Epidemiological studies on the anthracnose diseases of Stylosanthes spp. caused by Colletotrichum gloeosporioides in North Queensland and pathogenic specialization within the natural fungal populations

Field experiments were conducted during three wet seasons (1982-84) on two sites in north Queensland to examine the natural occurrence of anthracnose caused by Collectotrichum gloeosporioides on six Stylosanthes spp. The disease incidence varied from moderate to high in a number of accessions, while others showed good field resistance for the duration of the experiment. Anthracnose severity was similar at both sites, although total rainfall each season was c. four times higher at one site than at the other. In some cases disease severity was higher at the drier site. It was difficult to determine a relationship between the environmental parameters measured (rainfall, temperature and relative humidity) and disease incidence and severity. Disease severity patterns varied between accessions at the same site, indicating a response to a factor or factors not associated with the measured weather parameters. There were seven pathogenicity groups, based on host specificities in glasshouse studies, identified within the Type A fungal population and a further seven groups within the Type B population. This indicates an increase in the number of fungal groups reported in Australia, and suggests that a stepwise increase in specificity may be occurring within the fungal population.

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Resistance of standing milkvetch (Astragalus adsurgens) varieties to Embellisia astragali

Crop and Pasture Science ◽

10.1071/cp12107 ◽

2012 ◽

Vol 63 (4) ◽

pp. 351 ◽

Cited By ~ 2

Author(s):

B. H. Yu ◽

Z. B. Nan ◽

Y. Z. Li ◽

H. L. Lin

Keyword(s):

Disease Severity ◽

Field Experiments ◽

Agronomic Traits ◽

Disease Incidence ◽

Dry Weight ◽

Severity Index ◽

Field Conditions ◽

Disease Severity Index ◽

Greenhouse Experiments ◽

Astragalus Adsurgens

Yellow stunt and root rot caused by Embellisia astragali are major factors contributing to declining yields of standing milkvetch (Astragalus adsurgens). The resistance of ten varieties of standing milkvetch to E. astragali was evaluated under laboratory, greenhouse, and field conditions. Seed germination/emergence, shoot and root length, plant dry weight, disease incidence, mortality, and disease severity index were monitored. The results show that Shanxi and Zhongsha No. 1 varieties had the best agronomic traits and lowest levels of disease in all experiments, while the varieties Neimeng and Ningxia had the highest susceptibility to disease. Germination/emergence differed significantly (P < 0.05) between varieties after inoculation, and compared with the control, germination/emergence of inoculated treatments of nine varieties decreased on average by 1.5% in laboratory experiments and by 4.1% in greenhouse experiments at 15 days after inoculation. Inoculation reduced shoot length by an average of 24.4% and 41.5% (P < 0.05) in laboratory and greenhouse experiments, respectively, in six of ten varieties. All varieties showed significantly (P < 0.05) lower plant dry weight following inoculation, with reductions ranging from 0.3 to 0.6 mg in the laboratory and from 82.6 to 149.4 mg in the greenhouse. Resistance to the pathogen was evaluated on the basis of disease incidence, a disease severity index (DSI), and mortality; varieties showing different resistance were grouped using cluster analysis. There were significant correlations between the results of laboratory and greenhouse experiments (r = 0.79; P < 0.01) and between greenhouse and field experiments (r = 0.83; P < 0.01) across all varieties. Multiple regression analysis between laboratory/greenhouse and field experiments on DSI suggested that screening in the laboratory/greenhouse could be an alternative method of rapidly estimating DSI under field conditions.

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Effect of Traditional Agronomic Practices on White Rust of Rapeseed – Mustard under Organic Farming System in Manipur

Current Agriculture Research Journal ◽

10.12944/carj.5.3.14 ◽

2017 ◽

Vol 5 (3) ◽

pp. 354-358

Author(s):

Yengkhom Premlata Devi

Keyword(s):

Disease Severity ◽

Field Experiments ◽

Plant Density ◽

Disease Incidence ◽

Farmyard Manure ◽

Farming System ◽

Severe Form ◽

Rust Disease ◽

White Rust ◽

Agronomic Practices

Rapeseed – mustard is one of the most important cruciferous oilseed crops basically raise for oils and vegetables to meet domestic consumption of marginal farmers during rabi season in Manipur. Field experiments were conducted under organic condition for two consecutive years ( 2014 & 2015) during rabi seasons at Kakching. Weekly surveys detected white rust of rapeseed –mustard on the four varieties used. Amendments of agronomic practices including sowing dates, intercropping and plant density besides addition of soil with FYM (Farmyard Manure) were found effective on fungal disease of the crop. The disease parameters were monitored through disease incidence (DI) and disease severity (DS) assessment technique. The least disease severity (9.57%) was found in plant density followed by date of sowing (11.06%) and intercropping (12.29%). White rust caused by Albugo candida attacked the crop from mild to severe form and the effect of agronomic practices applied were significant in controlling the white rust disease of the crop.

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EFFECT OF BOTANICALS FOR MANAGEMENT OF LEAF BLAST AND ENHANCING YIELD TRAITS IN RICE

Current Botany ◽

10.25081/cb.2018.v9.3548 ◽

2018 ◽

pp. 17-21

Author(s):

SANDEEP PANDEY

Keyword(s):

Grain Yield ◽

Disease Severity ◽

Field Experiments ◽

Disease Incidence ◽

Grain Weight ◽

Panicle Length ◽

Leaf Blast ◽

Yield Attributes ◽

Pooled Data ◽

Cent Disease

Field experiments were undertaken during kharif 2012 and 2013 under irrigated ecosystem to evaluate the efficacy of botanicals along with standard fungicides for assessing per cent disease incidence, plant height, number of tiller per plant, number of spikelet per panicle, panicle length, 100-grain weight and grain yield against blast of rice. Pooled data of two years suggest that neem based commercial biopesticides with azadiractin as active ingredients were found effective in reducing disease severity and improving the yield attribute of the crop and proves promising products when compared to standard fungicides. Among the botanicals the spraying of Achook, Neem Azal T/S, Neem gold and Tricure shows significant reduction in disease severity, along with improving yield attributes, increasing the 100-grain weight and grain yield.

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Effect of weather parameters, host resistance and sowing date on disease severity and temporal dynamics of Fusarium wilt in chickpea (Cicer arietinum L.)

Journal of Agrometeorology ◽

10.54386/jam.v24i1.1028 ◽

2022 ◽

Vol 24 (1) ◽

Author(s):

ANNIE KHANNA ◽

KUSHAL RAJ ◽

PANKAJ KUMAR

Keyword(s):

Disease Severity ◽

Cicer Arietinum ◽

Fusarium Wilt ◽

Field Experiments ◽

Severity Index ◽

Susceptible Variety ◽

Resistant Variety ◽

Disease Severity Index ◽

Cicer Arietinum L ◽

Weather Parameters

Fusarium wilt incited by Fusarium oxysporum f. sp. ciceris is an economically damaging disease of chickpea (Cicer arietinum L.). Field experiments on epidemiological studies revealed that sowing during second fortnight of November curtailed the disease severity index (22.50 and 20.83% during 2018-19 and 2019-20, respectively) whereas, sowing during first fortnight of October enhanced the disease severity index (34.86 and 30.41%). The area under disease progress curve was significantly higher in susceptible variety JG 62 and was the least in resistant variety HC 1. The correlation analysis exhibited positive correlation of disease severity index with maximum and minimum temperature while negative correlation with relative humidity morning and evening, irrespective of date of sowing. The principal component analysis depicted resistance index, sowing time and weather parameters as positional factors in determining Fusarium wilt progression. In susceptible variety, Gompertz model was the best fitted model for simulating the Fusarium wilt epidemic over time.

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Phenology of Apothecium Production in Populations of Monilinia vaccinii-corymbosi from Early- and Late-Maturing Blueberry Cultivars

Phytopathology ◽

10.1094/phyto.1997.87.2.218 ◽

1997 ◽

Vol 87 (2) ◽

pp. 218-223 ◽

Cited By ~ 24

Author(s):

Jeffrey S. Lehman ◽

Peter V. Oudemans

Keyword(s):

Field Experiments ◽

Shoot Elongation ◽

Separate Experiment ◽

Controlled Experiments ◽

Fungal Population ◽

Development Times ◽

Host Phenology ◽

Fungal Populations ◽

Artificial Inoculations ◽

Average Development

Pseudosclerotia were evaluated for differences in timing of apothecium development in four controlled experiments conducted over a 2-year period. In a separate experiment, conidia from 10 randomly selected isolates from both of the fungal populations were used to inoculate open flowers. Germination of pseudosclerotia produced from these artificial inoculations also was evaluated. The timing and rate of shoot elongation for cvs. Weymouth and Jersey were assessed in one greenhouse and two field experiments. Average development times for the fungal population from cv. Weymouth were 8 to 15 days earlier or 33 to 42% less than those for the population from cv. Jersey. The fungal population from Weymouth also exhibited less variation in development times for each developmental stage measured. Similarly, germination of pseudosclerotia produced in artificial inoculations differed between populations. On average, pseudosclerotia derived from the Weymouth population produced apothecia 16 days earlier. During spring 1995 and 1996, vegetative and truss buds on cv. Weymouth developed 4 to 16 days earlier than those on cv. Jersey. These results demonstrate that M. vaccinii-corymbosi exhibits variation in timing of pseudosclerotia germination and apothecium development within and between populations. We hypothesize that differences observed in the timing of apothecium development are related to the fitness of the populations on their original host cultivars and were selected by host phenology.

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Effects of Chitin and Chitosan on the Incidence and Severity of Fusarium Yellows of Celery

Plant Disease ◽

10.1094/pdis.1998.82.3.322 ◽

1998 ◽

Vol 82 (3) ◽

pp. 322-328 ◽

Cited By ~ 79

Author(s):

Ashley A. Bell ◽

Judith C. Hubbard ◽

Li Liu ◽

R. Michael Davis ◽

Krishna V. Subbarao

Keyword(s):

Fusarium Oxysporum ◽

Disease Severity ◽

Field Experiments ◽

Disease Incidence ◽

Soil Microflora ◽

Biocontrol Agents ◽

Standard Soil ◽

History Of ◽

Chitin And Chitosan ◽

Soil Dilution

The effects of chitin and chitosan on disease incidence and severity of Fusarium yellows of celery and on populations of Fusarium oxysporum were investigated between 1994 and 1996. Field experiments were conducted at two locations with a history of severe Fusarium yellows. Disease incidence and severity were significantly reduced by pre-plant chitin amendments to soil. Chitosan applied as a root dip alone did not reduce disease incidence but significantly (P < 0.05) reduced disease severity when used with a tolerant celery cultivar. Standard soil dilution methods were used to enumerate populations of soil microflora. Chitin increased bacterial and actinomycete populations in soil in 2 of the 3 years of study. The effects of potential biocontrol agents recovered from chitin-treated plots in 1995 were studied in 1996; enriching the transplant medium with isolates of bacteria and actinomycetes 4 weeks and 1 week prior to transplanting did not alter the established equilibrium in the field, and no biocontrol effect was observed. Chitin amendments to soil or chitosan treatment of transplants did not reduce soil populations of F. oxysporum. Whether these treatments affected the F. oxysporum f. sp. apii subpopulation within the F. oxysporum population could not be determined.

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Assessment of a water filtration device for household use in rural communities in Mexico

Water Science & Technology ◽

10.2166/wst.1997.0711 ◽

1997 ◽

Vol 35 (11-12) ◽

pp. 65-69 ◽

Cited By ~ 2

Author(s):

M. Galván ◽

J. de Victorica

Keyword(s):

Rural Communities ◽

Gastrointestinal Disease ◽

Disease Incidence ◽

Field Evaluation ◽

Epidemiological Studies ◽

Poor Quality ◽

Laboratory Conditions ◽

Operation Conditions ◽

Rural Mexico ◽

Quality Water

Epidemiological studies in rural Mexico have shown the role of poor quality water in gastrointestinal disease incidence. This led to the establishment of a program, which included the assessment of inexpensive systems for household treatment of drinking water. We describe the main features of a hand carved stone filter evaluated over 6 months under laboratory conditions and 6 months under household conditions. The filter had a capacity of 5L and an average volume of 18L/d filtered water (the temperature of which was always an average 4°C lower than the influent). Average bacterial removals under laboratory conditions were 98% for total and faecal coliforms (TC, FC), 96% for faecal streptococci (FS), 99% for Pseudomonas aeruginosa and 100% for helminth eggs and protozoan cysts. During the field evaluation removals were 80–100% TC, 45–95% FC and 8–93% FS due to the different qualities of influent water and the operation conditions. Nevertheless, the filters represented an immediate mitigation measure of the health risks associated with the continuous ingestion of microbiologically unsafe waters.

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EFFECT OF SEED DIFFUSATES ON FUNGAL POPULATION AND GERMINATION OF SUNFLOWER SEEDS / EFECTO DE EXTRACTOS DE SEMILLAS SOBRE LA POBLACION DE HONGOS Y LA GERMINACION DE SEMILLAS DEL GIRASOL / EFFET DES EXTRAITS DE SEMENCE SUR LA POPULATION DE CHAMPIGNONS ET SUR LA GERMINATION DES GRAINES DE TOURNESOL

Helia ◽

10.1515/helia.2001.24.34.77 ◽

2001 ◽

Vol 24 (34) ◽

pp. 77-82 ◽

Cited By ~ 1

Author(s):

Rauf Bhutta ◽

M.H. Rahber Bhatti ◽

Ahmad Iftikhar

Keyword(s):

Seed Germination ◽

Capsicum Annuum ◽

Alternaria Alternata ◽

Fusarium Moniliforme ◽

Macrophomina Phaseolina ◽

Chemical Pollution ◽

Sunflower Seeds ◽

Fungal Population ◽

Fungal Populations ◽

Safe Control

SUMMARYAll four seed diffusates used for treatment of sunflower seeds, Azadirachtaindica, Capsicum annuum, Coriandrum sativum and Eugenia jambulana, reduced the populations of seed-borne fungi: Alternaria alternata, Drechslera tetramera, Emericellopsis terricola, Fusarium moniliforme, F.semitectum, Macrophomina phaseolina and Phoma oleracea. Of four seed diffusates, those from A.indica and C.sativum controlled the fungal populations almost 100%. Seed germination was increased in seed samples of both sunflower cultivars under study, HO-1 and NK-212. The obtained results indicate that seed diffusates could substitute costly chemicals for safe control of seed-borne diseases, protecting at the same time the environment from chemical pollution.

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Field Evaluations of Leaf Spot Resistance and Yield in Peanut Genotypes in the United States and Bolivia

Plant Disease ◽

10.1094/pdis-06-10-0454 ◽

2011 ◽

Vol 95 (3) ◽

pp. 263-268 ◽

Cited By ~ 4

Author(s):

S. K. Gremillion ◽

A. K. Culbreath ◽

D. W. Gorbet ◽

B. G. Mullinix ◽

R. N. Pittman ◽

...

Keyword(s):

United States ◽

Disease Resistance ◽

Leaf Spot ◽

Field Experiments ◽

Disease Incidence ◽

The United States ◽

Yield Potential ◽

Cercospora Arachidicola ◽

Breeding Lines ◽

Progress Curve

Field experiments were conducted in 2002 to 2006 to characterize yield potential and disease resistance in the Bolivian landrace peanut (Arachis hypogaea) cv. Bayo Grande, and breeding lines developed from crosses of Bayo Grande and U.S. cv. Florida MDR-98. Diseases of interest included early leaf spot, caused by the fungus Cercospora arachidicola, and late leaf spot, caused by the fungus Cercosporidium personatum. Bayo Grande, MDR-98, and three breeding lines, along with U.S. cvs. C-99R and Georgia Green, were included in split-plot field experiments in six locations across the United States and Bolivia. Whole-plot treatments consisted of two tebuconazole applications and a nontreated control. Genotypes were the subplot treatments. Area under the disease progress curve (AUDPC) for percent defoliation due to leaf spot was lower for Bayo Grande and all breeding lines than for Georgia Green at all U.S. locations across years. AUDPC for disease incidence from one U.S. location indicated similar results. Severity of leaf spot epidemics and relative effects of the genotypes were less consistent in the Bolivian experiments. In Bolivia, there were no indications of greater levels of disease resistance in any of the breeding lines than in Bayo Grande. In the United States, yields of Bayo Grande and the breeding lines were greater than those of the other genotypes in 1 of 2 years. In Bolivia, low disease intensity resulted in the highest yields in Georgia Green, while high disease intensity resulted in comparable yields among the breeding lines, MDR-98, and C-99R. Leaf spot suppression by tebuconazole was greater in Bolivia than in the United States. This result indicates a possible higher level of fungicide resistance in the U.S. population of leaf spot pathogens. Overall, data from this study suggest that Bayo Grande and the breeding lines may be desirable germplasm for U.S. and Bolivian breeding programs or production.

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Effect of Compost Amendments on Disease Severity and Yield of Tomato in Conventional and Organic Production Systems

Plant Disease ◽

10.1094/pdis.2002.86.2.156 ◽

2002 ◽

Vol 86 (2) ◽

pp. 156-161 ◽

Cited By ~ 83

Author(s):

P. A. Abbasi ◽

J. Al-Dahmani ◽

F. Sahin ◽

H. A. J. Hoitink ◽

S. A. Miller

Keyword(s):

Disease Severity ◽

Production Systems ◽

Disease Incidence ◽

Organic Production ◽

Fruit Rot ◽

High Rate ◽

Bacterial Spot ◽

Marketable Yield ◽

Tomato Production ◽

Compost Amendments

Field trials were conducted over 2 years to assess the effects of compost amendments on disease development in organic and conventional processing tomato (Lycopersicon esculentum L.) production systems. The incidence of anthracnose fruit rot was reduced in organic tomato plots amended with a high rate of composted cannery wastes compared with the incidence in nonamended control plots in 1998 when disease incidence was high. Marketable yield was increased by 33% in compost-amended organic plots. Plots amended with a high compost rate had more ripe fruit than the nonamended control. The incidence of anthracnose and of total disease on fruit was less on the cultivar OH 8245 than on Peto 696. Total fruit yield of OH 8245 but not Peto 696 in organic plots was increased by amendment with composted cannery wastes. In conventional tomato production, composted yard wastes increased disease severity on foliage both years but reduced bacterial spot incidence on fruit in 1997, when disease pressure was high. The incidence of anthracnose was not affected by composted yard wastes. Marketable and total fruit yields of Peto 696 were not increased in compost-amended conventional plots. The plant activator Actigard reduced foliar disease severity and the incidence of bacterial spot and anthracnose on fruit, while increasing yield of marketable fruit.

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