Evaluation of a Weather-Based Spray Advisory for Management of Early Leaf Spot of Peanut in Oklahoma1

1994 ◽  
Vol 21 (2) ◽  
pp. 115-121 ◽  
Author(s):  
J. P. Damicone ◽  
K. E. Jackson ◽  
J. R. Sholar ◽  
M. S. Gregory
Keyword(s):  
Post Infection ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Cercospora Arachidicola ◽  
Advisory Program ◽  
Arachis Hypogea ◽  
Progress Curve ◽  
Weather Stations ◽  
Improved Performance ◽  
And Control

Abstract A simplified version of the weather-based advisory program developed by Parvin, Smith, and Crosby (PSC) for scheduling fungicide sprays for management of early leaf spot (Cercospora arachidicola Hori) of peanut (Arachis hypogea L.) was evaluated under various productions systems in Oklahoma from 1990-1992. Over eight trials with spanish cultivars, the number of sprays per season averaged 5.7 for the 14-d schedule and 4.0 for the advisory program. Final disease incidence (symptomatic and defoliated leaflets) with the fungicide chlorothalonil (1.26 kg/ha) averaged 15% for the 14-d schedule, 34% for the advisory program, and 77% for the control. However, disease incidence (75%) and defoliation (50%) approached unacceptable levels on the spanish cultivars in some trials. In six trials with runner cultivars, the number of sprays averaged 6.7 for the 14-d schedule and 4.7 for the advisory program. Final disease incidence with chlorothalonil on the runner cultivars averaged 5% for the 14-d schedule, 14% for the advisory program, and 68% in the control. Yields did not differ in any of the 14 trials between the advisory and 14-d programs using chlorothalonil. Yields averaged 3015, 3003, and 2303 kg/ha for spanish cultivars and 4108, 3855, and 3066 kg/ha for runner cultivars with the 14-d schedule, advisory program, and control, respectively. The advisory program was effective in irrigated trials where weather stations were deployed either under or outside the influence of irrigation. The fungicides tebuconazole at 0.14 kg/ha and propiconazole at 0.13 kg/ha generally provided better leaf spot control with the advisory program than chlorothalonil. The post-infection activity of these fungicides was observed in one trial and probably accounts for their improved performance. Yields were reduced and leaf spot incidence was high where tank mixes of benomyl (0.28 kg/ha) or thiophanatemethyl (0.38 kg/ha) plus mancozeb (1.68 kg/ha) were used with the advisory program. Area under the disease progress curve, leaf spot incidence, and defoliation in the controls were lower for runner than for spanish cultivars at sites where both market types were planted in adjacent trials. Fungicides applied according to the advisory program provided better leaf spot control on the runner cultivars. Results showed the need for a weather-based advisory which allows greater levels of leaf spot control on spanish cultivars than the PSC advisory.

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

Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 263-268 ◽  
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.

scholarly journals Screening of different plant extracts against leaf spot (Cercospora arachidicola and Cercosporidium personatum) of groundnut (Arachis hypogaea L.)

2013 ◽  
Vol 38 (3) ◽  
pp. 491-503 ◽  
Author(s):  
MH Hossain ◽  
I Hossain
Keyword(s):  
Plant Extracts ◽  
Leaf Spot ◽  
Growth Parameters ◽  
Disease Incidence ◽  
Foliar Spray ◽  
Plain Water ◽  
Infected Leaf ◽  
Cercospora Arachidicola ◽  
Cercosporidium Personatum ◽  
Almost All

A study was undertaken to evaluate effectiveness of foliar spray with 33 plant extracts against leaf spot (Tikka) of groundnut caused by Cercospora arachidicola and Cercosporidium personatum. Bavistin and BAU-Biofungicide were included in the experiment as checks and spray of plain water represented control. Almost all treatments gave considerable reduction in disease incidence and increase in growth parameters, pod and haulm yield compared to control. The most effective materials were Bavistin 50 WP, BAU-Biofungicide, leaf extract of neem, tomato, datura black, and datura white. The materials decreased spot number per leaf, defoliation per plant, incidence of leaf spot, and number of infected leaf per plant by 35.45 -60.07, 42.06-72.20, 51.97–63.58, and 38.33 to 46.89 % and increased pod yield and haulm yield by 64.37-111.41 and 32.35- 74.71 %, respectively. The materials may be recommended against the disease after economic analysis. DOI: http://dx.doi.org/10.3329/bjar.v38i3.16976 Bangladesh J. Agril. Res. 38(3): 491-503, September 2013

Effect of In-Furrow and Early-Season Banded Applications of Fungicides on Incidence of Early Leaf Spot of Peanut

2015 ◽  
Vol 16 (4) ◽  
pp. 225-229
Author(s):  
Albert K. Culbreath ◽  
Robert C. Kemerait ◽  
Yun-Ching Tsai ◽  
Timothy B. Brenneman ◽  
Katherine L. Stevenson ◽  
...  
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Field Experiments ◽  
Disease Incidence ◽  
Cercospora Arachidicola ◽  
Early Season ◽  
Fungicide Application

Field experiments were conducted in Tifton, GA, in 2012-2014 to determine the effect of in-furrow applications of prothioconazole and early-season banded applications of prothioconazole or pyraclostrobin on incidence of early leaf spot (Cercospora arachidicola) of peanut (Arachis hypogaea). In each year, border rows were planted in May as a source of inoculum for plants in the treatment plots. Plots were planted in August or September after epidemics of early leaf spot were severe in the border plots. Fungicide application regimes included two rates (100 and 200 g a.i./ha) of prothioconazole applied in-furrow at planting, and 200 g a.i./ha of prothioconazole or 164 g a.i./ha of pyraclostrobin applied concentrated in a 30-cm band 21 days after planting (DAP). Incidence (percent of leaflets with one or more leaf spot) of early leaf spot was monitored until 54 to 57 days after planting in each year. In all years, disease incidence was below 10% at 28 DAP in plots treated with 200 g a.i./ha of prothioconazole in-furrow compared to over 40% in nontreated plots at the same time. In-furrow applications of 100 g a.i./ha of prothioconazole were less effective, but suppressed leaf spot incidence compared to the control. Banded applications of either fungicide at 21 DAP resulted in a decrease in leaf spot incidence, and prevented increase in leaf spot incidence for 19 days or longer. Accepted for publication 30 November 2015. Published 3 December 2015.

scholarly journals Effective Plant Ages for Screening for Field Resistance to Alternaria Leaf Spot (Caused by Alternaria spp.) under Natural Infection in Jerusalem artichoke (Helianthus tuberosus L.)

Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 754 ◽  
Author(s):  
Wanalai Viriyasuthee ◽  
Suwita Saepaisan ◽  
Weerasak Saksirirat ◽  
Mark L. Gleason ◽  
Ruey Shyang Chen ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Natural Infection ◽  
Block Design ◽  
Jerusalem Artichoke ◽  
Plant Age ◽  
Growth Stages ◽  
Alternaria Leaf Spot ◽  
Progress Curve ◽  
The Impact

Host plant resistance has proven to be effective for controlling Alternaria leaf spot on Jerusalem artichoke (JA), but efficient screening techniques have not been developed yet. The objective of this study is to estimate the relationship between disease resistance parameters of JA as a function of plant age. Six JA varieties and three plant ages at the time of inoculation (20, 40 and 60 days after transplanting) (DAT) are evaluated in a factorial experiment in randomized complete block design (RCBD) with four replications. Disease incidence (DI) and severity (DS) are estimated, from which area under the disease progress curve (AUDPC) was calculated. Disease parameters are positively and significantly correlated for plant ages of 40 and 60 DAT. Based on our results, screening of JA at 40 DAT for resistance to Alternaria leaf spot is recommended. Knowledge of the impact of plant age on resistance to key diseases can help breeders to accelerate breeding programs so superior genotypes can be identified before reproductive growth stages.

scholarly journals Diallel Analysis of Early Leaf Spot (Cercospora arachidicola Hori) Disease Resistance in Groundnut

Agronomy ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 15 ◽  
Author(s):  
Adama Zongo ◽  
Abdourasmane K. Konate ◽  
Kadidia Koïta ◽  
Mahamadou Sawadogo ◽  
Philippe Sankara ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Leaf Spot ◽  
Gene Action ◽  
Block Design ◽  
Regression Line ◽  
Cercospora Arachidicola ◽  
Additive Gene Action ◽  
Progress Curve ◽  
Additive Gene ◽  
Resistance Traits

Early leaf spot (ELS) is one of the major biotic constraints of groundnut production in West and Central Africa. A study using 6 × 6 F2 full diallel populations from six parents (NAMA, B188, PC79-79, QH243C, TS32-1, and CN94C) was conducted to assess the mode of inheritance of ELS resistance traits. The F2 and parents were grown in a randomized complete block design with three replications. Data was collected on ELS disease severity, and an area under disease progress curve (AUDPC) was estimated. The results revealed that additive and non-additive gene actions were involved in the inheritance of the ELS resistance traits, but additive gene action was predominant. Significant reciprocal cross effect was observed, suggesting cytoplasmic effect on ELS resistance. Graphical analysis also revealed the predominance of additive gene action for ELS resistance. The results suggest that early generation selection should be effective for ELS resistance. Looking at the distribution of array points along with the regression line, parental lines NAMA, PC79-79, and B188 would be suitable as good donors in an ELS disease resistance breeding program.

scholarly journals Rational Use of Fungicide Applications to Maximize Peanut Yield Under Foliar Disease Pressure in West Africa

Plant Disease ◽  
2000 ◽  
Vol 84 (11) ◽  
pp. 1203-1211 ◽  
Author(s):  
F. Waliyar ◽  
Moustapha Adamou ◽  
Aoua Traoré
Keyword(s):  
West Africa ◽  
Leaf Spot ◽  
Field Trials ◽  
Cercospora Arachidicola ◽  
Causal Organism ◽  
Late Leaf Spot ◽  
Pod Yield ◽  
Progress Curve ◽  
The Cost ◽  
Disease Pressure

Foliar diseases caused by Cercospora arachidicola, Cercosporium personatum, and Puccinia arachidis are major constraints to peanut production in the world. Fungicides are among the most efficient available control methods. Field trials were conducted in 1991 and 1992 in Benin and Niger, West Africa, to evaluate the cost effectiveness of fungicide application timings and frequencies on four peanut cultivars. A combination of four timings (40, 55, 70, and 85 days after sowing) was scheduled. Early (causal organism, C. arachidicola) and late (caused by C. personatum) leaf spot were prevalent in both years, but late leaf spot was the more economically important disease as shown by high values of area under the disease progress curve. Application of fungicide reduced late leaf spot incidence and increased pod yield. Pod yield responded to an interaction of number and timing of fungicide applications. With appropriate timing two or three fungicide applications were enough to significantly increase pod yield. Properly timed fungicide sprays can result in substantial monetary gains for peanut farmers in West Africa.

scholarly journals Responses of Peanut Genotypes to Fungicidal Control of Early Leaf Spot in Malawi1

1997 ◽  
Vol 24 (2) ◽  
pp. 73-77 ◽  
Author(s):  
P. Subrahmanyam ◽  
G. L. Hildebrand
Keyword(s):  
Leaf Spot ◽  
Yield Potential ◽  
Total Biomass ◽  
Cercospora Arachidicola ◽  
Beneficial Effects ◽  
Growing Seasons ◽  
Arachis Hypogaea L ◽  
Excellent Control ◽  
Yield Responses ◽  
And Control

Abstract Early leaf spot (Cercospora arachidicola Hori.) is the most destructive disease of peanut (Arachis hypogaea L.) in Malawi. Fifteen peanut genotypes were examined for their response to fungicidal control of early leaf spot during the 1990/91 (year 1), 1991/92 (year 2), and 1992/93 (year 3) growing seasons at Chitedze, Malawi. Total rainfall and its distribution in these years were variable, with the most favorable pattern in year 3. Early leaf spot was most severe in year 2, although there was a severe midseason drought during this year. Fungicide application gave excellent control of the disease in all growing seasons. The cultivar Malimba had the most damage and the breeding line ICGV-SM 85053 had the least damage from early leaf spot. Pod yields were higher in year 3 than in the other two growing seasons. Pod yields were significantly higher in fungicide-sprayed (treated) plots than in water-sprayed (control) plots in years 1 and 3. Most peanut genotypes had positive yield responses to disease control in years 1 and 3. However, there were no significant differences in pod yields between treated and control plots of most genotypes in year 2. Although the pod yields were lower in year 2 than in year 1, total biomass production was higher in year 2. It was apparent that biomass partitioning was severely affected in year 2 due to the midseason drought stress that reduced pod yields and vitiated the beneficial effects of fungicidal application. Investment in fungicidal control of early leaf spot on genotypes with low yield potential may not be economical under less than optimal rainfall conditions.

scholarly journals Effect of botanicals and biofungicide on controlling tikka disease (Cercospora sp.) of groundnut (Arachis hypogea L.)

2016 ◽  
Vol 39 (1) ◽  
Author(s):  
M. M. Hasan ◽  
I. Hossain ◽  
M. A. Kashem ◽  
M. M.A. Mondal ◽  
M. Y. Rafii ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Field Research ◽  
Cost Ratio ◽  
Cercospora Arachidicola ◽  
Higher Plant ◽  
Benefit Cost Ratio ◽  
Arachis Hypogea ◽  
Pod Yield ◽  
Datura Metel ◽  
Vigour Index

The leaf spot or Tikka disease (<italic>Cercospora arachidicola</italic> and <italic>Cercosporidium personatum</italic>) of groundnut (<italic>Arachis hypogea</italic> L<italic>.</italic>) is a predominant, devastating and economically important foliar fungal disease and a major yield reducing factor of groundnut, not only in Bangladesh, but also all over the world. The yield loss was calculated in the groundnut variety Dhaka-1 due to early and late leaf spot (Tikka) by over 30-48% in Bangladesh. The efficacy of NLEFS (<italic>Azadirachta indica</italic>), DebLEFS (<italic>Polyalthia longifolia</italic>), DLEFS (<italic>Datura metel</italic>), <italic>Trichoderma</italic> based biofungicides (BBST, BBFS and BBSFS) along with a check (Bavistin) and control were evaluated in the pot and field research. Among the treatments, BBSFS, NLEFS, DLEFS and DebLEFS showed better performance in controlling leaf spot and increasing pod yield by 53.61, 51.91, 40.85 and 38.72%, respectively as compared to control in the field. In case of seedling germination, BBSFS gave 97.77% germination followed by NLEFS (88.14%), DLEFS (93.33%) and DebLEFS (95.55%). BBSFS produced higher length and weight of shoot and root and vigour index as compared to control. Maximum vigour index was observed under BBFS (1583.88). BBSFS gave higher plant height, number of leaves and minimum number of infected leaves in the pots and field as compared to control. Minimum leaf area diseased was obtained with BBSFS followed by Bavistin in the field. Biofungicide (BBST, BBFS and BBSFS), NLEFS, DLEFS and DebLEFS showed promising performance in number and weight of pods and pod yield in the pots and field. Maximum weight of pods/plant and weight of mature pods/plant was achieved with BBSFS (20.05 g and 18.55 g) followed by NLEFS (19.83 g and 18.22 g). The highest net profit was recorded with the use of BBSFS by Tk. 176768.00/ha followed by NLEFS Tk. 172275.00/ha, BBFS Tk. 168818.00/ha, while the lowest Tk. 96443.00/ha in untreated control. Maximum Benefit-Cost Ratio (BCR) 1: 2.77 was found in BBSFS followed by BBST (1: 2.65), BBFS (1: 2.64) and NLEFS (1:2.62).

scholarly journals Variability of Alternaria Leaf Spot Resistance in Jerusalem Artichoke (Helianthus Tuberosus L.) Accessions Grown in a Humid Tropical Region

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 268 ◽  
Author(s):  
Viriyasuthee ◽  
Saksirirat ◽  
Saepaisan ◽  
Gleason ◽  
Jogloy
Keyword(s):  
Disease Severity ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Jerusalem Artichoke ◽  
Severity Index ◽  
Field Conditions ◽  
Helianthus Tuberosus ◽  
Disease Severity Index ◽  
Alternaria Leaf Spot ◽  
Progress Curve

Alternaria leaf spot is an emerging disease of Jerusalem artichoke (Helianthus tuberosus L.) in tropical regions. The lack of known resistant germplasm sources is an important constraint to development of Jerusalem artichoke varieties with resistance to Alternaria leaf spot. The objectives of this study were to identify variability of Jerusalem artichoke genotypes for resistance to Alternaria leaf spot under field conditions and to investigate the relationships among resistance characters, yield, and yield components for selection of resistant varieties. Ninety six accessions of Jerusalem artichoke were evaluated in replicated trials under field conditions in early rainy and late rainy seasons in Khon Kaen, Thailand during 2014. Parameters evaluated included disease incidence, disease score, disease severity index, area under disease progress curve of disease incidence, area under disease progress curve of disease severity index, number of tubers/plants, tuber size, and fresh tuber yield. The genotypes HEL 335, HEL 256, HEL 317, HEL 308, and JA 86 were identified as sources of leaf spot resistance in both seasons. These genotypes can be used as sources of leaf spot resistance for Jerusalem artichoke breeding programs. HEL 293 and HEL 246 showed susceptibility to leaf spot disease in both seasons and should be used as standard susceptible checks.

scholarly journals First Report of Gray Leaf Spot Caused by Alternaria brassicae on Canola in Argentina

Plant Disease ◽  
2005 ◽  
Vol 89 (2) ◽  
pp. 207-207 ◽  
Author(s):  
S. Gaetán ◽  
M. Madia
Keyword(s):  
Leaf Spot ◽  
Buenos Aires ◽  
Disease Incidence ◽  
Leaf Tissue ◽  
Climatic Conditions ◽  
Gray Leaf Spot ◽  
Conidial Suspension ◽  
Alternaria Brassicae ◽  
First Report ◽  
And Control

Canola (Brassica napus) is a developing oleaginous crop grown commercially in Argentina. During 2003, typical symptoms of a foliar disease were observed on canola plants in experimental field plots in Buenos Aires. Average disease incidence across 14 6-month-old canola cultivars was 27% (range 12 to 42%). Climatic conditions in Buenos Aires during August 2003 included moderate temperatures and periods with high humidity, which were apparently favorable for disease development. Symptoms were observed on leaves, stems, and pods. Leaf symptoms were randomly distributed on the adaxial surfaces and consisted of zonate lesions of alternating light gray and dark brown areas that were 6 to 10 mm in diameter. Remaining leaf tissue was chlorotic and affected leaves abscised. Stem infections appeared as irregular and elongated black lesions, 0.7 to 1.2 cm long. Pods lesions were circular, 6 to 8 mm in diameter, gray in the center, and surrounded by a diffuse dark brown margin. The disease developed progressively from the lower leaves to the pods, resulting in premature senescence of the tissues, chlorosis, and defoliation. Conidiophores bearing conidia colonized the lesions as a dark gray growth of spore masses. Segments (0.5 cm long) taken from leaves, stems, and pods of diseased plants were dipped in 70% ethanol, surface sterilized with NaOCl (1%) for 2 min, and rinsed in sterile water. Each segment was blotted dry and placed on potato dextrose agar. Plates were incubated in the dark at 25°C for 2 to 3 days, followed by incubation under NUV light and a 12-h light/dark photoperiod for 6 to 8 days. Six fungal isolates were obtained. Fungal colonies were pale gray with dark concentric rings. Conidia were yellow to pale brown, ellipsoid to ovoid, produced singly or in short chains, with 8 to 10 transverse septa and 2 to 6 longitudinal septa. The spore body measured 13 to 22 × 68 to 135 µm with a beak cell 42 to 101 µm long. On the basis of conidial and cultural characteristics, the fungus was identified as Alternaria brassicae (Berk.) Sacc (1). Koch's postulates were completed for three isolates by spray-inoculating foliage of 6-week-old canola plants of cvs. Caviar, Dunkeld, Eclipse, Impulse, Mistral, and Sponsor with a conidial suspension (1 × 105 conidia per ml). The experiment, which included four inoculated plants and two noninoculated control plants for each cultivar per isolate, was conducted in the greenhouse at 22 to 24°C and maintained at 75% relative humidity with no supplemental light. Inoculated and control plants were covered with polyethylene bags for 48 h after inoculation. Within 12 days, inoculated plants developed small, brown lesions on leaves and stems for all three isolates; the pathogen was successfully reisolated in all instances. Control plants, inoculated only with sterile distilled water, remained symptomless. The experiment was repeated with similar results. The results suggest that A. brassicae may be a threat to the main cultivars being grown in Argentina. To our knowledge, this is the first report of A. brassicae causing gray leaf spot of canola in Argentina. Reference: (1) J. Joly. Le genre Alternaria. Recherches Physiologiques, Biologiques, et Systématiques. Paul Lechevalier, ed. Paris, France, 1964.

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