scholarly journals SEVERITY AND INTENSITY OF FUNGAL DISEASES OF CUCURBIT CROPS OF HAMIRPUR REGION, HP, INDIA

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Manu Vineet Sharma ◽  
Hem Chander
Keyword(s):  
Cucumis Sativus ◽  
Disease Severity ◽  
Leaf Spot ◽  
Fungal Pathogens ◽  
Disease Incidence ◽  
Fungal Diseases ◽  
Lagenaria Siceraria ◽  
Coccinia Grandis ◽  
Downy Mildews ◽  
Powdery Mildews

Cucurbitaceae is the vegetable family enriched with numerous vitamins and minerals. In early rainy season cucurbits are the host of different fungal pathogens. In present study, four fungal diseases dominant on three members of cucurbitaceae family are observed in Bhoranj block of District Hamirpur, lie in lower foot hills of Himachal Pradesh. Four fungal diseases along with host plants are leaf spot of Lagenaria siceraria, downy mildews of Cucumis sativus, powdery mildews of Coccinia grandis and powdery mildews of Cucumis sativus. Among all these diseases, Disease Incidence and Disease Severity of Powdery mildews of Coccinia grandis are most dominant i.e. 40.3±1 and 51.2±1 respectively. Disease Incidence and Disease Severity of Leaf spot of Lagenaria siceraria is least i.e. 12.5±1 and 1.1±1, respectively.

scholarly journals Strobilurins: New group of fungicides

2021 ◽  
Vol 5 (2) ◽  
pp. 063-064
Author(s):  
Selim Rasha E ◽  
Khalil Mohamed S
Keyword(s):  
Fungal Pathogens ◽  
Fungal Diseases ◽  
Complex Iii ◽  
Forest Trees ◽  
Tree Nuts ◽  
Field Crops ◽  
Downy Mildews ◽  
Powdery Mildews ◽  
Group Control ◽  
Basidiomycete Fungus

Strobilurin is a group of natural products and their synthetic analogs have been widely used to control and prevent fungal diseases. Strobilurins were firstly isolated in 1977 from the mycelium of Strobilurus tenacellus, a saprobic Basidiomycete fungus causing wood-rotting on forest trees. This group of pesticides was designed to manage fungal pathogens classes such as Ascomycetes, Basidiomycetes, and Oomycetes. Also, Strobilurin commercialized included derivatives such as are azoxystrobin, kresoxim-methyl, picoxystrobin, fluoxastrobin, oryzastrobin, dimoxystrobin, pyraclostrobin and trifloxystrobin. This group is a part of the larger group of QoI inhibitors, which act to inhibit the respiratory chain at the level of Complex III. Strobilurins group control an unusually wide array of fungal diseases, included water molds, downy mildews, powdery mildews, leaf spotting and rusts. This group are used on cereals, field crops, fruits, tree nuts, vegetables, turfgrasses and ornamentals. Also, Strobilurins found to enhance the plant growth in some cases.

scholarly journals The emergence of cereal fungal diseases and the incidence of leaf spot diseases in Finland

2008 ◽  
Vol 20 (1) ◽  
pp. 62 ◽  
Author(s):  
M. JALLI ◽  
P. LAITINEN ◽  
S. LATVALA
Keyword(s):  
Spring Wheat ◽  
Leaf Spot ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Field Survey ◽  
Fungal Diseases ◽  
Cochliobolus Sativus ◽  
Pyrenophora Tritici Repentis ◽  
Fungal Plant Pathogens ◽  
First Time

Fungal plant pathogens causing cereal diseases in Finland have been studied by a literature survey, and a field survey of cereal leaf spot diseases conducted in 2009. Fifty-seven cereal fungal diseases have been identified in Finland. The first available references on different cereal fungal pathogens were published in 1868 and the most recent reports are on the emergence of Ramularia collo-cygni and Fusarium langsethiae in 2001. The incidence of cereal leaf spot diseases has increased during the last 40 years. Based on the field survey done in 2009 in Finland, Pyrenophora teres was present in 86%, Cochliobolus sativus in 90% and Rhynchosporium secalis in 52% of the investigated barley fields. Mycosphaerella graminicola was identified for the first time in Finnish spring wheat fields, being present in 6% of the studied fields. Stagonospora nodorum was present in 98% and Pyrenophora tritici-repentis in 94% of spring wheat fields. Oat fields had the fewest fungal diseases. Pyrenophora chaetomioides was present in 63% and Cochliobolus sativus in 25% of the oat fields studied.;

Survey on pomegranate anthracnose caused by Colletotrichum Gloeosporioides (Penz.) In Marathwada region

2017 ◽  
Author(s):  
Chavan A. A. ◽  
Dhutraj D. N.
Keyword(s):  
Disease Severity ◽  
Colletotrichum Gloeosporioides ◽  
Disease Incidence ◽  
Punica Granatum ◽  
Fungal Diseases ◽  
Point Scale ◽  
Disease Survey ◽  
Cropping Seasons ◽  
Cent Disease ◽  
Important Disease

Among fungal diseases anthracnose caused by Colleotrichum gloeosporioides is the most important disease. Survey of pomegranate (Punica granatum) orchards was conducted during 2013-14 in all the cropping seasons viz. mrig bahar, Hastabar and ambia bahar to assess the incidence and severity of anthracnose on pomegranate in Aurangabad, Jalna, Beed Osmanabad, Latur, Nanded, Hingoli and Parbhaani district of Marathwada region of Maharashtra state. The per cent disease incidence (PDI) and disease severity were recorded using 0-5 point scale. The maximum PDI on leaf was recorded in Hingoli (24.04%) followed by Nanded (22.62%) and Parbhani (22.22%) while least PDI recorded in Aurangabaad (15.09%). On fruit maximum PDI recorded in Parbhani (28.80%) which least in Beed district (19.02%). The 9.83 per cent disease variety on leaf was observed in Hingoli district and 10.70 per cent on fruit in Parbhani district. The maximum PDI (27.44%) on fruit and disease severity 12.45 per cent on fruit was recorded in Arakata. The maximum mean PDI 21.30 per cent on leaf and 25.85 per cent on fruit was recorded on trees aged above 5 years. The highest per cent disease incidence 25.34 per cent on leaf and 26.78 per cent on fruit was recorded on mrig bahar and the highest disease severity of leaf 10.05 per cent and fruit 11.22 per cent was reocrded in mrig bahar.

First Report of Macrophomina phaseolina, Fusarium brachygibbosum, and Lasiodiplodia theobromae Causing Fungal Watermelon Vine Decline in Southwest and West-Central Florida

2021 ◽  
Author(s):  
Cristina Pisani ◽  
Scott Adkins ◽  
William W Turechek ◽  
Pragna C Patel ◽  
Erin Rosskopf
Keyword(s):  
Disease Severity ◽  
Fungal Pathogens ◽  
Disease Incidence ◽  
Macrophomina Phaseolina ◽  
Lasiodiplodia Theobromae ◽  
First Report ◽  
Central Florida ◽  
Untreated Check ◽  
Vine Decline ◽  
Yellowing Virus

Wilt and vine decline symptoms were observed on watermelon plants in Glades and Hardee Counties in Florida in spring 2017 that resembled viral watermelon vine decline caused by squash vein yellowing virus (SqVYV). When no SqVYV was detected, greenhouse studies and morphological and molecular analyses revealed three fungal pathogens, Macrophomina phaseolina, Fusarium brachygibbosum, and Lasiodiplodia theobromae, that were not previously reported on watermelon in Florida. A previously reported oomycete, Pythium spinosum, was also detected in some, but not all isolates, and but when applied independently, resulted in disease incidence that was comparable to the untreated check, ruling it out as a primary causal agent of the symptoms observed in the field. In one of three experiments, seedlings inoculated with a combination of Macrophomina phaseolina, Fusarium brachygibbosum, and Pythium spinosum suffered the highest disease severity based on AUDPC values. In another experiment, seedlings inoculated with F. brachygibbosum exhibited the most severe symptoms and rapid disease development following inoculation. When seeds were inoculated with either a single or a combination of the isolated fungi, those inoculated with L. theobromae resulted in seedlings with the greatest disease severity. This is the first report of these three fungal pathogens on watermelon in Florida.

scholarly journals Determining the Sources of Primary and Secondary Inoculum and Seasonal Inoculum Dynamics of Fungal Pathogens Causing Fruit Rot of Deciduous Holly

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 951-958
Author(s):  
Shan Lin ◽  
Francesca Peduto Hand
Keyword(s):  
Leaf Spot ◽  
Fungal Pathogens ◽  
Disease Incidence ◽  
Fruit Rot ◽  
Plant Production ◽  
Mature Fruit ◽  
Average Temperature ◽  
Leaf Spots ◽  
Maximum Minimum

Fruit rot of deciduous holly, caused by species of the genera Alternaria, Colletotrichum, Diaporthe, and Epicoccum, is affecting plant production in Midwestern and Eastern U.S. nurseries. To determine the sources of inoculum, dormant twigs and mummified fruit were collected, and leaf spot development was monitored throughout the season from three Ohio nurseries over two consecutive years. Mummified fruit was the main source of primary inoculum for species of Alternaria and Epicoccum, whereas mummified fruit and bark were equally important for species of Colletotrichum and Diaporthe. Brown, irregular leaf spots developed in the summer, and disease incidence and severity increased along with leaf and fruit development. Coalesced leaf spots eventually resulted in early plant defoliation. When tested for their pathogenicity on fruit, leaf spot isolates were able to infect wounded mature fruit and induce rot symptoms, which indicated that leaf spots could serve as a source of secondary inoculum for fruit infections. In addition, spore traps were used to monitor seasonal inoculum abundance in the nurseries. Fruit rot pathogens were captured by the spore traps throughout the season, with peak dissemination occurring during flowering. In this study, we also attempted to understand the role of environmental factors on leaf spot development. Although leaf spot incidence and severity were negatively correlated to mean maximum, minimum and average temperature, a decrease in temperature also coincided with leaf senescence. The role of temperature on leaf spot development should be further studied to fully interpret these results.

scholarly journals Temporal Progress of Septoria Leaf Spot on Rabbiteye Blueberry (Vaccinium ashei)

Plant Disease ◽  
2005 ◽  
Vol 89 (10) ◽  
pp. 1090-1096 ◽  
Author(s):  
P. S. Ojiambo ◽  
H. Scherm
Keyword(s):  
Disease Severity ◽  
Leaf Spot ◽  
Developmental Stages ◽  
Disease Incidence ◽  
Disease Onset ◽  
Parameter Estimates ◽  
Vaccinium Ashei ◽  
Leaf Emergence ◽  
Temporal Progress ◽  
Septoria Leaf Spot

Septoria leaf spot, caused by Septoria albopunctata, is an important disease on blueberry in the southeastern United States, yet its epidemiology is largely unknown. Disease severity and dissemination of pycnidiospores were monitored from 2002 to 2004 in a planting of susceptible Premier rabbiteye blueberry to characterize the temporal progress of the disease and determine the effect of inoculum dynamics and selected leaf attributes on disease development. Disease onset was observed between late April and mid-June, followed by a rapid increase in disease severity until mid- to late September; thereafter, disease severity decreased until the end of the season due to abscission of severely infected leaves. A logistic model was fitted to disease severity data using nonlinear regression, and parameter estimates were used to compare the effects of leaf position on the shoot and shoot location in the canopy on disease progress. Based on this model, the highest absolute rate of disease increase and the highest upper asymptote of disease severity were predicted for leaves in intermediate positions on the shoot and for shoots in the lower canopy. Data collected with funnel spore samplers showed that splash-dispersed pycnidiospores of S. albopunctata were available throughout most of the period from April through late October. Final disease severity on individual leaves was more strongly correlated with cumulative spore numbers throughout the entire season (from leaf emergence to the end of the assessment period in November) than with cumulative spore numbers during shorter periods around the time of leaf emergence; this suggests that infection is not limited to young, expanding leaves, but rather that leaves at all developmental stages can become infected by S. albopunctata seasonlong. Disease incidence on leaves of potted trap plants exposed to natural inoculum in the field during rain events in 2003 and 2004 was >70.0% irrespective of leaf developmental stage at the time of exposure. Taken together, the results of this study indicate that inoculum of S. albopunctata is present throughout most of the growing season and that infection can occur season-long on leaves of any age, giving rise to a polycyclic epidemic.

scholarly journals Incidence of two leaf fungal diseases in two plum training systems

2018 ◽  
Vol 24 (3-4) ◽  
Author(s):  
B. Molnár ◽  
M. Varga ◽  
A. Vámos ◽  
I. J. Holb
Keyword(s):  
Fungal Pathogens ◽  
Disease Incidence ◽  
Weather Conditions ◽  
Fungal Diseases ◽  
Susceptible Cultivar ◽  
Training Systems ◽  
Leaf Disease ◽  
Significant Difference

In a two-year study, we aimed to determine the susceptibility of four plum cultivars to two fungal pathogens of plum (Stigmina carpophila and Polystigma rubrum) in two training systems with tree spacings of 4 x 1.5m and 6 x 3m. Results showed that shothole symptoms were not detected on cvs ’Bluefre’ and ’Stanley’ in August, 2016. Disease incidence was above 50% in the case of ’Čačanska lepotica’ in both training systems in 2016. There were no significant difference between the two training systems. Shot hole incidence was lower in the 6 x 3m spacings compared to the 4 x 1.5m spacings on cv ’President’ in 2016. Cultivar ’Čačanska lepotica’ showed the highest incidence of Stigmina carpophila in the 4 x 1.5m spacing in 2017. Disease incidence of Stigmina carpophila was significantly lower in the 6 x 3m spacing compared to the 4 x 1.5m spacing. Shothole incidences on cv ’President’ were similar to the values in 2016 ranging from 40% to 60%. Leaf disease incidence was higher in the 4 x 1.5m spacing compared to the 6 x 3m plot. Low disease incidence (below 10%) was observed on cv ’Stanley’ in 2017 and only in the 4 x 1.5m spacing. There were no visible symptoms of blackhorn dotty in 2016 due to inadequate weather conditions for the Polystigma rubrum fungus. However, all the four cultivars were infected by Polystigma rubrum in 2017. The most susceptible cultivar was cv ’Čačanska lepotica’ with the highest disease incidence in the 4 x 1.5m spacing. Disease incidence of this cultivar was lower in the 6 x 3m spacing which was significantly less than in the 4 x 1.5m spacing. The least susceptible cultivar was ’Bluefre’ and symptoms were observed only in the spacing of 4 x 1.5m. The disease incidence of cv ’President’ was similarly low to cv ’Stanley’ in both spacings.

scholarly journals Silicon-Induced Systemic Defense Responses in Perennial Ryegrass Against Infection by Magnaporthe oryzae

2015 ◽  
Vol 105 (6) ◽  
pp. 748-757 ◽  
Author(s):  
Alamgir Rahman ◽  
Christopher M. Wallis ◽  
Wakar Uddin
Keyword(s):  
Disease Management ◽  
Perennial Ryegrass ◽  
Magnaporthe Oryzae ◽  
Leaf Spot ◽  
Calcium Silicate ◽  
Fungal Pathogens ◽  
Disease Incidence ◽  
Defense Responses ◽  
Gray Leaf Spot ◽  
Integrated Disease Management

Sustainable integrated disease management for gray leaf spot of perennial ryegrass may involve use of plant defense elicitors with compatible traditional fungicides to reduce disease incidence and severity. Silicon (Si) has previously been identified as a potential inducer or modulator of plant defenses against different fungal pathogens. To this end, perennial ryegrass was inoculated with the causal agent of gray leaf spot, Magnaporthe oryzae, when grown in soil that was nonamended or amended with three different levels of calcium silicate (1, 5, or 10 metric tons [t]/ha). When applied at a rate of 5 t/ha, calcium silicate was found to significantly suppress gray leaf spot in perennial ryegrass, including a significant reduction of disease incidence (39.5%) and disease severity (47.3%). Additional studies observed nonpenetrated papillae or cell-wall appositions harboring callose, phenolic autofluorogens, and lignin-associated polyphenolic compounds in grass grown in the Si-amended soil. Regarding defense-associated enzyme levels, only following infection did grass grown in Si-amended soil exhibit greater activities of peroxidase and polyphenol oxidase than equivalent inoculated control plants. Also following infection with M. oryzae, grass levels of several phenolic acids, including chlorogenic acid and flavonoids, and relative expression levels of genes encoding phenylalanine ammonia lyase (PALa and PALb) and lipoxygenase (LOXa) significantly increased in Si-amended plants compared with that of nonamended control plants. These results suggest that Si-mediated increase of host defense responses to fungal pathogens in perennial ryegrass has a great potential to be part of an effective integrated disease management strategy against gray leaf spot development.

scholarly journals Planting Technique Matters in Reducing Vinca Disease in Landscapes

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1004D-1004
Author(s):  
Yan Chen ◽  
Regina Bracy ◽  
Allen Owings
Keyword(s):  
Plant Growth ◽  
Disease Severity ◽  
Leaf Spot ◽  
Sandy Loam ◽  
Disease Incidence ◽  
Growth Index ◽  
Fertilization Rate ◽  
Negative Effects ◽  
Alternaria Leaf Spot ◽  
Quality Ratings

Annual vinca, Catharanthus roseus, is exceptionally adaptive to the summer heat and the sandy loam or clay soil in the southeastern region and provides season-long blooms once established in landscape plantings. A wide variety of colors, sizes, and applications are available for landscape use. However, diseases such as alternaria leaf spot and phytophthora leaf blight are prevalent in this region in vinca plantings. Effective disease control requires frequent fungicide application that is expensive and may pose negative effects on the environment. Proper planting techniques including date of planting, fertilization rate at planting, and variety selection may improve plant growth, reduce disease severity, and save landscape service business labor in disease management. Plants of three varieties: open-pollinated `Cooler Hot Rose', F1 hybrid `Titan Rose', and trailing variety `Mediterranean Lilac' were planted on 1 Apr. or 1 May in landscape plots. Plants were at the same growth stage at the time of planting and were fertilized with Osmocote 14–14–14 (3 months) at 0, 35, 70, or 140 g·m2. Plant growth index indicates that plant growth increased significantly at increasing fertilization rates; however, plant overall quality ratings were not significantly different among fertilized plants. Disease incidence in July suggests that late planting may reduce alternaria leaf spot in open-pollinated and hybrid upright type vinca. Disease severity in August was more pronounced on trailing vinca and more severe when plants were not fertilized or fertilized with the highest fertilization rate. Tissue analysis indicates that trailing vinca `Mediterranean Lilac' may require less fertilization than upright type.

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