scholarly journals Response of Plant Fungal Diseases to Beef Cattle Grazing Intensity in Hulunber Grassland

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 2905-2913
Author(s):  
Yawen Zhang ◽  
Zhibiao Nan ◽  
Xiaoping Xin
Keyword(s):  
Disease Incidence ◽  
Grazing Intensity ◽  
Cattle Grazing ◽  
Average Density ◽  
Plant Diseases ◽  
Large Herbivores ◽  
Adult Cattle ◽  
Disease Occurrence ◽  
Natural Grasslands ◽  
Vegetation Characteristics

The effects of grazing by large herbivores on biodiversity and ecosystem functioning have been extensively studied, whereas how grazing influence plant diseases, especially in natural grasslands, remains poorly understood. Therefore, we undertook a field study regarding a grazing trial in a temperate meadow steppe grassland to investigate mechanisms underlying grazing-host-pathogen interactions. The effects of cattle grazing at different grazing intensities of 0, 0.23, 0.34, 0.46, 0.69, and 0.92 AU/ha (where 1 AU= 500 kg of adult cattle) on the microenvironment, vegetation characteristics, and occurrence of diseases were evaluated. At the population level, the effects of grazing on grassland vegetation characteristics and disease varied with grassland plant species. Compared with nongrazing, grazing directly decreased the average density, coverage, and disease incidence of palatable and edible forages by 51.4, 62.4, and 82.4% in the 0.92 AU/ha treatment but increased the occurrence and prevalence of disease in remaining small herbs by 752.1%. At the community level, with the increase of grazing intensity, the pathogen load of the whole community in grassland was positively related to host coverage. In addition, there was a trend toward increased microtemperature and decreased microhumidity with increased grazing. Although occurrence of plant diseases in natural grasslands is influenced by a range of factors, comprehensive analysis highlighted the major role that cattle grazing intensity plays in the occurrence of plant diseases in natural grasslands. In addition to its direct effect, grazing also indirectly affects disease occurrence by shifting plant community structure and the microenvironment. However, direct effects of grazing intensity affected disease occurrence more than indirect effects.

scholarly journals Vegetation Response to Goats Grazing Intensity in Semiarid Hilly Grassland of the Loess Plateau, Lanzhou, China

2021 ◽  
Vol 13 (6) ◽  
pp. 3569
Author(s):  
Hua Cheng ◽  
Baocheng Jin ◽  
Kai Luo ◽  
Jiuying Pei ◽  
Xueli Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Community Structure ◽  
Plant Growth ◽  
Loess Plateau ◽  
Grazing Intensity ◽  
Gps Tracking ◽  
Growth Stages ◽  
The Loess Plateau ◽  
Vegetation Community ◽  
Natural Grasslands

Quantitatively estimating the grazing intensity (GI) effects on vegetation in semiarid hilly grassland of the Loess Plateau can help to develop safe utilization levels for natural grasslands, which is a necessity of maintaining livestock production and sustainable development of grasslands. Normalized difference vegetation index (NDVI), field vegetation data, and 181 days (one goat per day) of GPS tracking were combined to quantify the spatial pattern of GI, and its effects on the vegetation community structure. The spatial distribution of GI was uneven, with a mean value of 0.50 goats/ha, and 95% of the study area had less than 1.30 goats/ha. The areas with utilization rates of rangeland (July) lower than 45% and 20% made up about 95% and 60% of the study area, respectively. Grazing significantly reduced monthly aboveground biomass, but the grazing effects on plant growth rate were complex across the different plant growth stages. Grazing impaired plant growth in general, but the intermediate GI appeared to facilitate plant growth rate at the end of the growing seasons. Grazing had minimal relationship with vegetation community structure characteristics, though Importance Value of forbs increased with increasing GI. Flexibility in the number of goats and conservatively defining utilization rate, according to the inter-annual variation of utilization biomass, would be beneficial to achieve ecologically healthy and economically sustainable GI.

scholarly journals First Report of Downy Mildew Caused by Plasmopara obducens on Impatiens in California

Plant Disease ◽  
2004 ◽  
Vol 88 (8) ◽  
pp. 909-909 ◽  
Author(s):  
S. N. Wegulo ◽  
S. T. Koike ◽  
M. Vilchez ◽  
P. Santos
Keyword(s):  
United States ◽  
Downy Mildew ◽  
Disease Incidence ◽  
Leaf Tissue ◽  
The United States ◽  
Plant Diseases ◽  
Single Type ◽  
First Report ◽  
Commercial Grower ◽  
Impatiens Walleriana

During February 2004, diseased double impatiens (Impatiens walleriana) plants were received from a commercial grower in southern California. The upper surfaces of symptomatic leaves were pale yellow with no distinct lesions. Diseased leaves later wilted, and severely affected leaves abscised from the stem. At the nursery, only double impatiens plants in the Fiesta series were infected, and some cultivars were more heavily infected than others. Disease incidence in cv. Sparkler Hot pink was nearly 100%. The interior of infected leaves was colonized by coenocytic mycelium. A conspicuous white growth was observed only on the underside of leaves. Sporangiophores were hyaline, thin walled, emergent from stomata, and had slightly swollen bases. Sporangiophore branching was distinctly monopodial. Smaller sporangiophore branches were arranged at right angles to the supporting branches, and tips of branches measured 8 to 14 μm long. Sporangia were ovoid and hyaline with a single pore on the distal ends. Distal ends of sporangia were predominantly flat but occasionally had a slight papilla. Short pedicels were present on the attached ends. Sporangia measured 19.4 to 22.2 (-25.0) μm × 13.9 to 16.7 (-19.4) μm. Oospores were not observed in leaf tissue. On the basis of symptoms and morphology of the organism, the pathogen was identified as Plasmopara obducens J. Schröt. Pathogenicity tests were done on double type cvs. Fiesta, Tioga Red, and Tioga Cherry Red and on single type cvs. Cajun Watermelon and Accent Lilac. Plants were spray inoculated with sporangiospore suspensions (1 × 104 sporangiospores per milliliter), incubated for 24 h in a dew chamber (18 to 20°C), and then maintained in a greenhouse (22 to 24°C). Symptoms and signs of downy mildew developed after 12 days only on inoculated cv. Fiesta plants, and the pathogen morphology matched that of the originally observed pathogen. Nontreated control plants did not develop downy mildew. To our knowledge, this is the first report of downy mildew on impatiens in California. P. obducens is one of two causal agents of downy mildew of impatiens (2,4). The other pathogen, Bremiella sphaerosperma, has dichotomous sporangiophore branching and causes lesions with well-defined margins (2,4). In the United States, the disease has been recorded in the eastern and northeastern states and in Indiana, Minnesota, Mississippi, Montana, and Wisconsin (3). In Canada, the disease has been recorded in Manitoba and Quebec (1). References: (1) I. L. Conners. An Annotated Index of Plant Diseases in Canada and Fungi Recorded on Plants in Alaska, Canada, and Greenland. Research Branch, Canada Department of Agriculture, Publication 1251, 1967. (2) O. Constantinescu. Mycologia 83:473, 1991. (3) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, 1989. (4) G. W. Wilson. Bull. Torrey Bot. Club 34:387, 1907.

scholarly journals Synergistic Antifungal Activity of Graphene Oxide and Fungicides against Fusarium Head Blight In Vitro and In Vivo

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2393
Author(s):  
Xiuping Wang ◽  
Fei Peng ◽  
Caihong Cheng ◽  
Lina Chen ◽  
Xuejuan Shi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Plant Pathogens ◽  
Antimicrobial Agents ◽  
Plant Protection ◽  
Disease Incidence ◽  
Agricultural Science ◽  
Plant Diseases ◽  
Synergistic Activity

Plant pathogens constantly develop resistance to antimicrobial agents, and this poses great challenges to plant protection. Therefore, there is a pressing need to search for new antimicrobials. The combined use of antimicrobial agents with different antifungal mechanisms has been recognized as a promising approach to manage plant diseases. Graphene oxide (GO) is a newly emerging and highly promising antimicrobial agent against various plant pathogens in agricultural science. In this study, the inhibitory activity of GO combined with fungicides (Mancozeb, Cyproconazol and Difenoconazole) against Fusarium graminearum was investigated in vivo and in vitro. The results revealed that the combination of GO and fungicides has significant synergistic inhibitory effects on the mycelial growth, mycelial biomass and spore germination of F. graminearum relative to single fungicides. The magnitude of synergy was found to depend on the ratio of GO and fungicide in the composite. In field tests, GO–fungicides could significantly reduce the disease incidence and disease severity, exhibiting a significantly improved control efficacy on F. graminearum. The strong synergistic activity of GO with existing fungicides demonstrates the great application potential of GO in pest management.

scholarly journals Anthrax in cattle in southern Brazil: 1978-2006

2006 ◽  
Vol 26 (4) ◽  
pp. 243-248 ◽  
Author(s):  
Ana Lucia Schild ◽  
Elisa Simone V. Sallis ◽  
Mauro P. Soares ◽  
Silvia R.L. Ladeira ◽  
Renata Schramm ◽  
...  
Keyword(s):  
Clinical Manifestation ◽  
Southern Brazil ◽  
Diagnostic Laboratory ◽  
Risk Population ◽  
Adult Cattle ◽  
Source Of Infection ◽  
Disease Occurrence ◽  
Acute Form ◽  
Animal Grazing

Ten outbreaks of anthrax occurred in cattle from 1978 to 2006 in southern Brazil, in 5 municipalities on the border with Uruguay, a country where the disease is frequent. The 10 outbreaks represented 0.2% of all bovine specimens received during the period by the Regional Diagnostic Laboratory of the Federal University of Pelotas, causing 267 deaths in a risk population of 6,605 head. The disease affected young and adult cattle mainly during summer. Only one farmer reported that sheep and horses were also affected. Clinically the peracute form was more frequent, but in some outbreaks the acute form with a clinical manifestation period of 6-48 hours was also observed. The source of infection was not established; but the reduced rainfall, associated with low, flat, flooded lands used for agriculture followed by animal grazing after harvest was probably related to the disease occurrence. Annual vaccination is an efficient way to prevent the disease.

scholarly journals Biocontrol of Tomato Fusarium wilt by Trichoderma Species under in vitro and in vivo Conditions

2016 ◽  
Vol 49 (1) ◽  
pp. 91-98 ◽  
Author(s):  
H. Barari
Keyword(s):  
Plant Protection ◽  
Disease Incidence ◽  
Plant Diseases ◽  
Growth And Yield ◽  
Mazandaran Province ◽  
Trichoderma Species ◽  
Tomato Plants ◽  
Geographical Regions

AbstractTrichodermaspp. have long been used as biological control agents against plant fungal diseases, but the mechanisms by which the fungi confer protection are not well understood. Our goal in this study was to isolate species ofTrichoderma, that exhibit high levels of biocontrol efficacy from natural environments and to investigate the mechanisms by which these strains confer plant protection. In this study, efficacy of the native isolates ofTrichodermaspecies to promote the growth and yield parameters of tomato and to manageFusariumwilt disease underin vitroandin vivoconditions were investigated. The dominant pathogen, which causesFusariumwilt of tomato, was isolated and identified asFusarium oxysporumf. sp.lycopersici(FOL). Twenty eight nativeTrichodermaantagonists were isolated from healthy tomato rhizosphere soil in different geographical regions of Mazandaran province, Iran. Underin vitroconditions, the results revealed thatTrichoderma harzianum, isolate N-8, was found to inhibit effectively the radial mycelial growth of the pathogen (by 68.22%). Under greenhouse conditions, the application ofT. harzianum(N-8) exhibited the least disease incidence (by 14.75%). Also, tomato plants treated withT. harzianum(N-8) isolate showed a significant stimulatory effect on plant height (by 70.13 cm) and the dry weight (by 265.42 g) of tomato plants, in comparison to untreated control (54.6 cm and 195.5 g). Therefore, the antagonistT. harzianum(N-8) is chosen to be the most promising bio-control agent forF. oxysporumf. sp.lycopersici. On the base of present study, the biocontrol agents of plant diseases might be exploited for sustainable disease management programs to save environmental risk.

Grazing intensity of cattle on a complex of rangeland communities in Central Australia.

1980 ◽  
Vol 2 (1) ◽  
pp. 76 ◽  
Author(s):  
WA Low ◽  
WJ Muller ◽  
ML Dudzinski
Keyword(s):  
Perennial Grass ◽  
Grazing Intensity ◽  
Cattle Grazing ◽  
Annual Grass ◽  
Range Condition ◽  
Aerial Surveys ◽  
The Mean ◽  
Central Australia ◽  
Free Ranging

Distribution of cattle grazing the rangeland communities of Kunoth Paddock in central Australia was determined from aerial surveys at fortnightly intervals over a 4.5 year period. Mean density throughout the study was 3.5 cattle/km2 and varied between communities from 8.0 cattle/km2 to 0.4 cattle/km2 on the major communities and from 25.6 cattle/km2 to 3.2 cattle/km2 on the minor communities. Cow-days of use were calculated for seasonal intervals to show grazing intensity on the communities over ti~ne. Grazing concentrations throughout the study revealed three groups of utilization levels of the major communities. Foothill fans, Woodlands, Floodplains and Gilgaied plains received about twice the mean grazing intensity for the paddock. Mulga-annual grass received about average grazing intensity and Hills and Mulga-perennial grass received less than half the average grazing intensity. Our sti~dy shows that cattle graze range communities differentially in a free-ranging situation. This information is useful in interpreting results of range condition and trend studies, and also suggests that more uniform utilization of all the communities might be obtained by controlhng grazing distribution.

scholarly journals First Report of Leaf Blight Caused by Septoria allii on Garlic Chives in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 147-147
Author(s):  
J. H. Park ◽  
S. E. Cho ◽  
K. S. Han ◽  
H. D. Shin
Keyword(s):  
Disease Incidence ◽  
Morphological Characteristics ◽  
Its Region ◽  
Leaf Blight ◽  
Plant Diseases ◽  
Cultivated Plants ◽  
Sequence Information ◽  
Conidial Suspension ◽  
Korean Society ◽  
First Report

Garlic chives, Allium tuberosum Roth., are widely cultivated in Asia and are the fourth most important Allium crop in Korea. In June 2011, a leaf blight of garlic chives associated with a Septoria spp. was observed on an organic farm in Hongcheon County, Korea. Similar symptoms were also found in fields within Samcheok City and Yangku County of Korea during the 2011 and 2012 seasons. Disease incidence (percentage of plants affected) was 5 to 10% in organic farms surveyed. Diseased voucher specimens (n = 5) were deposited at the Korea University Herbarium (KUS). The disease first appeared as yellowish specks on leaves, expanding to cause a leaf tip dieback. Half of the leaves may be diseased within a week, especially during wet weather. Pycnidia were directly observed in leaf lesions. Pycnidia were amphigenous, but mostly epigenous, scattered, dark brown to rusty brown, globose, embedded in host tissue or partly erumpent, separate, unilocular, 50 to 150 μm in diameter, with ostioles of 20 to 40 μm in diameter. Conidia were acicular, straight to sub-straight, truncate at the base, obtuse at the apex, hyaline, aguttulate, 22 to 44 × 1.8 to 3 μm, mostly 3-septate, occasionally 1- or 2-septate. These morphological characteristics matched those of Septoria allii Moesz, which is differentiated from S. alliacea on conidial dimensions (50 to 60 μm long) (1,2). A monoconidial isolate was cultured on potato dextrose agar (PDA). Two isolates have been deposited in the Korean Agricultural Culture Collection (Accession Nos. KACC46119 and 46688). Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1/ITS4 primers and sequenced. The resulting sequence of 482-bp was deposited in GenBank (JX531648 and JX531649). ITS sequence information was at least 99% similar to those of many Septoria species, however no information was available for S. allii. Pathogenicity was tested by spraying leaves of three potted young plants with a conidial suspension (2 × 105 conidia/ml), which was harvested from a 4-week-old culture on PDA. Control leaves were sprayed with sterile water. The plants were placed in humid chambers (relative humidity 100%) for the first 48 h. After 7 days, typical leaf blight symptoms started to develop on the leaves of inoculated plants. S. allii was reisolated from the lesions of inoculated plants, confirming Koch's postulates. No symptoms were observed on control plants. The host-parasite association of A. tuberosum and S. allii has been known only from China (1). S. alliacea has been recorded on several species of Allium, e.g. A. cepa, A. chinense, A. fistulosum, and A. tuberosum from Japan (4) and A. cepa from Korea (3). To the best of our knowledge, this is the first report of S. allii on garlic chives. No diseased plants were observed in commercial fields of garlic chives which involved regular application of fungicides. The disease therefore seems to be limited to organic garlic chive production. References: (1) P. K. Chi et al. Fungous Diseases on Cultivated Plants of Jilin Province, Science Press, Beijing, China, 1966. (2) P. A. Saccardo. Sylloge Fungorum Omnium Hucusque Congnitorum. XXV. Berlin, 1931. (3) The Korean Society of Plant Pathology. List of Plant Diseases in Korea, Suwon, Korea, 2009. (4) The Phytopathological Society of Japan. Common Names of Plant Diseases in Japan, Tokyo, Japan, 2000.

Plant disease detection by hyperspectral imaging: from the lab to the field

2017 ◽  
Vol 8 (2) ◽  
pp. 238-243 ◽  
Author(s):  
A-K. Mahlein ◽  
M. T. Kuska ◽  
S. Thomas ◽  
D. Bohnenkamp ◽  
E. Alisaac ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Crop Production ◽  
Disease Incidence ◽  
Resistance Mechanism ◽  
Accurate Estimate ◽  
Plant Diseases ◽  
Negative Effects ◽  
Detection And Identification ◽  
Measuring Scale ◽  
Yield Quality

The detection and identification of plant diseases is a fundamental task in sustainable crop production. An accurate estimate of disease incidence, disease severity and negative effects on yield quality and quantity is important for precision crop production, horticulture, plant breeding or fungicide screening as well as in basic and applied plant research. Particularly hyperspectral imaging of diseased plants offers insight into processes during pathogenesis. By hyperspectral imaging and subsequent data analysis routines, it was possible to realize an early detection, identification and quantification of different relevant plant diseases. Depending on the measuring scale, even subtle processes of defence and resistance mechanism of plants could be evaluated. Within this scope, recent results from studies in barley, wheat and sugar beet and their relevant foliar diseases will be presented.

scholarly journals Factors affecting the distribution and abundance of the Endangered volcano rabbit Romerolagus diazi on the Iztaccihuatl volcano, Mexico

Oryx ◽  
2014 ◽  
Vol 49 (2) ◽  
pp. 366-375 ◽  
Author(s):  
Michael Hunter ◽  
Will Cresswell
Keyword(s):  
Habitat Type ◽  
Grazing Intensity ◽  
Cattle Grazing ◽  
Faecal Pellet ◽  
Conservation Priorities ◽  
Lower Altitude ◽  
Factors Affecting ◽  
Closed Forest ◽  
Pellet Counts ◽  
Strict Enforcement

AbstractThe volcano rabbit Romerolagus diazi is an Endangered species endemic to Mexico, with a range of < 400 km2. We investigated threats from destruction, fragmentation and degradation of habitat, hunting, and cattle grazing intensity in relation to the distribution and abundance of the volcano rabbit on the Iztaccihuatl volcano. Faecal pellet counts were taken as a proxy for rabbit abundance in 1,718 random 0.2 m2 quadrats at 859 sampling points along 25 transects, covering an area of c. 100 km2 at altitudes of 3,400–4,000 m. Presence of the species was significantly associated with absence of closed forest, absence of long grass types (not bunchgrass), shallow inclines, absence of cattle grazing, lower altitude, low hunting pressure (measured by proximity to ranger station), absence of bare ground and, contrary to previous findings, increased frequency of fire. The species was significantly more abundant in habitats with a greater percentage cover of zacaton (bunchgrass) and short grass types. It was significantly less abundant in areas with more hunting (measured by proximity to ranger station) and cattle grazing. Key conservation priorities are therefore the protection of the subalpine zacaton bunchgrass-dominated habitat type, strict enforcement of hunting laws and the removal of livestock from relevant national park boundary areas. However, the results suggest that frequent fires have a significant positive effect on the occurrence of the volcano rabbit as a result of habitat improvement and this is often a consequence of anthropogenic management of land for cattle grazing.

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