scholarly journals A Foliar Disease of European Hackberry Endemic in Sicily

Plant Disease ◽  
2000 ◽  
Vol 84 (4) ◽  
pp. 492-492 ◽  
Author(s):  
S. O. Cacciola

European hackberry (Celtis australis L.; Ulmaceae), a semideciduous tree or shrub that produces small edible berries was originally grown in Italy to produce charcoal and timber and was particularly suitable for making whipstocks, carriage wheel spokes, and hoe handles. European hackberry is currently used for reforestation and as shade trees in parks and roadside plantings. Recently, a foliar disease caused by the dematiaceous hyphomycetous fungus Sirosporium celtidis (Biv.-Bern. ex Sprengel) M.B. Ellis on hackberry saplings in a nursery was observed in the Piedmont Region (northern Italy) by Giannetti et al. (2), who referred to it as a rare disease. However, during a survey in the nature reserve of the Anapo River Valley, in the Sicily Region (southern Italy), where European hackberry and a closely related species (C. tournefortii Lam.) grow naturally, most hackberry plants were found to be infected by S. celtidis, with variable intensity. During autumn, symptoms appeared on lower leaf surfaces as reddish brown to dark black-brown subcircular velvety spots (up to 10 to 15 mm wide) surrounded by narrow paler margins that were evenly distributed over the leaf surface and later confluent. Nonspecific symptoms on upper leaf surfaces were visible only in advanced stages and consisted of necrotic areas, usually apical or marginal, that were at first red-brown and later turned gray. A few trees were prematurely defoliated. Usually, however, severely affected leaves were necrotic, withered, and curled but remained attached. Spots on lower leaf surfaces were covered by mycelium, conidiophores, and conidia that corresponded to the description of S. celtidis published by Ellis (1). Conidia were straight, flexuous, occasionally markedly curved or coiled, cylindrical or obclavate, smooth, wrinkled or verrucose, subhyaline to golden or reddish brown, typically multicellular with 1 to 32 transverse septa, and occasionally had longitudinal or oblique septa that were often constricted, more than 100 μm long and up to 5 to 8 μm thick, with an inconspicuous scar at the base. From 1997 to 1999, infection by S. celtidis in the Anapo River Valley occurred each year, probably favored by the moist environment. S. celtidis, first described in Sicily as early as 1815 (1), has been recorded on various hackberry species in many countries, including the United States (3). Apparently this pathogen is of little economic and ecological significance in natural ecosystems; however, the fungus could become a serious problem in nurseries (2). References: (1) M. B. Ellis. 1963. Mycological Papers, No. 87. Commonw. Mycol. Inst. Kew, England. (2) G. Giannetti et al. Inform. Fitopatol. 49:39, 1999. (3) D. H. Linder. Ann. Mo. Bot. Garden 18:31, 1931.

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1826-1826 ◽  
Author(s):  
M. Berbegal ◽  
A. Pérez-Sierra ◽  
J. Armengol

Hackberry (Celtis australis L.) is widely used for reforestation and as shade tree in parks and roadside plantings in southern Europe (4). In autumn 2011, a foliar disease was observed affecting several trees planted in a garden area located in Alzira (Valencia province, eastern Spain). Symptoms appeared on lower leaf surfaces as reddish to dark brown velvety irregular spots, later becoming grayish brown on the upper surface. Most of the infected trees were prematurely defoliated. Spots on lower leaf surfaces were covered by mycelium, conidiophores, and conidia. Fungal isolates were recovered directly from the structures present on the lesions and by surface-disinfecting small fragments of symptomatic leaf tissue in 0.5% NaOCl, double-rinsing the sections in sterile water, and plating the sections onto potato dextrose agar (PDA) amended with 0.5 g of streptomycin sulfate per liter. Single conidium cultures made onto PDA were maintained for 2 months at 25°C in darkness for morphological examination. Conidia were thick walled, dark reddish brown, often markedly curved or coiled, cylindrical to obclavate, smooth, wrinkled, or verrucose, typically multicellular, 2 to 40 transversely septate and occasionally with 1 to 3 longitudinal or oblique septa that were often constricted, 20 to 96 (44.9) × 6 to 9 (7.1) μm, with an inconspicuous scar at the base. Morphological characters corresponded to the description of Sirosporium celtidis (Biv. ex Spreng) M. B. Ellis published in 1963 (3). The internal transcribed spacer (ITS) region of the rDNA was amplified with the primers ITS1 and ITS4 from DNA extracted from the isolate AL1, and sequenced (GenBank Accession No. JX397963). The sequence was identical to that obtained from an isolate of S. celtidis from the Centraalbureau voor Schimmelcultures, Utrecht, The Netherlands (CBS 289.50). Pathogenicity tests were conducted on five 2-year-old hackberry trees by spraying onto the upper and lower leaf surfaces a conidial suspension of S. celtidis (approximately 50 ml/plant, 106 conidia/ml of water). Five control plants were sprayed with sterile water. Plants were covered with clear plastic bags and incubated in a growth chamber for 72 h at 25°C with a 12-h photoperiod. First leaf spots were visible on inoculated plants after 7 days, but symptoms were not observed on control plants. The fungus was reisolated from leaf lesions on inoculated plants, confirming Koch's postulates. S. celtidis was first described in Sicily in 1815 (3) and has been recorded on various hackberry species in Mediterranean countries and the USA (1,2). To our knowledge, this is the first report of the disease in Spain. The economic and ecological significance of the pathogen in natural ecosystems in Spain remains to be determined but it could certainly become a serious problem for nurseries and urban plantings. References: (1) S.O. Cacciola. 2000. Plant Dis. 84, 492. (2) D. H. Linder. 1931. Ann. Mo. Bot. Garden 18, 31. (3) M. B. Ellis. 1963. Mycological Papers, No. 87. Commonw. Mycol. Inst. Kew, England. (4) S. Pauleit et al., Urban For. Urban Green. 1:83, 2002.


2021 ◽  
Vol 2021 (23) ◽  
pp. 237-250
Author(s):  
Anatolii Morozov ◽  
◽  
Tetiana Morozova ◽  
Inessa Rutkovska ◽  
◽  
...  

Introduction.The main environmental risks posed by roads are population depletion (deaths on roads) and barrier effects (habitat fragmentation). Barrier effects - animals avoid crossing roads, which leads to a decrease in the size and quality of habitat, optimal population size, reduced ability to find food and partner, increased genetic structuring and local extinction (Forman et al. 2003; Andrews et al. 2015; van der Ree et al. 2015). These risks against the background of other stressors, in particular the presence of invasive species, pollution, pesticide use, climate change, plant and animal diseases, may threaten the survival of populations.This issue is especially relevant for herpetofauna due to their biological characteristics. In particular, reptiles and amphibians move slowly, are too small (for drivers to see), do not avoid roads, and in cold periods roads attract amphibians (thermoregulation) because the coating absorbs and retains heat (Case and Fisher 2001; Jochimsen et al. 2004).The principle of ensuring ecological continuity is to identify priority efforts to mitigate environmental risks for animals and reduce the negative impact of the transport complex as a spatial barrier and source of pollution by introducing a number of technical means (eco-crossings, screens, embankments, landscaping). As it is not possible to change the environmental risks on all roads and for all species at present, it is necessary to identify the most vulnerable species, assess the risks to populations and the need for mitigation based on analysis of road density and traffic intensity.Problem Statement. With the advent of land transport there was a progressive environmental problem - the transformation of landscapes, it first appeared in countries with developed road infrastructure in Western Europe and the United States, and quickly spread around the globe (Ellenberg, et al., 1981; Fetisov, 1999; Zagorodnyuk, 2006, Ilyukh, Khokhlov, 2012). Numerous publications by both foreign and domestic authors are devoted to the study of the impact of transport infrastructure. Special attention of European authors is paid to the study of the phenomenon of fragmentation of natural ecosystems. In Europe, there is a network of experts and institutions of IENE, which is studying the possibility of implementing preventive measures for landscape fragmentation, promotes the development of transport infrastructure in accordance with environmental requirements, by creating a safe, environmentally sustainable European transport infrastructure.The ecological trail of the road network significantly exceeds its length (Vozniuk, 2014). This is due to the effects of, in particular, mortality on the roads of mammals, reptiles, reptiles (Forman et al. 2003), landscape fragmentation (roads divide the area into isolated areas, with low populations (sometimes below the minimum), so such populations lose genetic diversity and may become extinct locally), the loss of habitats of species and a decrease in the level of connectivity. In addition to these obvious effects, noise and vibration pollution are added, which inhibit the ability of reptiles, birds and mammals to detect prey or avoid predators (Forman et al. 2003), disturbed light regime (Rich and Longcore 2006). Roads contribute to the development of soil erosion processes, the spread of invasive and introduced species (300-800 seeds/m2 per year are transported to roadside ecotones by vehicles (Von der Lippe and Kowarik 2007), which contributes to the formation of local pseudo-populations), create obstacles and sources. (Forman et al. 2003).Purpose. Substantiation of the principle of ecological continuity regarding the negative impact of transport infrastructure on natural ecosystems and search for possible ways to minimize and prevent such impact.Materials and methods. The main research methods are the application of theoretical general scientific approaches to study: analysis and synthesis of international and domestic scientific and theoretical works, EU documentation (charters, design requirements), Ukrainian legal framework, literature sources; collection and analysis of statistical data to identify the dangers of the impact of road infrastructure on biodiversity and determine the value of the natural landscape.Results. The result is an analysis of the scientific literature on the negative impact of transport infrastructure on animals, systematization of the main impacts for the preparation of methodological documents for organizations planning and designing transport infrastructure in Ukraine to reduce the negative impact.Conclusions. The principle of ensuring ecological continuity is to minimize the negative consequences for the environment. In particular, by leveling the spatial barrier of the public highway. When laying a road through natural ecosystems, it is necessary to build transitions and passages for animals. In this case, their density and type must correspond to the natural rank of the territory. The construction of crossings for animals should be mandatory for all types of roads that cross ecological corridors. This is especially true for smaller roads, completely devoid of any transitions for animals, noise shields (on such roads are more likely to hit animals). An important point is the need to plan preventive methods at the planning stage of road construction. The analysis of the European experience shows that the negative impact of transport infrastructure on biota can be solved by consolidating the efforts of road transport specialists and specialists in the field of nature protection.Keywords:motor road,wildlife crossing, biodiversity, road infrastructure, ecological continuity


Plant Disease ◽  
2000 ◽  
Vol 84 (8) ◽  
pp. 901-906 ◽  
Author(s):  
Jerald K. Pataky ◽  
Lindsey J. du Toit ◽  
Noah D. Freeman

Maize accessions were evaluated in 1997, 1998, and 1999 to identify additional sources of Stewart's wilt resistance and to determine if reactions differed among accessions collected from various regions of the United States and throughout the world. The distributions of Stewart's wilt reactions rated from 1 (no appreciable spread of symptoms) to 9 (dead plants) were relatively similar among groups of accessions from all regions of the world except for those from the Mid-Atlantic/Ohio River Valley region of the United States, the southern United States, and the northeastern United States. The mean and median Stewart's wilt rating for 1,991 accessions evaluated in 1997 was 4. The mean Stewart's wilt rating for 245 accessions collected from the Mid-Atlantic/Ohio River Valley region was 3.1, which was significantly lower than that for accessions from all other regions. The mean rating for accessions from the southern United States was 3.7, which also was lower than mean ratings for accessions from all other regions. Ratings from trials in 1997 and 1998 were highly correlated (r = 0.87) for 292 accessions and 15 sweet corn hybrid checks evaluated in both years. Of 20 accessions rated below 2 in 1997 and 1998, seven were from Virginia, seven were from the Ohio River Valley or central Corn Belt of the United States, four were from the northern or western Corn Belt of the United States, and two were from Spain. Ratings for these accessions ranged from 1.7 to 3.1 in 1999. Ratings ranged from 2.6 to 3.7 for F1 hybrids of these accessions crossed with one of two susceptible sweet corn inbreds, CrseW30 or Crse16, which were rated 5.7 and 5.4, respectively. Based on the reactions of this collection of germ plasm, it appears that high levels of Stewart's wilt resistance are prevalent only among accessions collected from areas where the disease has been endemic for several years, whereas moderate levels of resistance can be found in accessions collected from nearly everywhere in the world.


Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 696-696 ◽  
Author(s):  
J. A. Crouch ◽  
M. P. Ko ◽  
J. M. McKemy

Downy mildew of impatiens (Impatiens walleriana Hook.f.) was first reported from the continental United States in 2004. In 2011 to 2012, severe and widespread outbreaks were documented across the United States mainland, resulting in considerable economic losses. On May 5, 2013, downy mildew disease symptoms were observed from I. walleriana ‘Super Elfin’ at a retail nursery in Mililani, on the Hawai'ian island of Oahu. Throughout May and June 2013, additional sightings of the disease were documented from the islands of Oahu, Kauai, Maui, and Hawai'i from nurseries, home gardens, and botanical park and landscape plantings. Symptoms of infected plants initially showed downward leaf curl, followed by a stippled chlorotic appearance on the adaxial leaf surfaces. Abaxial leaf surfaces were covered with a layer of white mycelia. Affected plants exhibited defoliation, flower drop, and stem rot as the disease progressed. Based on morphological and molecular data, the organism was identified as Plasmopara obducens (J. Schröt.) J. Schröt. Microscopic observation disclosed coenocytic mycelium and hyaline, thin-walled, tree-like (monopodial branches), straight, 94.0 to 300.0 × 3.2 to 10.8 μm sporangiophores. Ovoid, hyaline sporangia measuring 11.0 to 14.6 × 12.2 to 16.2 (average 13.2 × 14.7) μm were borne on sterigma tips of rigid branchlets (8.0 to 15.0 μm) at right angle to the main axis of the sporangiophores (1,3). Molecular identification of the pathogen was conducted by removing hyphae from the surface of three heavily infected leaves using sterile tweezers, then extracting DNA using the QIAGEN Plant DNA kit (QIAGEN, Gaithersburg, MD). The nuclear rDNA internal transcribed spacer was sequenced from each of the three samples bidirectionally from Illustra EXOStar (GE Healthcare, Piscataway, NJ) purified amplicon generated from primers ITS1-O and LR-0R (4). Resultant sequences (GenBank KF366378 to 80) shared 99 to 100% nucleotide identity with P. obducens accession DQ665666 (4). A voucher specimen (BPI892676) was deposited in the U.S. National Fungus Collections, Beltsville, MD. Pathogenicity tests were performed by spraying 6-week-old impatiens plants (I. walleriana var. Super Elfin) grown singly in 4-inch pots with a suspension of 1 × 104 P. obducens sporangia/ml until runoff using a handheld atomizer. Control plants were sprayed with distilled water. The plants were kept in high humidity by covering with black plastic bags for 48 h at 20°C, and then maintained in the greenhouse (night/day temperature of 20/24°C). The first symptoms (downward curling and chlorotic stippling of leaves) and sporulation of the pathogen on under-leaf surfaces of the inoculated plants appeared at 10 days and 21 days after inoculation, respectively. Control plants remained healthy. Morphological features and measurements matched those of the original inoculum, thus fulfilling Koch's postulates. To our knowledge, this is the first report of downy mildew on I. walleriana in Hawai'i (2). The disease appears to be widespread throughout the islands and is likely to cause considerable losses in Hawai'ian landscapes and production settings. References: (1) O. Constantinescu. Mycologia 83:473, 1991. (2) D. F. Farr and A. Y. Rossman. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ July 16, 2013. (3) P. A. Saccardo. Syllogue Fungorum 7:242, 1888. (4) M. Thines. Fungal Genet Biol 44:199, 2007.


Author(s):  
L. A. Dimeyeva ◽  
V. N. Permitina ◽  
R. E. Sadvokasov ◽  
B. Sh. Kaliyev ◽  
Zh. K. Salmukhanbetova

The article presents the results of mapping ecosystems of the protected area of the Natural Park “Medeu”,located on the northern slope of the Trans-Ili Alatau mountain range. The map of ecosystems and a legend has beencompiled. The legend contains 13 numbers. The largest sections of the legend are the natural ecosystems of the protectedarea and the natural-anthropogenic ecosystems of the buffer zone and the zone of limited economic activity. The habitatsof species from Red Data book of Kazakhstan that form communities (Malus sieversii (Ledeb.) M. Roem., Armeniacavulgaris Lam., Celtis australis subsp. caucasica (Willd.) C. C. Towns. identified, and their brief characteristics are given.


Plant Disease ◽  
1997 ◽  
Vol 81 (11) ◽  
pp. 1333-1333 ◽  
Author(s):  
N. E. El-Gholl ◽  
T. S. Schubert ◽  
S. E. Walker ◽  
J. K. Stone

Plant pathologists in Florida and Oregon have recently found Cylindrocladium colhounii for the first time on two new ornamental plant species. Brown, pinpoint leaf spots were observed on Callistemon rigidus (stiff bottlebrush) in a Florida nursery. C. colhounii was isolated consistently from these lesions. To confirm Koch's postulates, 25 ml of aconidial suspension at 96,000 conidia per ml was used to spray a 38.1-cm branch of C. rigidus. Plants were maintained in a moist chamber at room temperature (25 ± 2°C). Symptoms appeared within 3 days, and included brown, pinpoint spots (1 mm or less) occurring on both leaf surfaces, sunken blotches, and blight. The fungus was consistently reisolated from symptomatic tissue. In Oregon, the first detection of C. colhounii was from leaf spots on Gaultheria procumbens (wintergreen) in a nursery. No proof of pathogenicity was done in Oregon on G. procumbens. C. colhounii has now been reported on 14 host genera in 10 families from Australia, India, Mauritius, South Africa, and the U.S. (FL, HI, LA, NC, OR, SC) (1–4). References: (1) P. W. Crous and M. J. Wingfield. Mycopathologia 122:45, 1993. (2) A. Peerally. Mycotaxon 40:323, 1991. (3) A. Y. Rossman. Mycol. Pap. No. 150, Commonw. Mycol. Inst., Kew, Surrey, England, 1983. (4) J. Y. Uchida and M. Aragaki. Plant Dis. 81:298, 1997.


2005 ◽  
Vol 52 (9) ◽  
pp. 235-242
Author(s):  
J.G. Schulte ◽  
A.H. Vicory

Source water quality is of major concern to all drinking water utilities. The accidental introduction of contaminants to their source water is a constant threat to utilities withdrawing water from navigable or industrialized rivers. The events of 11 September, 2001 in the United States have heightened concern for drinking water utility security as their source water and finished water may be targets for terrorist acts. Efforts are underway in several parts of the United States to strengthen early warning capabilities. This paper will focus on those efforts in the Ohio River Valley Basin.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Zhengxi Tan ◽  
Shuguang Liu

Terrestrial carbon (C) sequestration through optimizing land use and management is widely considered a realistic option to mitigate the global greenhouse effect. But how the responses of individual ecosystems to changes in land use and management are related to baseline soil organic C (SOC) levels still needs to be evaluated at various scales. In this study, we modeled SOC dynamics within both natural and managed ecosystems in North Dakota of the United States and found that the average SOC stock in the top 20 cm depth of soil lost at a rate of 450 kg C ha−1 yr−1in cropland and 110 kg C ha−1 yr−1in grassland between 1971 and 1998. Since 1998, the study area had become a SOC sink at a rate of 44 kg C ha−1 yr−1. The annual rate of SOC change in all types of lands substantially depends on the magnitude of initial SOC contents, but such dependency varies more with climatic variables within natural ecosystems and with management practices within managed ecosystems. Additionally, soils with high baseline SOC stocks tend to be C sources following any land surface disturbances, whereas soils having low baseline C contents likely become C sinks following conservation management.


2011 ◽  
Vol 101 (9) ◽  
pp. 1122-1132 ◽  
Author(s):  
P. A. Paul ◽  
L. V. Madden ◽  
C. A. Bradley ◽  
A. E. Robertson ◽  
G. P. Munkvold ◽  
...  

The use of foliar fungicides on field corn has increased greatly over the past 5 years in the United States in an attempt to increase yields, despite limited evidence that use of the fungicides is consistently profitable. To assess the value of using fungicides in grain corn production, random-effects meta-analyses were performed on results from foliar fungicide experiments conducted during 2002 to 2009 in 14 states across the United States to determine the mean yield response to the fungicides azoxystrobin, pyraclostrobin, propiconazole + trifloxystrobin, and propiconazole + azoxystrobin. For all fungicides, the yield difference between treated and nontreated plots was highly variable among studies. All four fungicides resulted in a significant mean yield increase relative to the nontreated plots (P < 0.05). Mean yield difference was highest for propiconazole + trifloxystrobin (390 kg/ha), followed by propiconazole + azoxystrobin (331 kg/ha) and pyraclostrobin (256 kg/ha), and lowest for azoxystrobin (230 kg/ha). Baseline yield (mean yield in the nontreated plots) had a significant effect on yield for propiconazole + azoxystrobin (P < 0.05), whereas baseline foliar disease severity (mean severity in the nontreated plots) significantly affected the yield response to pyraclostrobin, propiconazole + trifloxystrobin, and propiconazole + azoxystrobin but not to azoxystrobin. Mean yield difference was generally higher in the lowest yield and higher disease severity categories than in the highest yield and lower disease categories. The probability of failing to recover the fungicide application cost (ploss) also was estimated for a range of grain corn prices and application costs. At the 10-year average corn grain price of $0.12/kg ($2.97/bushel) and application costs of $40 to 95/ha, ploss for disease severity <5% was 0.55 to 0.98 for pyraclostrobin, 0.62 to 0.93 for propiconazole + trifloxystrobin, 0.58 to 0.89 for propiconazole + azoxystrobin, and 0.91 to 0.99 for azoxystrobin. When disease severity was >5%, the corresponding probabilities were 0.36 to 95, 0.25 to 0.69, 0.25 to 0.64, and 0.37 to 0.98 for the four fungicides. In conclusion, the high ploss values found in most scenarios suggest that the use of these foliar fungicides is unlikely to be profitable when foliar disease severity is low and yield expectation is high.


2020 ◽  
Author(s):  
Miriam Muñoz-Rojas ◽  
Paulo Pereira

&lt;p&gt;Fire is an essential element of the environment and a vital force for shaping landscapes all around the world. It has a critical role as driver of natural ecosystem processes and many plant communities are fire dependent aros the globe. However, although fire is a natural and regular component of some biomes in the Earth&amp;#8217;s systems, it can become a destructive force when natural ecosystems are disturbed, fire is introduced at a rate not previously experienced, and recovery to a pre-fire state is not possible. Thus, assesing the potentially harmful environmental impacts of fire and building the underlying knowledge required to successfully manage fire makes are crucial in order to understand the role of fire in all its different dimensions. Over the past year, fires in California in the United States and in the Amazon rainforest in Brazil have grabbed the world&amp;#8217;s attention. The increased rates of fire events in some of these areas, mostly attributed to land degradation processes, have led to international concern. More recently, several bushfires all around Australia have had dramatic impacts in the environment with 10 million hectares burned so far, including large portions of the natural environment. These unprecedented fires are predicted to affect to a large extent the soil characteristics, processes and function in several ecosystems. In this presentation, we highlight some of the most recent research published during the last year on the effects of fire on soil functions and the provision of soil ecosystem services. We also showcase some of the possible approaches to protect and conserve soil ecosystems affected by extreme fires and propose available strategies for post-fire management.&lt;/p&gt;


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