planting consisted of six or seven plants and all plants were affected by the disease. Epidermal strips from both sides of leaves and leaf cross sections were mounted in drops of lactophenol and aniline blue and examined with a light microscope. These preparations showed that conidiophores developed from endophytic mycelium and emerged through stomates. Conidiophores were sometimes branched and carried one or two conidia. Hyaline, single-celled conidia were dimorphic. Primary (terminal) conidia were lanceolate with distinct apical points and measured 53 to 61 × 17 to 25 μm. Secondary conidia were ellipsoid-cylindric and measured 53 to 67 × 16 to 22 μm. On the basis of these characters, the pathogen was identified as Leveillula taurica (1). Only the anamorph Oidiopsis taurica stage was observed on plants. To prove pathogenicity, diseased leaves were collected from the landscape plantings. One diseased leaf was gently rubbed against one leaf of a potted, healthy matilija poppy. Twelve leaves were inoculated in this way, and plants were kept in a humidity chamber for 48 h and then maintained in a greenhouse (24 to 26°C). After 14 days, chlorotic lesions appeared on inoculated matilija poppy leaves and sporulation of L. taurica was observed several days later. Untreated control plants did not develop powdery mildew. The experiment was repeated and the results were the same. To my knowledge, this is the first report of powdery mildew caused by L. taurica on matilija poppy. There was no indication that the disease affected the growth of the host; however, powdery mildew reduced the quality of the appearance of this ornamental plant. Reference: (1) H. J. Boesewinkel. Bot. Rev. 46:167, 1980.

scholarly journals Characterization of Powdery Mildew Caused by Leveillula taurica on Calla Lily in California

Plant Disease ◽  
2002 ◽  
Vol 86 (2) ◽  
pp. 187-187 ◽  
Author(s):  
S. T. Koike ◽  
P. Beckman
Keyword(s):  
Powdery Mildew ◽  
Cross Sections ◽  
Late Summer ◽  
Tomato Plants ◽  
Leveillula Taurica ◽  
Calla Lily ◽  
Initial Symptoms ◽  
Humidity Chamber ◽  
Advanced Stages ◽  
Powdery Mildew Fungi

Spring calla lily (Zantedeschia spp.), also known as colored or miniature calla, has markedly increased in popularity in recent years, and the production acreage in the central coast counties of California (Monterey, Santa Cruz, and San Benito), therefore, has significantly increased. Commercial plantings of calla lily (Z. albo maculata and Z. rehmannii hybrids) in California have been infected with a powdery mildew for several years, with the disease particularly evident in late summer and fall. In 2001, powdery mildew was again prevalent, and the pathogen was examined in detail. Initial symptoms consisted of chlorotic, circular-to-oval leaf lesions with diffuse margins. As the disease progressed, white sporulation became visible on lesions. In advanced stages of the disease, the center tissue of lesions turned necrotic. For any such lesion, both the corresponding adaxial and abaxial sides of the leaf always exhibited the symptoms of the disease and developed sporulation of the pathogen. Epidermal strips from both sides of leaves and leaf cross sections were mounted in drops of lactophenol and aniline blue and examined with a light microscope. These preparations showed that epiphytic mycelium was absent and all conidiophores developed from endophytic mycelium and emerged through stomata. Conidiophores carried single or sometimes two conidia and were sometimes branched. Hyaline, single-celled conidia were dimorphic. Primary (terminal) conidia were lanceolate with distinct apical points and measured (58-) 67 to 78 (-81) × 14 to 22 μm. Secondary conidia were ellipsoid-cylindric and measured (56-) 58 to 72 × 17 to 22 μm. For both conidial types, length to width ratios were greater than three. Based on these characters, the pathogen was identified as Leveillula taurica (anamorph Oidiopsis taurica). Cleistothecia were not observed. To test whether the calla lily pathogen could infect another known host of L. taurica, diseased calla lily leaves were gently pressed against leaves of potted tomato (Lycopersicon esculentum) plants (2). Inoculated tomato plants were kept in a humidity chamber for 48 h and maintained in a greenhouse (24 to 26°C). After 12 days, chlorotic lesions appeared on inoculated tomato leaves, and sporulation of L. taurica was observed on the lesions. Uninoculated control tomato plants did not develop powdery mildew. To our knowledge, this is the first report of powdery mildew, caused by L. taurica, on calla lily in North America. This disease has been reported on calla lily in South Africa, Spain, Taiwan, Turkey, and Zimbabwe (1,3,4). References: (1) Y.-K. Chen et al. Ann. Phytopathol. Soc. Jpn. 62:580, 1996. (2) J. C. Correll et al. Plant Dis. 71:248, 1987. (3) K. A. Hirata. Host Range and Geographic Distribution of the Powdery Mildew Fungi. Japan Scientific Society Press, Tokyo, 1986. (4) E. Sezgin et al. J. Turkish Phytopathol. 13:111, 1984.

IMPACT OF POWDERY MILDEW (LEVEILLULA TAURICA) ON YIELD AND FRUIT QUALITY OF PROCESSING TOMATOES IN CALIFORNIA

2015 ◽  
pp. 153-158
Author(s):  
B.J. Aegerter ◽  
C.S. Stoddard ◽  
E.M. Miyao ◽  
M. Le Strange ◽  
T.A. Turini
Keyword(s):  
Powdery Mildew ◽  
Fruit Quality ◽  
Leveillula Taurica ◽  
Processing Tomatoes

scholarly journals Advances in Plant Disease Detection and Monitoring: From Traditional Assays to In-Field Diagnostics

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2129 ◽  
Author(s):  
Ilaria Buja ◽  
Erika Sabella ◽  
Anna Grazia Monteduro ◽  
Maria Serena Chiriacò ◽  
Luigi De Bellis ◽  
...  
Keyword(s):  
Emerging Diseases ◽  
Diagnostic Methods ◽  
Preventive Actions ◽  
Initial Symptoms ◽  
New Frontier ◽  
Information And Communication ◽  
Instruments And Techniques ◽  
The Difference ◽  
Asymptomatic Individuals

Human activities significantly contribute to worldwide spread of phytopathological adversities. Pathogen-related food losses are today responsible for a reduction in quantity and quality of yield and decrease value and financial returns. As a result, “early detection” in combination with “fast, accurate, and cheap” diagnostics have also become the new mantra in plant pathology, especially for emerging diseases or challenging pathogens that spread thanks to asymptomatic individuals with subtle initial symptoms but are then difficult to face. Furthermore, in a globalized market sensitive to epidemics, innovative tools suitable for field-use represent the new frontier with respect to diagnostic laboratories, ensuring that the instruments and techniques used are suitable for the operational contexts. In this framework, portable systems and interconnection with Internet of Things (IoT) play a pivotal role. Here we review innovative diagnostic methods based on nanotechnologies and new perspectives concerning information and communication technology (ICT) in agriculture, resulting in an improvement in agricultural and rural development and in the ability to revolutionize the concept of “preventive actions”, making the difference in fighting against phytopathogens, all over the world.

Do changes in light direction affect absorption profiles in leaves?

2010 ◽  
Vol 37 (5) ◽  
pp. 403 ◽  
Author(s):  
Craig R. Brodersen ◽  
Thomas C. Vogelmann
Keyword(s):  
Cross Sections ◽  
Incident Light ◽  
Monochromatic Light ◽  
Diffuse Light ◽  
Spongy Mesophyll ◽  
Light Regimes ◽  
Direct Light ◽  
Direct Measurements ◽  
Leaf Level

Leaf anatomy plays a functional role in propagating light through the leaf; palisade mesophyll has been shown to facilitate the channelling of collimated light deeper into the spongy mesophyll. Direct measurements of the propagation of diffuse light into the leaf, however, are absent. Using chlorophyll fluorescence imaging of leaf cross-sections, we measured light absorption profiles in leaves under direct (collimated), diffuse and low-angle monochromatic light. Low-angle and diffuse light was absorbed closer to the irradiated surface than direct light perpendicular to the surface. The shapes of internal absorption profiles indicated that leaves were influenced by the directional quality of the incident light. In addition, absorption profiles revealed that leaves were not simple light absorbing objects and that cellular anatomy influences the direction of light travelling into the mesophyll. These findings also suggest a mechanism for previously measured differences in leaf level photosynthesis under opposing light regimes.

Constraint-Based Reverse Engineering From Ultrasound Cross-Sections

1997 ◽  
Author(s):  
Jai Menon ◽  
Ranjit Desai ◽  
Jay Buckey
Keyword(s):  
Reverse Engineering ◽  
Cross Sections ◽  
Biomedical Applications ◽  
Engineering Application ◽  
Volume Data ◽  
Cross Sectional ◽  
Reverse Engineer ◽  
Network Bandwidth ◽  
Complex Topology

Abstract This paper extends the “cross-sectional” approach for reverse engineering, used abundantly in biomedical applications, to the mechanical domain. We propose a combination of “projective” and cross-sectional algorithms for handling physical artifacts with complex topology and geometry. In addition, the paper introduces the concept of constraint-based reverse engineering, where the constraint parameters could include one or more of the following: time, storage (memory, disk-space), network bandwidth, Quality of Service (output-resolution), and so forth. We describe a specific reverse-engineering application which uses ultrasound (tilt-echo) imaging to reverse engineer spatial enumeration (volume) representations from cross-sectional data. The constraint here is time, and we summarize how our implementation can satisfy real-time reconstruction for distribution of the volume data on the internet. We present results that show volume representations computed from static objects. Since the algorithms are tuned to satisfy time constraints, this method is extendable to reverse engineer temporally-varying (elastic) objects. The current reverse engineering processing time is constrained by the data-acquisition (tilt-echo imaging) process, and the entire reverse engineering pipeline has been optimized to compute incremental volume representations in the order of 3 seconds on a network of four processors.

Decompression sickness after a highly conservative dive in a diver with known persistent foramen ovale: Case report

2021 ◽  
Vol 51 (1) ◽  
pp. 111-115
Author(s):  
William Brampton ◽  
◽  
Martin DJ Sayer ◽  
◽  
Keyword(s):  
Decompression Sickness ◽  
Position Statement ◽  
Valsalva Manoeuvre ◽  
Foramen Ovale ◽  
Spinal Decompression ◽  
Previous Episode ◽  
The United Kingdom ◽  
Initial Symptoms ◽  
Persistent Foramen Ovale ◽  
Symptoms And Signs

A diver returned to diving, 15 months after an episode of neuro-spinal decompression sickness (DCS) with relapse, after which she had been found to have a moderate to large provoked shunt across a persistent (patent) foramen ovale (PFO), which was not closed. She performed a single highly conservative dive in line with the recommendations contained in the 2015 position statement on PFO and diving published jointly by the South Pacific Underwater Medicine Society and the United Kingdom Sports Diving Medical Committee. An accidental Valsalva manoeuvre shortly after surfacing may have provoked initial symptoms which later progressed to DCS. Her symptoms and signs were milder but closely mirrored her previous episode of DCS and she required multiple hyperbaric oxygen treatments over several days, with residua on discharge. Although guidance in the joint statement was mostly followed, the outcome from this case indicates that there may be a subgroup of divers with an unclosed PFO, who have had a previous episode of serious DCS, who may not be safe to dive, even within conservative limits.

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