Genotype and Approved Fungicide Evaluation for Reducing Leaf Spot Diseases in Organically-Managed Peanut

2011 ◽  
Vol 12 (1) ◽  
pp. 4 ◽  
Author(s):  
Dylan Q. Wann ◽  
R. Scott Tubbs ◽  
Albert K. Culbreath
Keyword(s):  
Leaf Spot ◽  
Field Trials ◽  
Organic Production ◽  
Yield Potential ◽  
Organic Management ◽  
Late Leaf Spot ◽  
Stand Establishment ◽  
Synthetic Pesticide ◽  
Secondary Objective ◽  
Organically Managed

Growers interested in organic peanut (Arachis hypogaea) production need information to identify genotypes and acceptable fungicides for control of early and late leaf spot where synthetic pesticide applications are absent. Field trials were conducted in 2008-2010 to evaluate eleven peanut genotypes for leaf spot resistance and yield potential under organic management. CRSP 983 and Georganic demonstrated the greatest resistance to early and late leaf spot (18 to 59% and 34 to 52% defoliation, respectively), but Florida-07, Georgia-06G, and Tifguard produced the largest yields (2454 to 5424 kg/ha, 3758 kg/ha, and 1760 to 4030 kg/ha, respectively). Tifguard exhibited the best combination of stand establishment, disease resistance, and yield potential of all genotypes and would be a strong option for growers pursuing organic production. Florida-07 and Georgia-06G are also formidable options. A secondary objective was to evaluate the efficacy of three approved fungicides for leaf spot control on peanut under organic management. Copper sulfate + Bacillus subtilis reduced leaf spot defoliation compared to the control. Yet, all three fungicides improved yields under heavy leaf spot pressure. Combining high-yielding, disease-resistant cultivars and organically approved fungicides can significantly improve leaf spot management and yield potential of peanut under organic management. Accepted for publication 2 September 2011. Published 27 October 2011.

scholarly journals Effect of Planting Date and Peanut Cultivar on Epidemics of Late Leaf Spot in Georgia

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 990-995 ◽  
Author(s):  
Brian S. Jordan ◽  
Albert K. Culbreath ◽  
Timothy B. Brenneman ◽  
Robert C. Kemerait ◽  
Katherine L. Stevenson
Keyword(s):  
Leaf Spot ◽  
Seed Treatment ◽  
Field Trials ◽  
Planting Date ◽  
Organic Production ◽  
Linear Functions ◽  
Potential Utility ◽  
Plant Populations ◽  
Planting Dates ◽  
Late Leaf Spot

Field trials were conducted in 2015 and 2016 in Tifton, GA to determine the effects of planting dates (24 and 27 April, 4, 11, 19, and 26 May 2015; and 11, 18, and 25 April and 2, 9, and 16 May 2016), peanut (Arachis hypogaea) cultivar (Georgia-06G and Georgia-12Y), and seed treatment (nontreated and treated with azoxystrobin, fludioxonil, and mefenoxam) on epidemics of late leaf spot (Nothopassalora personata), plant populations, and peanut yield. Final severity and AUDPC of late leaf spot increased with later planting dates in both years. For most planting dates in 2015 and the final planting date in 2016, final leaf spot severity and AUDPC were lower for Georgia-12Y than for Georgia-06G. Seed treatment increased plant populations for the 27 April and 4 May planting dates in 2015 and across all other treatments in 2016. Yields were higher for Georgia-12Y than for Georgia-06G in both years. In 2015, yields of both cultivars decreased according to linear functions of day of year of planting date, but there was no effect of planting date on yield in 2016. The combination of early planting with Georgia-12Y shows potential utility for management of leaf spot in situations such as organic production where fungicide use is minimal.

Tine Cultivation Effects on Weed Control, Productivity, and Economics of Peanut under Organic Management

2011 ◽  
Vol 38 (2) ◽  
pp. 101-110 ◽  
Author(s):  
D.Q. Wann ◽  
R.S. Tubbs ◽  
W.C. Johnson ◽  
A.R. Smith ◽  
N.B. Smith ◽  
...  
Keyword(s):  
Weed Control ◽  
Growing Season ◽  
Field Trials ◽  
Organic Production ◽  
Annual Grass ◽  
Organic Management ◽  
Net Revenue ◽  
Peanut Cultivars ◽  
Hand Weeding ◽  
Organically Managed

ABSTRACT Identifying effective weed control regimes for organic peanut is paramount for improving the feasibility of organic production. Tine cultivation is a proven effective method for reducing in-row weed populations in several crops. Field trials were therefore conducted in 2008 and 2009 to assess the effects of tine cultivation combined with sweep cultivation and supplemental hand-weeding on weed control and overall productivity of two peanut cultivars under organic management. Tine cultivation regimes consisted of two frequencies (once per week or twice per week) for three durations (3 wk, 4 wk, or 5 wk). All cultivation treatments were also cultivated with flat sweeps at least once and hand-weeded periodically during the growing season. A non-cultivated, non-weeded control was included for comparison. All cultivation treatments significantly reduced annual grass populations in 2008 and Florida pusley populations both years. Cultivated treatments also resulted in denser plant stands for peanut (9.2 plants/m to 13.2 plants/m) than the non-cultivated control (5.9 plants/m to 7.9 plants/m). Pod yields in cultivated treatments ranged from 3502 kg/ha to 3823 kg/ha and were all significantly greater than yields in the non-cultivated control (1630 kg/ha). Also, net revenues generated by cultivated treatments ranged from ($3333/ha to $3637/ha) and were greater than that of the control ($1795/ha). Cultivation frequency had little effect on weed control and peanut productivity. However, the 4- and 5-wk durations displayed potential for improving peanut yield, grade, and net revenue over the 3-wk duration, especially when annual grass weeds were predominant. Cultivating once weekly for 4 or 5 wk with a tine cultivator, along with at least one sweep cultivation and supplemental hand-weeding, is a viable, economical option for providing adequate weed control and maximizing productivity of organically-managed peanut at current market premiums.

scholarly journals Late Leaf Spot Severity and Yield of New Peanut Breeding Lines and Cultivars Grown Without Fungicides

Plant Disease ◽  
2017 ◽  
Vol 101 (11) ◽  
pp. 1843-1850 ◽  
Author(s):  
Brian S. Jordan ◽  
Albert K. Culbreath ◽  
Timothy B. Brenneman ◽  
Robert C. Kemerait ◽  
William D. Branch
Keyword(s):  
Leaf Spot ◽  
Vegetation Index ◽  
Field Experiments ◽  
Organic Production ◽  
Canopy Reflectance ◽  
Cercospora Arachidicola ◽  
Early Season ◽  
Late Leaf Spot ◽  
Breeding Lines ◽  
Width Measurements

Peanut (Arachis hypogaea) cultivars with resistance or tolerance to Cercospora arachidicola and/or Cercosporidium personatum, the causes of early and late leaf spot, respectively, are needed for organic production in the southeastern U.S. To determine the potential of new breeding lines for use in such production systems, field experiments were conducted in Tifton, GA, in 2014 and 2015 in which nine breeding lines and two cultivars, Georgia-06G and Georgia-12Y, were grown without foliar fungicide applications. In one set of trials, cultivar Georgia-12Y and most of the breeding lines evaluated had early season vigor ratings, early-season canopy width measurements, final plant populations, and pod yield that were greater than those of standard cultivar Georgia-06G. In those trials, final late leaf spot Florida scale ratings were lower and canopy reflectance measured as the normalized difference vegetation index (NDVI), was higher all the breeding lines than those of Georgia-06G. In another set of trials, two of those same breeding lines had final late leaf spot ratings similar to those of Georgia-12Y in 2014, whereas in 2015, six of those breeding lines had final leaf spot ratings that were lower than those of Georgia-12Y. Yields were similar for Georgia-12Y and all the breeding lines in the Gibbs Farm trials. Across years and breeding lines at the Lang Farm, the relationship between visual estimates of defoliation and NDVI was described by a two sector piecewise regression with NDVI decreasing more rapidly with increasing defoliation above approximately 89%. The utility of NDVI for spot comparisons among breeding lines appears to be limited to situations where there are differences in defoliation. Georgia-12Y and multiple breeding lines evaluated show potential for use in situations such as organic production where acceptable fungicides available for seed treatment and leaf spot control are limited.

scholarly journals Improved Management Efficacy of Late Leaf Spot on Peanut Through Combined Application of Prothioconazole with Fluxapyroxad and Pyraclostrobin

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 298 ◽  
Author(s):  
Daniel J. Anco ◽  
Justin B. Hiers ◽  
James S. Thomas
Keyword(s):  
South Carolina ◽  
Leaf Spot ◽  
Yield Loss ◽  
Integrated Management ◽  
Commercial Production ◽  
Yield Potential ◽  
Independent Action ◽  
Late Leaf Spot ◽  
Critical Part ◽  
Combined Application

Late leaf spot, caused by Nothopassalora personata, is the most economically important fungal disease affecting peanut foliage in South Carolina and can result in combined management and yield loss costs of greater than 490 dollars/ha. Application of protectant fungicides is a critical part of effective integrated management under commercial production, and their strategic alternation and combination in management programs can provide enhanced control. Trials were conducted in Blackville, SC, from 2017 to 2019 to investigate whether combinations of prothioconazole with fluxapyroxad plus pyraclostrobin could provide more efficacious management of late leaf spot compared to either product alone. Two applications of 0.11 kg/ha prothioconazole with 0.05 kg/ha fluxapyroxad plus 0.1 kg/ha pyraclostrobin resulted in significantly (p < 0.05) less (24% to 42%) peanut canopy defoliation compared to the same number of applications of either product applied individually, with the combined application reflecting significant (p < 0.0202) synergism compared to component products as assessed through independent action methodology. An increased rate of fluxapyroxad plus pyraclostrobin application (0.1 and 0.2 kg/ha, respectively), with 0.16 kg/ha prothioconazole did not improve management relative to their combination at the examined lower rate (p = 0.89). Peanut yield was not adversely affected following combined applications. Cost-effectiveness of this combination depends on the actual disease intensity and yield potential of a given crop.

scholarly journals Evaluation of Improved Valencia Peanut Varieties for Production in Haiti

2020 ◽  
Vol 47 (1) ◽  
pp. 1-8
Author(s):  
A.M. Fulmer ◽  
T.B. Brenneman ◽  
R.C. Kemerait ◽  
R. Macajoux ◽  
D.A. Carroll ◽  
...  
Keyword(s):  
Arachis Hypogaea ◽  
Leaf Spot ◽  
Yield Potential ◽  
Average Increase ◽  
Cercosporidium Personatum ◽  
Central Plateau ◽  
Late Leaf Spot ◽  
Puccinia Arachidis ◽  
Arachis Hypogaea L ◽  
Plot Design

ABSTRACT Late leaf spot (Cercosporidium personatum) and peanut rust (Puccinia arachidis) are the most important diseases of peanut (Arachis hypogaea L.) in Haiti. Traditional Haitian peanut varieties are not only susceptible to these diseases but are also typically grown without benefit of a fungicide program. Five trials were conducted from 2015 to 2017 to evaluate the performance of six Valencia varieties in Quartier-Morin, Haiti (with an additional trial in 2017 at the Central Plateau) with respect to yield, resistance to rust and leaf spot diseases, and response to a fungicide program. A split-plot design with four or six replications was used in these studies. In each, “variety” was the whole plot and presence or absence of a fungicide program was the subplot. Valencia market types 309 Red, 309 Tan, M2, M3, SGV0801 and a local landrace were compared with and without Muscle ADV (tebuconazole + chlorothalonil, Sipcam) (2.3 L/ha) applied at 45, 60 and 75 days after planting (DAP). Final disease ratings (late leaf spot and peanut rust) were assessed approximately 94 DAP and plots were harvested the day following. In all trials, 309 Tan variety had the least amount of leaf spot and rust, but resulted in the lowest yield in four out of five trials, averaging 1727 kg/ha across fungicide treatments. M3, M2 and 309 Red were generally the numerically highest-yielding varieties, averaging 2906, 2864 and 2541 kg/ha across fungicide treatments, respectively, but were not statistically higher than the local Haitian Valencia, averaging 2374 kg/ha. Three fungicide applications during the season significantly increased yields in most trials for all varieties except 309 Tan. The highest and lowest average increase in yield from fungicide was for 309 Red (1126 kg/ha) and 309 Tan (103 kg/ha), respectively. The results from this study conducted over 2 years and 4 seasons document that while resistance to late leaf spot and rust is available in Valencia varieties, yield potential is not directly associated with that resistance. Also, use of fungicide improves yield potential in more susceptible varieties.

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 Evaluation of Rotational Biopesticide Programs for Disease Management in Organic Cucurbit Production

Plant Disease ◽  
2016 ◽  
Vol 100 (11) ◽  
pp. 2226-2233 ◽  
Author(s):  
Sasha C. Marine ◽  
Mason J. Newark ◽  
Robert C. Korir ◽  
Kathryne L. Everts
Keyword(s):  
Disease Management ◽  
Powdery Mildew ◽  
Field Trials ◽  
Management Program ◽  
Organic Production ◽  
Podosphaera Xanthii ◽  
Management Option ◽  
Resistance Development ◽  
Pathogen Populations ◽  
Organically Managed

Downy mildew (Pseudoperonospora cubensis) and powdery mildew (Podosphaera xanthii) are two of the most economically important and widespread cucurbit diseases. Disease management relies primarily on fungicide use, but frequent fungicide applications can lead to the development of resistant pathogen populations. In addition, more vegetables are being produced with organic practices, which prohibit the use of many fungicides. Incorporating biorational products into a disease management program may help mitigate the risk of fungicide resistance development while being compatible with organic production. Field trials were conducted for two years on organically managed land in Maryland with cucumber, muskmelon, pumpkin, and butternut squash to evaluate the efficacy of four biorational products (i.e., Actinovate AG, OxiDate, Regalia, and Serenade Soil) when applied in a rotational program with copper against foliar cucurbit diseases. Generally, all biorational treatments resulted in significantly lower downy and powdery mildew severity compared with the nontreated plants, but the level of disease management was not significantly different than that provided by copper alone. However, Actinovate AG, OxiDate, and Serenade Soil each improved disease management on at least one crop, as compared with copper alone. Rotational programs with biopesticides are a viable disease management option for organic production of field-grown cucurbits in Maryland.

Evaluation of Runner Peanut Cultivars and Advanced Georgia Breeding Lines for Yield and Resistance to Late Leaf Spot Under Three Disease-Management Programs1

1994 ◽  
Vol 21 (1) ◽  
pp. 48-54 ◽  
Author(s):  
F. D. Smith ◽  
T. B. Brenneman ◽  
W. D. Branch ◽  
B. G. Mullinix
Keyword(s):  
Disease Management ◽  
Leaf Spot ◽  
Anastomosis Group ◽  
Yield Potential ◽  
Leaf Spot Disease ◽  
Late Leaf Spot ◽  
Breeding Lines ◽  
Group 4 ◽  
Arachis Hypogaea L ◽  
Peanut Cultivars

Abstract Podyield and resistance to late leaf spot, caused by Cercosporidium personatum (Berk. & M.A. Curtis) Deighton, were evaluated on nine advanced Georgia breeding lines and five cultivars of peanut (Arachis hypogaea L.): Florunner, Georgia Runner, GK-7, Southern Runner, and Sunrunner. Peanuts were grown at Tifton, GA during 1987-1988 under three leaf spot programs using diniconazole at 0.14 kg/ha with Agri-Dex® (0.5% v/v): 1) unsprayed, 2) 28-day, and 3) 14-day spray schedule. Final disease ratings (Florida 1 to 10 scale) were made approximately 1-wk prior to harvest. In unsprayed plots, Southern Runner and GaT-2566 had significantly lower leaf spot disease ratings than Florunner, GK-7, Sunrunner, and Georgia Runner. Across all fungicide treatments, yields of Georgia Runner averaged significantly higher than the four other cultivars and GaT-2566. Average yields were 5111, 4497, 4433, 4404, 4377, and 4022 kg/ha for Georgia Runner, Southern Runner, GK-7, GaT-2566, Sunrunner, and Florunner, respectively. In addition to low yield potential of GaT-2566, it was susceptible to Rhizoctonia limb rot (R. solani Kühn, anastomosis group 4). However, Georgia Runner was found to have moderate tolerance to late leaf spot and excellent yield potential.

scholarly journals Septoria Leaf Spot Reduces Flower Bud Set and Yield Potential of Rabbiteye and Southern Highbush Blueberries

Plant Disease ◽  
2006 ◽  
Vol 90 (1) ◽  
pp. 51-57 ◽  
Author(s):  
P. S. Ojiambo ◽  
H. Scherm ◽  
P. M. Brannen
Keyword(s):  
Disease Severity ◽  
Leaf Spot ◽  
Field Trials ◽  
Fruit Weight ◽  
Early Spring ◽  
Yield Potential ◽  
Flower Bud ◽  
Bud Set ◽  
Southern Highbush ◽  
Septoria Leaf Spot

In field trials on Premier rabbiteye blueberry, individual shoots were selected and tagged in the fall of 2001, 2002, and 2003 to quantify the effects of Septoria leaf spot severity and disease-induced premature defoliation on flower bud set and return yield. Experiments were carried outsimilarly on Bluecrisp southern highbush blueberry using shoots tagged after fruit harvest in the summer of 2002 and 2003. Leaves on the distal 20-cm segments of these shoots were monitored for disease severity (number of spots per leaf) through the remainder of the growing season; at the same time, defoliation (expressed as the proportion of nodes with missing leaves) was recorded for each of the shoot segments. Flower bud set was assessed subsequently in winter or early spring, and berries were harvested as they matured the following summer to determine return yield. For both cultivars, higher flower bud numbers were more likely to occur on shoots with lower disease levels the previous fall (P ≤ 0.0462 based on a Kolmogorov-Smirnov test). The data further showed that flower bud set potential (i.e., the maximum number of buds on shoots within a given disease severity range) decreased linearly as disease severity increased (r2 ≥ 0.926, P ≤ 0.0005). Based on the slope of this relationship, flower bud set potential decreased by one bud per shoot as disease severity the previous fall increased by 18 and 12 spots per leaf for Premier and Bluecrisp, respectively. Relationships between yield and disease variables were similar to those of flower bud numbers and disease, except that the decrease in yield potential (i.e., the maximum fruit weight per shoot within a given disease severity range) was less gradual than for flower bud set potential. On Premier, yield potential dropped markedly and significantly as disease severity the previous fall exceeded about 50 to 60 spots per leaf on average (P < 0.0001 based on a Kruskal-Wallis test). Evidence for such a threshold effect was weaker on Bluecrisp, presumably because of the lower number of data points for this cultivar combined with lower yields due to poor pollination.

2012–2016 On-Farm Evaluation of Fungicide Programs for Peanut Disease Control in Hamilton County, Florida

EDIS ◽  
2017 ◽  
Vol 2017 (4) ◽  
Author(s):  
Keith W. Wynn ◽  
Nicholas S. Dufault ◽  
Rebecca L. Barocco
Keyword(s):  
Plant Pathology ◽  
Disease Control ◽  
Leaf Spot ◽  
Fungal Disease ◽  
White Mold ◽  
Stem Rot ◽  
Late Leaf Spot ◽  
Fact Sheet ◽  
On Farm ◽  
Hamilton County

This ten-page fact sheet includes a summary of various fungicide spray programs for fungal disease control of early leaf spot, late leaf spot, and white mold/stem rot of peanut in 2012-2016 on-farm trials in Hamilton County. Written by K.W. Wynn, N.S. Dufault, and R.L. Barocco and published by the Plant Pathology Department.http://edis.ifas.ufl.edu/pp334

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