Assessing the Adequacy of the Simulation Model LATEBLIGHT Under Nicaraguan Conditions

In this study, the adequacy of the late blight simulation model LATEBLIGHT (version LB2004) was evaluated under Nicaraguan conditions. During 2007 to 2008, five field experiments were conducted in three potato-production regions in northern Nicaragua. Two susceptible (‘Cal White’ and ‘Granola’) and one resistant (‘Jacqueline Lee’) potato cultivars were evaluated without use of fungicides and with three application intervals (4, 7, and 14 days) of the fungicide chlorothalonil. The simulation model was considered adequate because it accurately predicted high disease severity in susceptible cultivars without fungicide protection, and demonstrated a decrease in the disease progress curves with additional fungicide applications, similar to that observed in the plots. The model also generally predicted inadequate fungicide control, even with a 4-day spray interval, which also occurred in the field. Lack of adequate fungicide protection would indicate the need for cultivars with higher levels of durable resistance, and that farmers should consider more effective fungicides applications (higher dosages or different chemistries) if susceptible cultivars are used.

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Yield and resistance of potato cultivars with colour flesh to potato late blight

Plant Soil and Environment ◽

10.17221/371/2017-pse ◽

2017 ◽

Vol 63 (No. 7) ◽

pp. 328-333

Author(s):

Pazderů Kateřina ◽

Hamouz Karel

Keyword(s):

Late Blight ◽

Field Experiments ◽

Potato Late Blight ◽

Russet Burbank ◽

Weak Dependence ◽

Potato Cultivars ◽

Disease Progress Curve ◽

Disease Progress ◽

Progress Curve ◽

Better Than

The resistance to potato late blight (as AUDPC – the area under the disease progress curve) and yield were evaluated in precise field experiments with 13 colour-fleshed potato cultivars. Red Emmalie and Blaue Anneliese were the most profitable cultivars of potatoes with coloured flesh, the overall yield did not differ statistically from the control cv. Agria. Cv. Blaue Anneliese resistance to potato late blight was considerably better than both control cultivars, other 2 cultivars HB Red and Red Emmalie were similar to cv. Agria. Surprisingly, cv. Russet Burbank was found to be more resistant than most cultivars tested. A statistically significant weak dependence (r = 0.36) between the percentage of infestation of plants in the T6 evaluation date (6–8 August in individual years) and the yield was detected, the slightly stronger (r = 0.40) was the correlation between AUDPC values and total yields.

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Varietal responses and quantitative contribution of nutrients to potato production

The Journal of Agricultural Science ◽

10.1017/s0021859600081363 ◽

1988 ◽

Vol 110 (2) ◽

pp. 331-335 ◽

Cited By ~ 2

Author(s):

R. C. Sharma ◽

H. C. Sharma

Keyword(s):

Dry Matter ◽

Field Experiments ◽

Alluvial Soil ◽

Potato Production ◽

Potato Cultivars ◽

Quantitative Contribution

SummaryField experiments, conducted on alluvial soil of Jalandhar during 1984–5 and 1985–6 with four rates of application each of N, P and K and four potato cultivars, Badshah, Bahar, Lalima and Jyoti, revealed significant responses to N and K. Badshah, Bahar and Lalima responded to 240 kg N/ha while Jyoti responded to 160 kg N/ha. Badshah did not respond to K. Bahar responded to 150 K/ha whereas both Jyoti and Lalima responded to 50 kg K/ha. Varietal responses to N were related to yield and crop duration while the responses to K were related to K composition of tubers. N showed inconsistent effect on percentage dry matter of tubers, but K decreased it. N increased concentration of N and P but decreased that of K.

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Suppression of Sclerotinia Stem Rot of Soybean by Lactofen Herbicide Treatment

Phytopathology ◽

10.1094/phyto.1999.89.7.598 ◽

1999 ◽

Vol 89 (7) ◽

pp. 598-602 ◽

Cited By ~ 58

Author(s):

E. K. Dann ◽

B. W. Diers ◽

R. Hammerschmidt

Keyword(s):

Disease Severity ◽

Field Experiments ◽

Lesion Size ◽

Stem Rot ◽

Growth Stages ◽

Sclerotinia Stem Rot ◽

High Disease Severity ◽

Disease Pressure ◽

Seed Yields ◽

Field Plots

Severity of Sclerotinia stem rot of soybean after treatment with lactofen (Cobra) and other herbicides was assessed in field experiments conducted in Michigan from 1995 to 1997. At sites where disease pressure was high, disease severity was reduced 40 to 60% compared with controls when lactofen was applied at the V3 (1995 and 1996) or R1 (1997) growth stages. Corresponding seed yields were unchanged or up to 20% greater when lactofen was applied at the R1 stage in 1997. Disease severity was not reduced by lactofen treatments in years and at sites where disease pressure was low to medium, and corresponding yields often were reduced by ≈10%. High levels of glyceollin accumulated in lactofen-injured leaves collected from field plots in 1996 and 1997. High glyceollin content in lactofen-treated leaves was associated with significant reductions in lesion size when leaves were challenge-inoculated with Sclerotinia sclerotiorum.

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Automatic late blight lesion recognition and severity quantification based on field imagery of diverse potato genotypes by deep learning

10.1101/2020.08.27.263186 ◽

2020 ◽

Author(s):

Junfeng Gao ◽

Jesper Cairo Westergaard ◽

Ea Høegh Riis Sundmark ◽

Merethe Bagge ◽

Erland Liljeroth ◽

...

Keyword(s):

Deep Learning ◽

Late Blight ◽

Disease Severity ◽

Severe Disease ◽

Learning Algorithms ◽

Resistance Breeding ◽

Potato Production ◽

Majority Voting ◽

Lesion Segmentation ◽

Fast Evaluation

AbstractThe plant pathogen Phytophthora infestans causes the severe disease late blight in potato, which results in a huge loss for potato production. Automatic and accurate disease lesion segmentation enables fast evaluation of disease severity and assessment of disease progress for precision crop breeding. Deep learning has gained tremendous success in computer vision tasks for image classification, object detection and semantic segmentation. To test whether we could extract late blight lesions from unstructured field environments based on high-resolution visual field images and deep learning algorithms, we collected ~500 field RGB images in a set of diverse potato genotypes with different disease severity (0-70%), resulting in 2100 cropped images. 1600 of these cropped images were used as the dataset for training deep neural networks. Finally, the developed model was tested on the 250 cropped images. The results show that the intersection over union (IoU) values of background (leaf and soil) and disease lesion classes in the test dataset are 0.996 and 0.386, respectively. Furthermore, we established a linear relationship (R2 = 0.655) between manual visual scores of late blight and the number of lesions at the canopy level. We also learned that imbalance weights of lesion and background classes improved segmentation performance, and that fused masks based on the majority voting of the multiple masks enhanced the correlation with the visual scores. This study demonstrates the feasibility of using deep learning algorithms for disease lesion segmentation and severity evaluation based on proximal imagery for crop resistance breeding in field environments.

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Use Of a Simulation Model to Explore Fungicide Strategies for Control of Cercospora Leafspot of Peanut1

Peanut Science ◽

10.3146/i0095-3679-15-1-11 ◽

1988 ◽

Vol 15 (1) ◽

pp. 39-43 ◽

Cited By ~ 4

Author(s):

G. R. Knudsen ◽

C. S. Johnson ◽

H. W. Spurr

Keyword(s):

Simulation Model ◽

Disease Severity ◽

Weather Conditions ◽

Field Trials ◽

Computer Simulation Model ◽

Financial Benefit ◽

Advisory Program ◽

Disease Progress Curve ◽

Disease Progress ◽

Progress Curve

Abstract A sub-model describing persistence and efficacy of chlorothalonil fungicide was incorporated into a computer simulation model of Cercospora leafspot of peanut. The resultant model was validated using independent data sets from field trials over a two-year period. Predicted disease progress curves and area under the disease progress curve for different fungicide application schedules and rates were compared with field observations. The model was then used to compare predicted disease severity and area under the disease progress curve (AUDPC) for a calendar spray schedule vs a leafspot advisory program under different weather conditions. Predicted disease severity levels and area under disease progress curves were similar for advisory and calendar spray schedules. Results were insensitive to changes in parameters describing fungicide persistence or efficacy. The model described herein is a good estimator of the combined effects of weather and chlorothalonil treatments on disease progress, effectively ranks treatments or environmental conditions in terms of their effect on leafspot, and provides a basis for comparison of fungicide scheduling strategies. The simulation model predicted AUDPC more accurately than end-of-season disease, and AUDPC is a more reliable indicator of the effect of peanut leafspot disease on yield loss. Simulation experiments will be useful in optimizing fungicide or biocontrol strategies for long-term financial benefit to growers.

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A complex resistance locus in Solanum americanum recognizes a conserved Phytophthora effector

10.1101/2020.05.15.095497 ◽

2020 ◽

Cited By ~ 4

Author(s):

Kamil Witek ◽

Xiao Lin ◽

Hari S Karki ◽

Florian Jupe ◽

Agnieszka I Witek ◽

...

Keyword(s):

Late Blight ◽

Broad Spectrum ◽

Durable Resistance ◽

Late Blight Resistance ◽

Potato Production ◽

Blight Resistance ◽

Resistance Locus ◽

Family Diversity ◽

Long Read ◽

Solanum Americanum

AbstractLate blight caused by Phytophthora infestans greatly constrains potato production. Many Resistance (R) genes were cloned from wild Solanum species and/or introduced into potato cultivars by breeding. However, individual R genes have been overcome by P. infestans evolution; durable resistance remains elusive. We positionally cloned a new R gene, Rpi-amr1, from Solanum americanum, that encodes an NRC helper-dependent CC-NLR protein. Rpi-amr1 confers resistance in potato to all 19 P. infestans isolates tested. Using association genomics and long-read RenSeq, we defined eight additional Rpi-amr1 alleles from different S. americanum and related species. Despite only ∼90% identity between Rpi-amr1 proteins, all confer late blight resistance but differentially recognize Avramr1 orthologs and paralogs. We propose that Rpi-amr1 gene family diversity facilitates detection of diverse paralogs and alleles of the recognized effector, enabling broad-spectrum and durable resistance against P. infestans.

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Economic Management of Late Blight (Phytophthora infestans L.) of Potato in Eastern Tarai of Nepal

Nepal Agriculture Research Journal ◽

10.3126/narj.v6i0.3365 ◽

1970 ◽

Vol 6 ◽

pp. 57-61 ◽

Cited By ~ 3

Author(s):

Prem CP Chaurasia

Keyword(s):

Late Blight ◽

Disease Severity ◽

Field Experiments ◽

Tuber Yield ◽

Block Design ◽

Winter Season ◽

Cost Ratio ◽

Research Station ◽

Terminal Disease ◽

Progress Curve

Field experiments were carried out at Regional Agriculture Research Station, Tarahara in threeconsecutive years (1997-2000) during winter season to know the economic sprays of differentfungicides to manage late blight disease of potato. Late blight susceptible cultivar of potatoKufri Sindhuri was used for the experiment. Krinoxyl gold (metalaxyl 8% and mancozeb 64%)at the rate of 1.5 g/l, Dithane M- 45 (mancozeb 75%) @ 0.3% and Bordeaux mixture @ 10 gcopper sulfate and 10 g lime/l of water and their different combinations were tested inrandomized complete block design with three replications. Terminal disease severity was thehighest (7.9) on 0-9 scale disease rating in unsprayed check and it was significantly higher thanthose of other fungicides sprays. Plots with three sprays of Dithane M- 45 @ 0.3% recorded thelowest (2.4) terminal disease severity. Disease development was the fastest in the unsprayed plotcompared to all other treatments. Similarly apparent infection rate was the highest in unsprayedtreatment. Area Under the Disease Progress Curve was also the highest in unsprayed plot and itwas significantly higher than those of other treatments. Tuber yield was the lowest (3.93 kg/4.5m2 plot in unsprayed and the highest (6.08 kg), in the plot receiving four sprays of Dithane M-45@ 0.3 % and this was at par with the tuber yield of plots receiving two and three sprays ofDithane M-45. Benefit cost ratio was the highest (1.54) in case of two sprays of Dithane M-45@ 0.3% at 10 days intervals. All others fungicide spays were uneconomical under Eastern Taraicondition.Key words: Eastern Tarai; economic spray; Dithane M-45; late blight management; potatoDOI: 10.3126/narj.v6i0.3365Nepal Agriculture Research Journal Vol.6 2005 pp.57-61

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Performance of potato cultivars in an organic farming system using organic fertilizers, vermicompost and azolla

Australian Journal of Crop Science ◽

10.21475/ajcs.21.15.07.p3289 ◽

2021 ◽

pp. 1081-1088

Author(s):

Amal K. Abou El- Goud ◽

Fahad R. Al- Masoodi ◽

Karam A. Elzopy ◽

Mona M. Yousry

Keyword(s):

Vegetative Growth ◽

Field Experiments ◽

Growth Parameters ◽

Organic Fertilizer ◽

Growth Yield ◽

Dry Weight ◽

Potato Production ◽

Potato Cultivars ◽

Organic Fertilizers ◽

Agricultural Practice

The challenges of food shortages and environmental pollution require the development of safe and effective alternatives to chemical fertilizers. Two field experiments were conducted during the summer season of 2019/2020 in two locations on a private farm to evaluate the performance of three potato cultivars (Sponta, Cara, and Elbieda) under different fertilizer treatments. The experiment was laid out in a split-plot design replicated thrice. The main plots had three potato cultivars, while the sub plots were comprised of seven fertilizer treatments. The results showed that the highest vegetative growth characters, viz. plant height, leaf chlorophyll index, and plant dry weight were produced by Sponta, followed by Cara, while the lowest growth attributes were recorded in Elbeida. Compared to the NPK inorganic fertilizer, organic fertilizers significantly improved the vegetative growth characteristics of potato in all treatments. Among the organic treatments, the highest growth parameters were recorded with the application of mixed organic fertilizer, vermicompost, and Azollapinnata (T1). The highest yield, viz. tuber yield, number of tubers per plant, and tuber weight, and yield quality characteristics, viz. total carbohydrates, starch, and TSS, were also recorded in T1. Our results demonstrate that the Sponta cultivar grown with the application of mixed organic fertilizer, vermicompost, and Azollapinnata (T1) produced the highest growth, yield, and quality of potato tubers. Thus, we recommend this treatment combination as a sustainable agricultural practice for potato production in similar areas

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REACTION OF POTATO CULTIVARS AND CLONES TO Phytophthora infestans

Revista Caatinga ◽

10.1590/1983-21252019v32n212rc ◽

2019 ◽

Vol 32 (2) ◽

pp. 390-398

Author(s):

VICTOR HUGO CASA-COILA ◽

CESAR BAUER GOMES ◽

ISRAEL LIMA-MEDINA ◽

DEDIEL JUNIOR AMARAL ROCHA ◽

ARIONE DA SILVA PEREIRA ◽

...

Keyword(s):

Phytophthora Infestans ◽

Disease Severity ◽

Field Experiments ◽

Tuber Yield ◽

Field Tests ◽

Potato Cultivars ◽

In Vitro Test ◽

Progress Curve ◽

Vitro Test

ABSTRACT The in vitro and field reactions of 23 potato cultivars and clones to two isolates of Phytophthora infestans were tested. The in vitro test used the detached potato leaflets method, and disease severity was evaluated 6 days after inoculation. Field experiments were conducted in autumn of 2013, in two locations in Pelotas City, Rio Grande do Sul State, Brazil. Seven evaluations of the disease severity were performed. From the severity values, the area under the disease progress curve (AUDPC) was calculated. Tubers were harvested to determine the yield (g plot-1). The A2 mating type isolate was the most aggressive for the majority of the potato genotypes. It was possible to group the different reactions of the potato genotypes based on the AUDPC values. Clones C2553-1-06, C2573-4-06, C2550-4-06, C2551-2-06, and CIP392,617.54 showed moderate-to-high resistance to the two isolates of P. infestans. The values of severity and AUDPC obtained in vitro and field tests were positively correlated for both P. infestans isolates, but in some interactions, inconsistencies were observed. Tuber yield was negatively correlated with AUDPC.

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