scholarly journals Horticultural Characteristics and Susceptibility of Table Beet Cultivars to Cercospora Leaf Spot in New York

2017 ◽  
Vol 27 (4) ◽  
pp. 530-538 ◽  
Author(s):  
Sarah J. Pethybridge ◽  
Niloofar Vaghefi ◽  
Julie R. Kikkert
Keyword(s):  
New York ◽  
Leaf Spot ◽  
Field Trial ◽  
Near Infrared ◽  
Value Added ◽  
Dry Weight ◽  
Disease Assessment ◽  
Canopy Reflectance ◽  
Cercospora Leaf Spot ◽  
Disease Progress

Table beet (Beta vulgaris ssp. vulgaris) production in New York is increasing for direct sale, use in value-added products, or processing. One of the most important diseases affecting table beet is cercospora leaf spot (CLS) caused by the fungus Cercospora beticola. CLS causes lesions on leaves that coalesce and leads to premature defoliation. The presence of CLS may cause buyer rejection at fresh markets. Defoliation from CLS may also result in crop loss because of the inability to harvest with top-pulling machinery. The susceptibility of popular table beet cultivars (Boldor, Detroit, Falcon, Merlin, Rhonda, Ruby Queen, and Touchstone Gold) to CLS was tested using C. beticola isolates representative of the New York population. Two trials were conducted by inoculating 6-week-old plants in the misting chamber. A small-plot replicated field trial was also conducted to examine horticultural characteristics of the cultivars. In the misting chamber trials, disease progress measured by the area under the disease progress stairs (AUDPS) was not significantly different between the red cultivars, Detroit and Ruby Queen, and was significantly higher in ‘Boldor’ than the other yellow cultivar Touchstone Gold. In the field trial, the number of CLS lesions per leaf at the final disease assessment and AUDPS were significantly lower in cultivar Ruby Queen than others and not significantly different between the yellow cultivars. The dry weight of roots was not significantly different among cultivars at first harvest (77 days after planting). At 112 days after planting, the dry weight of roots was significantly higher in cultivar Detroit than Rhonda and Boldor. Leaf blade length and the length:width ratio were cultivar-dependent, which may facilitate selection for specific fresh markets. Significant associations between canopy reflectance in the near infrared (IR) (830 nm), dry weight of foliage, and number of CLS lesions per leaf suggested that this technique may have utility for remote assessment of these variables in table beet research. Implications of these findings for the management of CLS in table beet are discussed.

scholarly journals Management of Cercospora Leaf Spot in Conventional and Organic Table Beet Production

Plant Disease ◽  
2017 ◽  
Vol 101 (9) ◽  
pp. 1642-1651 ◽  
Author(s):  
Sarah J. Pethybridge ◽  
Niloofar Vaghefi ◽  
Julie R. Kikkert
Keyword(s):  
New York ◽  
Disease Control ◽  
Leaf Spot ◽  
Production Systems ◽  
Dry Weight ◽  
Field Trials ◽  
Cercospora Leaf Spot ◽  
Disease Progress ◽  
Shoulder Diameter ◽  
Small Plot

Cercospora leaf spot (CLS; Cercospora beticola) is the most important foliar disease affecting table beet. Epidemics occur annually and fungicides extend the survival of foliage to enable mechanized harvest. However, a high frequency of strobilurin-resistant C. beticola isolates necessitates the identification of fungicides with different modes of action for tactical rotation. There is also substantial demand for organically produced table beet, for which synthetic fungicides are prohibited. Five small-plot, replicated field trials were conducted over two years to evaluate conventional and Organic Materials Review Institute (OMRI)-listed products for CLS control in table beet cv. Ruby Queen at Geneva and Ithaca, New York. Benzovindiflupyr + difenoconazole significantly reduced temporal disease progress (measured by the area under the disease progress stairs; AUDPS) by 86.7 to 97.3% compared with nontreated plots, and mean survival time of leaves was significantly extended. The demethylation inhibitor, propiconazole, also provided significant disease control in two trials in 2016. Disease severity in plots treated with succinate dehydrogenase inhibitors (boscalid, fluxapyroxad + pyraclostrobin, and penthiopyrad) was significantly decreased compared with nontreated plots but less than other fungicides. Efficacious fungicides significantly increased the dry weight of foliage but did not significantly affect the dry weight of roots, and root shoulder diameter. The enhanced longevity of leaves and increased dry weight of foliage may extend opportunities for mechanized harvesting without deleteriously affecting root yield parameters which are strictly regulated for the processing markets. In two trials, copper octanoate + Bacillus amyloliquefaciens strain D747 (as Cueva + Double Nickel LC) resulted in significantly improved disease control in comparison with application of either product alone and provided comparable and reproducible disease control equivalent to conventional fungicides at both locations. The implications of these findings for CLS control in conventional and organic table beet production systems are discussed.

scholarly journals Effect of Production System and Pruning on Temporal Development of Cercospora depazeoides and on Berry Yield in Black Elderberry Orchards

Plant Disease ◽  
2009 ◽  
Vol 93 (6) ◽  
pp. 625-631 ◽  
Author(s):  
I. J. Holb ◽  
J. M. Gáll ◽  
B. Fodor
Keyword(s):  
Leaf Spot ◽  
Production Systems ◽  
Disease Incidence ◽  
Organic Production ◽  
Integrated System ◽  
Disease Development ◽  
Temporal Development ◽  
Cercospora Leaf Spot ◽  
Organic System ◽  
Disease Progress

In a 2-year study, the temporal development of Cercospora leaf spot (Cercospora depazeoides) and berry yield were evaluated in two production systems (integrated and organic) and in two winter pruning treatments (trees pruned to four and eight scaffolds) in two black elderberry (Sambucus nigra) orchards in Hungary. Under organic production, leaf spot onset occurred 2 to 4 weeks earlier (mid- and late July) in both years and both orchards compared with the integrated program. Disease then continuously progressed until the final assessment date (late September) in both years, reaching a maximum final disease incidence of 15.9% in the integrated system and of 38.2% in the organic system. In general, disease progress after late August was greater on trees pruned to eight scaffolds than on trees pruned to four scaffolds in both production systems. Both final disease incidence and area under the disease progress curves (AUDPC) were significantly lower (P < 0.001) in the integrated treatments compared with organic ones. Across all treatments, both disease measures were significantly (P < 0.05) lower on trees pruned to four scaffolds compared with trees pruned to eight scaffolds. However, when the effect of pruning on final disease incidence and AUDPC was analyzed separately for integrated and organic systems, pruning caused uniformly significant differences in disease development only for the organic system. Berry yield was significantly higher (P < 0.05) in the integrated system compared with the organic system, but pruning showed no significant effect on yield. Overall, pruning to four scaffolds resulted in consistently lower disease development in organic production compared to integrated. Thus, winter pruning may be useful as a Cercospora leaf spot management practice in organic elderberry orchards.

Development of a Sequential Sampling Plan using Spatial Attributes of Cercospora Leaf Spot Epidemics of Table Beet in New York

Plant Disease ◽  
2021 ◽  
Author(s):  
Daniel Winter Heck ◽  
Julie R Kikkert ◽  
Linda Hanson ◽  
Sarah Jane Pethybridge
Keyword(s):  
New York ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Sequential Sampling ◽  
Sampling Plan ◽  
Classification Models ◽  
Cercospora Leaf Spot ◽  
Sample Number ◽  
Sequential Sampling Plan ◽  
True Value

Sampling strategies that effectively assess disease intensity in the field are important to underpin management decisions. To develop a sequential sampling plan for the incidence of Cercospora leaf spot (CLS), caused by Cercospora beticola, 31 table beet fields were assessed in New York. Assessments of CLS incidence were performed in six leaves arbitrarily selected in 51 sampling locations along each of the three to six linear transects per field. Spatial pattern analyses were performed, and results were used to develop sequential sampling estimation and classification models. CLS incidence (p) ranged from 0.13 to 0.92 with a median of 0.31, and beta-binomial distribution, which is reflective of aggregation, best described the spatial patterns observed. Aggregation was commonly detected (>95%) by methods using the point-process approach, runs analyses, and autocorrelation up to the fourth spatial lag. For SADIE, 45% of the datasets were classified as a random pattern. In the sequential sampling estimation and classification models, disease units are sampled until a prespecified target is achieved. For estimation, the goal was sampling CLS incidence with a preselected coefficient of variation (C). Achieving the C = 0.1 was challenging with less than 51 sampling units, and only observed on datasets with an incidence above 0.3. Reducing the level of precision, i.e. increasing C to 0.2, allowed the preselected C be achieved with a lower number of sampling units and with an estimated incidence (p̂) close to the true value of p. For classification, the goal was to classify the datasets above or below prespecified thresholds (pt) used for CLS management. The average sample number (ASN) was determined by Monte Carlo simulations, and was between 20 and 45 at disease incidence values close to pt, and approximately 11 when far from pt. Correct decisions occurred in over 76% of the validation datasets. Results indicated these sequential sampling plans can be used to effectively assess CLS incidence in table beet fields.

scholarly journals Evaluation of an Aeroponics System to Screen Maize Genotypes for Resistance to Fusarium graminearum Seedling Blight

Plant Disease ◽  
1997 ◽  
Vol 81 (2) ◽  
pp. 175-179 ◽  
Author(s):  
Lindsey J. du Toit ◽  
H. Walker Kirby ◽  
Wayne L. Pedersen
Keyword(s):  
Fusarium Graminearum ◽  
Root Rot ◽  
Shoot Growth ◽  
Dry Weight ◽  
Rapid Screening ◽  
Disease Assessment ◽  
Seedling Blight ◽  
Disease Progress ◽  
Root Dry Weight ◽  
Maize Genotypes

A noncirculating aeroponics system was evaluated as a method for rapid screening of maize genotypes for resistance to Fusarium graminearum seedling blight/root rot. The system allows for nondestructive, repetitive sampling of seedlings for assessing disease progress and seedling growth. Shoot growth and root rot were assessed at 3-day intervals, and final shoot and root dry weight were determined 15 days after inoculation. The nine hybrids screened differed in severity of root rot as early as 6 days after inoculation, indicating differences in resistance to F. graminearum. Inoculation did not always significantly affect shoot growth, root dry weight, or shoot dry weight, but differences in these agronomic traits were observed among hybrids.LH119 × LH51 and Pioneer Brand 3379 showed the greatest resistance to root rot. Area under-disease progress curve and a critical stage of disease assessment (9 days after inoculation) gave similar rankings of hybrids for root rot resistance, indicating that a single disease assessment (versus multiple assessments) may be adequate in screening for resistance with this aeroponics system.

scholarly journals Enhancing Peanut Productivity through Application Of Irradiated κ- Carrageenan

2019 ◽  
Vol 8 (3) ◽  
pp. 6977-6981
Keyword(s):  
Seed Yield ◽  
Leaf Spot ◽  
Field Trial ◽  
Block Design ◽  
Statistical Design ◽  
Cercospora Leaf Spot ◽  
Pod Yield ◽  
Field Verification ◽  
Randomized Complete Block Design ◽  
Additional Income

On-field verification trials were conducted to determine the effect of various rates of Olio-carrageenan (PGP) on Cercospora leaf spot (CLS) and rust and yield of peanut varieties specifically, BPI Pn9 and Farmer’s variety. The statistical design of the field trial was a Randomized Complete Block Design (RCBD) with four replicates per treatment per experiment. The CLS and rust infections were significantly reduced with the application of 150ppm PGP by 15.2% and 36.2%, respectively. The BPI Pn 9 peanut variety applied with PGP consistently and significantly had higher pod yield up to 2.14 t/ha and seed yield of 1.63 t/ha with a corresponding 37.6% and 34.5% increase, respectively. At least Php45,771 per hectare additional income was realized from the application of PGP with a maximum MBCR of 12.3%. For Farmer’s peanut variety, significant increase of 23.6% on pod yield and 36.5% on seed yield were obtained resulting to an additional income of Php 18,400/ha up to 37,800/ha with an MBCR of 21.81%

scholarly journals Use of Multispectral Radiometry for Assessment of Rhizoctonia Blight in Creeping Bentgrass

1998 ◽  
Vol 88 (5) ◽  
pp. 446-449 ◽  
Author(s):  
C. Raikes ◽  
L. L. Burpee
Keyword(s):  
Disease Severity ◽  
Regression Models ◽  
Plant Disease ◽  
Near Infrared ◽  
Linear Regression Analysis ◽  
Creeping Bentgrass ◽  
Anastomosis Group ◽  
Disease Assessment ◽  
Canopy Reflectance ◽  
Group 2

The ability to identify diseases early and quantify severity accurately is crucial in plant disease assessment and management. This study was conducted to assess changes in the spectral reflectance of sunlight from plots of creeping bentgrass during infection by Rhizoctonia solani, the cause of Rhizoctonia blight, and to evaluate multispectral radiometry as a tool to quantify Rhizoctonia blight severity. After inoculation of 6-year-old creeping bentgrass turf with R. solani anastomosis group 2-2, reflectance of sunlight from the foliar canopy was measured at light wavelengths of 460 nm (blue) to 810 nm (near infrared [NIR]), at 50-nm intervals. Visual estimates of disease severity and percentage of canopy reflectance were made daily throughout each of three epidemics of Rhizoctonia blight from the onset of visible symptoms until maximum disease severity was reached. In each experiment, linear regression analysis revealed a significant reduction in the percentage of NIR (760 and 810 nm) reflectance as disease severity increased. However, in the majority of analyses, regression models explained <50% of the variability between components. Multispectrum radiometry appears to function best when used to assess differences in disease severity at discrete points in time rather than over an entire epidemic.

scholarly journals Phoma Leaf Spot Susceptibility and Horticultural Characteristics of Table Beet Cultivars in New York

2019 ◽  
Vol 20 (2) ◽  
pp. 95-103 ◽  
Author(s):  
Lori B. Koenick ◽  
Julie R. Kikkert ◽  
Sarah J. Pethybridge
Keyword(s):  
New York ◽  
Leaf Spot ◽  
Dry Weight ◽  
Field Trials ◽  
Root Weight ◽  
Fresh Weight ◽  
Fresh Market ◽  
Cultivar Selection ◽  
Small Plot ◽  
Phoma Betae

Phoma leaf spot (PLS), caused by Phoma betae (syn. Neocamarosporium betae), is an important fungal disease affecting table beet (Beta vulgaris L. subsp. vulgaris) production in New York. PLS lesions on the foliage can lead to rejection in fresh market sales and can reduce leaf integrity, which can disrupt mechanized harvesting. Eight popular table beet cultivars were assessed for susceptibility to PLS using P. betae isolates representative of the New York population in two small-plot, replicated field trials in Geneva and Freeville, NY. There were significant differences in PLS incidence, severity, and epidemic progress (as measured by area under the disease progress stairs) and horticultural characteristics among cultivars. Non-red table beet cultivars (Avalanche, Boldor, and Chioggia Guardsmark) were less susceptible to PLS than red cultivars (Falcon, Merlin, Rhonda, Red Ace, and Ruby Queen). Significant differences in fresh weight of roots and dry weight of foliage were detected between cultivars at harvest (86 days after planting [DAP] in Freeville and 91 DAP in Geneva). Falcon had significantly higher root weight than Boldor, and Ruby Queen produced significantly more foliage than Boldor. Information on the performance of these cultivars provides locally valuable information for cultivar selection in a broad range of markets.

Improving fungicide-based management of Cercospora leaf spot in table beet in New York, USA

2019 ◽  
Vol 42 (3) ◽  
pp. 353-366 ◽  
Author(s):  
Sarah J. Pethybridge ◽  
Sandeep Sharma ◽  
ZACHARIAH R. Hansen ◽  
Niloofar Vaghefi ◽  
Linda E. Hanson ◽  
...  
Keyword(s):  
New York ◽  
Leaf Spot ◽  
Cercospora Leaf Spot

Comparison of two disease assessment methods for assessing Cercospora leaf spot in sugar beet

2003 ◽  
Vol 22 (1) ◽  
pp. 201-209 ◽  
Author(s):  
J Vereijssen ◽  
J.H.M Schneider ◽  
A.J Termorshuizen ◽  
M.J Jeger
Keyword(s):  
Sugar Beet ◽  
Leaf Spot ◽  
Assessment Methods ◽  
Disease Assessment ◽  
Cercospora Leaf Spot

scholarly journals Use of a Multispectral Radiometer for Noninvasive Assessments of Foliar Disease Caused by Ray Blight in Pyrethrum

Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1397-1406 ◽  
Author(s):  
Sarah J. Pethybridge ◽  
Frank Hay ◽  
Paul Esker ◽  
Calum Wilson ◽  
Forrest W. Nutter
Keyword(s):  
Near Infrared ◽  
Ground Level ◽  
Visual Assessment ◽  
Disease Assessment ◽  
Infrared Range ◽  
Canopy Reflectance ◽  
Intensity Measures ◽  
Foliar Disease ◽  
Ray Blight ◽  
Vegetative Indices

Foliar disease due to ray blight (Phoma ligulicola) in pyrethrum was quantified at three locations over 2 years in Tasmania, Australia. To obtain a range of ray blight disease intensities, replicated plots were treated with fungicides that varied in efficacy to control ray blight. Visual disease assessments and measurement of canopy reflectance were made at least once during spring (September through December). Visual assessments involved removal of flowering stems at ground level from which measurements of defoliation severity and the incidence of stems with ray blight were obtained. Reflectance of sunlight from pyrethrum canopies was measured at 485, 560, 660, 830, and 1,650 nm using a handheld multispectral radiometer. Measurements from these wavelengths also were used to calculate all possible reflectance ratios, as well as four vegetative indices. Relationships between wavelength bands, reflectance ratios, vegetative indices, and disease intensity measures were described by linear regression analyses. Several wavelength bands, ratios, and vegetative indices were significantly related in a linear fashion to visual measures of disease intensity. The most consistent relationships, with high R2 and low coefficients of variation values, varied with crop growth stage over time. The ratio 830/560 was identified as the best predictor of stem height, defoliation severity, and number of flowers produced on each stem in October. However, reflectance within the near-infrared range (830 nm) and the difference vegetative index was superior in November. The use of radiometric assessment of disease was noninvasive and provided savings in disease assessment time, which is critical where visual assessment is difficult and requires destructive sampling, as with pyrethrum.

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