scholarly journals Assessment of the Effects of Fertilizer Applications on Gray Leaf Spot and Yield in Maize

Plant Disease ◽  
2002 ◽  
Vol 86 (8) ◽  
pp. 859-866 ◽  
Author(s):  
P. M. Caldwell ◽  
J. M. J. Ward ◽  
N. Miles ◽  
M. D. Laing
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Leaf Spot ◽  
Gray Leaf Spot ◽  
Small Scale ◽  
Grain Yields ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Progress Curve ◽  
Maize Grain

The effects of the application of 0, 60, and 120 kg N ha-1 and of 0, 25, 50, and 150 kg K ha-1 on final disease severity, standardized area under disease progress curve, and grain yield were investigated at Cedara, South Africa, on a maize (Zea mays) hybrid susceptible to gray leaf spot (GLS), caused by Cercospora zeae-maydis. The trial was a randomized 3 × 4 factor design, split for fungicide treatments, and replicated three times. With increased N and K levels, final percent leaf blighting and the standardized area under disease progress curve were higher. In fungicide-treated maize, grain yields increased with increasing levels of N and K, as expected. In non-fungicide-treated maize, grain yield increased significantly with increased levels of N, despite increased disease severity. This was in contrast to small increases in grain yields from non-fungicide-treated maize with increased K levels, which were not significant. This was probably because grain yield response, which should have occurred at higher K applications, was reduced by increased disease severity. The effect of N, P, and K on GLS wasinvestigated at Ahrens. Maize was grown in a 4 × 4 × 4 N-P-K factorial, in a randomized complete block design. Fertilizer was applied at 0, 60, 120, and 180 kg N ha-1, 0, 30, 60, and 120 kg P ha-1, and 0, 50, 100, and 150 kg K ha-1. No fungicides were applied. A single disease assessment at physiological maturity showed that final disease severity increased with increasing levels of N, P, and K. These results have implications for small-scale farmers who are encouraged to fertilize for increased grain yields but may not have the resources to apply fungicide sprays to control fungal diseases.

scholarly journals Potential of Fungal Endophytes to Antagonise Puccinia striiformis Causing Wheat Yellow Rust

2019 ◽  
Author(s):  
Hafiz Arslan Anwaar ◽  
Rashida Perveen ◽  
Muhammad Zeeshan Mansha ◽  
Hafiz Muhammad Aatif ◽  
Zahid Mahmood Sarwar ◽  
...  
Keyword(s):  
Grain Yield ◽  
Disease Severity ◽  
Yellow Rust ◽  
Fungal Endophytes ◽  
Colletotrichum Lindemuthianum ◽  
Wheat Genotypes ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Progress Curve ◽  
Yield Gain

In this study, we evaluated the potential of fungal endophytes to control yellow rust in wheat (Triticum aestivum L.) as endophytes are beneficial microbes and alternate to pesticides for confronting pathogens. The in-vitro efficacy of the fungal endophytes isolated from different desert plants was evaluated and the best four namely Colletotrichum lindemuthianum, Piriformospora indica, Acremonium lolii and Trichoderma viride were selected. Seeds of two susceptible wheat genotypes namely Fareed-06 and Shafaq-06 obtained from screening experiment were inoculated by dipping in four endophytic spore suspensions and were sown using randomized complete block design under factorial arrangement. Data concerning about area under disease progress curve, final disease severity percentage, coefficient of infection,1000- grains weight and grain yield were recorded. Results showed that endophyte P. indica showed significant decrease in final disease severity (FDS) and area under disease progress curve (AUDPC), resultantly 12.2% grain yield gain in rust susceptible wheat genotypes of Fareed-06 and Shafaq-06 followed by the endophytes T. viride, C. lindemuthianum and A. lolii with the grain yield gain of 10.6%, 06.2% and 04.2% respectively. In crux, fungal endophytes are valuable microbes which can be employed to induce tolerance against P. striiformis in yellow rust vulnerable areas for better and sustainable wheat production.

scholarly journals Management of Daylily Rust With Different Fungicides and Fungicide Combinations

2017 ◽  
Vol 18 (3) ◽  
pp. 162-165 ◽  
Author(s):  
Robert S. Emmitt ◽  
James W. Buck
Keyword(s):  
United States ◽  
Disease Management ◽  
Disease Severity ◽  
Low Cost ◽  
Single Application ◽  
Southeast United States ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Progress Curve ◽  
Disease Pressure

Production nurseries and daylily hybridizers in the southeast United States rely on the use of fungicides to manage daylily rust, caused by the fungus Puccinia hemerocallidis. Foliar sprays of pyraclostrobin, flutolanil, tebuconazole, myclobutanil, chlorothalonil, mancozeb, pyraclostrobin + boscalid, flutolanil + tebuconazole, flutolanil + myclobutanil, flutolanil + chlorothalonil, and flutolanil + mancozeb applied on 14-day intervals, and a nontreated control, were evaluated under high disease pressure at three locations in Griffin, GA, in 2015. Tebuconazole or the tebuconazole + flutolanil treatment consistently had the lowest area under the disease progress curve (AUDPC) of the treatments. The addition of flutolanil to chlorothalonil or mancozeb did not improve rust control and no difference in disease severity was observed in any treatment containing contact fungicides on all assessment dates. Single application costs ranged from $10.21 to $95.96 with tebuconazole providing excellent disease management at a relatively low cost per application ($13.90).

scholarly journals Temporal progress of southern rust in maize under different environmental conditions

2003 ◽  
Vol 28 (3) ◽  
pp. 273-278 ◽  
Author(s):  
Cláudia V. Godoy ◽  
Lílian Amorim ◽  
Armando Bergamin Filho ◽  
Herbert P. Silva ◽  
Willian J. Silva ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Disease Severity ◽  
Logistic Model ◽  
Inflection Point ◽  
Gompertz Model ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Progress Curve ◽  
Puccinia Polysora ◽  
The Mean

The progress of the severity of southern rust in maize (Zea mays) caused by Puccinia polysora was quantified in staggered plantings in different geographical areas in Brazil, from October to May, over two years (1995-1996 and 1996-1997). The logistic model, fitted to the data, better described the disease progress curves than the Gompertz model. Four components of the disease progress curves (maximum disease severity; area under the disease progress curve, AUDPC; area under the disease progress curve around the inflection point, AUDPCi; and epidemic rate) were used to compare the epidemics in different areas and at different times of planting. The AUDPC, AUDPCi, and the epidemic rate were analyzed in relation to the weather (temperature, relative humidity, hours of relative humidity >90%, and rainfall) and recorded during the trials. Disease severity reached levels greater than 30% in Piracicaba and Guaíra in the plantings between December and January. Lower values of AUDPC occurred in later plantings at both locations. The epidemic rate was positively correlated (P < 0.05) with the mean daily temperatures and negatively correlated with hours of relative humidity >90%. The AUDPC was not correlated with any weather variable. The AUDPCi was negatively related to both variables connected to humidity, but not to rain. Long periods (mostly >13 h day-1) of relative humidity >90% (that corresponded to leaf wetness) occurred in Castro. Severity of southern rust in maize has always been low in Castro, thus the negative correlations between disease and the two humidity variables.

scholarly journals FIELD INOCULATION TESTS TO QUANTIFY RESISTANCE IN SPINACH TO RACES 3 AND 4 OF DOWNY MILDEW

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 598b-598
Author(s):  
L.P. Brandenberger ◽  
J.C. Correll ◽  
T.E. Morelock ◽  
R.W. McNew
Keyword(s):  
Downy Mildew ◽  
Disease Severity ◽  
Leaf Surface ◽  
Field Inoculation ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Progress Curve

Resistance to race 3 and 4 of downy mildew (Peronospora farinosa f.sp. spinaciae) was examined in separate field inoculation tests. Three Arkansas cultivars and three other commercial spinach cultivars were compared by periodically scoring individual leaves for disease severity 7 to 28 days after inoculation. Leaves were scored on a 0 to 6 scale with 0 = 0% of the leaf surface being covered with sporulation and 6 = 90-100%. Resistance was evaluated by comparing disease ratings on a given day as well as the area under the disease progress curve. Arkansas spinach cultivars exhibited significantly lower disease severity ratings in field inoculation tests for all sample dates for both races 3 and 4 when compared to known susceptible cultivars.

scholarly journals Fungicide Management of Faba Bean Gall (Olpidium viciae) in Ethiopia

2019 ◽  
Vol 7 (7) ◽  
pp. 1075 ◽  
Author(s):  
Wulita Wondwosen Kebede ◽  
Mashilla Dejene W/Michael ◽  
Negussie Tadesse ◽  
Seid Ahmed Kemal
Keyword(s):  
Grain Yield ◽  
Faba Bean ◽  
Natural Infection ◽  
Block Design ◽  
Severity Index ◽  
Northern Ethiopia ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Budget Analysis ◽  
Progress Curve

Various biotic, abiotic and socio-economic factors negatively affect the productivity of the crop. Among these, a new disease known as Faba bean galls (Olpidium viciae) has become a serious threat to faba bean production and productivity in highland areas of central and northern Ethiopia. Thus, field experiment was conducted in Lay Gorebela and Mush to assess the efficacies of fungicides for the management of faba bean gall under natural infection. Six fungicides were evaluated alongside control in randomized complete block design in three replications. Fungicides showed different levels of efficiency at both locations in both seasons. In 2014/15, the highest percent severity index and area under disease progress curve were calculated from control plots at both locations. At Lay Gorebela, higher grain yields were recorded from Metalaxyl 8% + Mancozeb 64% WP and Triadimefon 250 g/L sprayed plots whereas plots sprayed with Metalaxyl 8% + Mancozeb 64% WP gave higher yield at Mush. Similar trends in percent severity index and grain yield were observed with control treatment in 2015/16. Percent severity index and area under disease progress curve were negatively correlated with grain yield and positively correlated with each other at both locations and seasons. Partial budget analysis indicated as Triadimefon 250 g/L and Metalaxyl 8% + Mancozeb 64% WP were cost-effective. The chemical treatment could be used as a short-term control strategy, and a component in integrated management of faba bean galls.

scholarly journals Ramularia leaf spot severity and effects on cotton leaf area and yield1

2016 ◽  
Vol 46 (4) ◽  
pp. 434-441
Author(s):  
João Paulo Ascari ◽  
◽  
Inês Roeder Nogueira Mendes ◽  
Vanessa Costa da Silva ◽  
Dejânia Vieira de Araújo
Keyword(s):  
Leaf Area ◽  
Leaf Spot ◽  
Yield Loss ◽  
Cotton Leaf ◽  
Cotton Yield ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Progress Curve ◽  
Ramularia Leaf Spot ◽  
Upper Third

ABSTRACT Cotton monoculture favors the development of diseases such as ramularia leaf spot, which causes early defoliation and boll rotting, thus decreasing yield. This study aimed at evaluating the severity of ramularia leaf spot and its effects on cotton leaf area and yield. The experiment was conducted in a triple (4 x 3 x 2) factorial design, consisting of four cultivars (FM940GLT, FM944GL, TMG42WS and TMG43WS), three thirds of the plant (lower, middle and upper) and two management conditions (with and without fungicide application). To the variable area under the disease progress curve, the lowest values were observed in the upper third of the TMG42WS and TMG43WS cultivars, with the lower and middle thirds presenting the highest severity. The condition managed with fungicide and the upper third showed the lowest values for area under the disease progress curve. The leaf area was negatively affected by the ramularia leaf spot. Concerning the seed and fiber yields, the highest averages were observed for the middle third and the condition managed with fungicide. There was no statistical difference for cotton yield loss.

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

1988 ◽  
Vol 15 (1) ◽  
pp. 39-43 ◽  
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.

scholarly journals Control of Asian soybean rust with mancozeb, a multi-site fungicide

2015 ◽  
Vol 41 (1) ◽  
pp. 64-67 ◽  
Author(s):  
Luís Henrique Carregal Pereira da Silva ◽  
Hercules Diniz Campos ◽  
Juliana Resende Campos Silva ◽  
Erlei Melo Reis
Keyword(s):  
Grain Yield ◽  
Analysis Of Variance ◽  
Soybean Rust ◽  
Phakopsora Pachyrhizi ◽  
Disease Progress Curve ◽  
Disease Progress ◽  
Asian Soybean Rust ◽  
Progress Curve ◽  
Fungicide Mixtures ◽  
Rust Severity

An experiment conducted in the field the action of mancozeb, a fungicide of multi-site action was tested, to control soybean rust caused by Phakopsora pachyrhizi. Its performance was compared to that of the mixture cyproconazole (DMI) + azoxystrobin (QoI). The soybean cultivar NA 7337 RR was used with a population of 400,000 plants/ha cultivated in 20m2 plots. Treatments consisted of mancozeb levels (1.5 and 2.0 kg/ha) applied four, six and eight times. The DMI + QoI mixture was applied three times at 0.3 L/ha + Nimbus. Rust severity was assessed six times in the plots and data were integrated as the area under the disease progress curve (AUDPC). The plots were harvested and grain yield was expressed as kg/ha. Data on AUDPC and yield were subjected to analysis of variance and means compared according to Turkey's test (p = 0.005). Treatments with mancozeb were superior to DMI + QoI mixture both for rust control and grain yield. Four applications of 2.0 k/ha mancozeb were more efficient than three applications of the mixture used as standard. Mancozeb has the potential to be added to fungicide mixtures in the establishment of soybean rust anti-resistance strategy.

scholarly journals EVALUATION OF MAIZE HYBRIDS TOLERANT TO PHAEOSPHAERIA LEAF SPOT, GRAY LEAF SPOT AND COMMON RUST AND YIELD

2017 ◽  
Vol 16 (1) ◽  
pp. 72
Author(s):  
RENATO BARBOSA CAMARGOS ◽  
JOÃO CANDIDO DE SOUZA ◽  
EDUARDO ALVES ◽  
CARLOS EDUARDO CAIXETA DE CASTRO ◽  
PAULO EDUARDO RODRIGUES PRADO ◽  
...  
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Leaf Spot ◽  
Zea Mays L ◽  
Gray Leaf Spot ◽  
Maize Hybrids ◽  
Progress Curve ◽  
Lattice Arrangement ◽  
Plant Emergence ◽  
Set Up

 ABSTRACT - The objectives of this study were to identify maize hybrids which have high grain yield and resistance to Phaeosphaeria leaf spot, gray leaf spot and common rust, as well as to estimate the most efficient period for measuring the reaction of the hybrids to the pathogens. Two experiments were set up in Lavras, MG, Brazil, assessing 30 hybrids in the season of 2011/2012. The experimental design was a 6 x 5 lattice arrangement with three replications. Grain yield was evaluated and five assessments of disease severity were performed at ten-day intervals as of 60 days after maize emergence. After that, the area under the disease progress curve (AUDPC) and the Spearman correlations between the diseases and the various assessment periods for each disease were estimated. It was found that the hybrids GNZ9626 PRO and GNZ9501 PRO have high grain yield and a satisfactory level of resistance to Phaeosphaeria leaf spot, gray leaf and common rust, and that assessment of the level of resistance to these diseases should be performed in the period from 80 to 100 days after plant emergence, which provides results similar to AUDPC.Keywords: Zea mays L., Leaf diseases, Genetic resistance.AVALIAÇÃO DE HÍBRIDOS DE MILHO À MANCHA BRANCA, CERCOSPORIOSE E FERRUGEM COMUM E À PRODUTIVIDADERESUMO - Os objetivos deste trabalho foram identificar híbridos de milho que apresentem alta produtividade de grãos e resistência à mancha-branca, cercosporiose e ferrugem comum, bem como estimar a época de avaliação mais eficiente para mensurar a reação dos híbridos aos patógenos causadores dessas doenças. Para isso, foram instalados dois experimentos no município de Lavras, MG e avaliados 30 híbridos no ano agrícola de 2011/2012. O delineamento experimental utilizado foi o látice 6 x 5 com três repetições. Foi avaliada a produtividade de grãos e realizadas cinco avaliações da severidade dessas enfermidades, em intervalos de 10 dias, a partir de 60 dias da emergência das plantas. Posteriormente, estimou-se a área abaixo da curva de progresso das doenças (AACPD) e a correlação de Sperman entre as mesmas com as diversas épocas de avaliação de cada doença. Constatou-se que os híbridos GNZ9501 PRO e GNZ9626 PRO apresentam alta produtividade de grãos e satisfatório nível de resistência à mancha-branca, cercosporiose e ferrugem comum e que para a avaliação do nível de resistência a essas enfermidades deve-se optar pela avaliação no período que compreende 80 a 100 dias após a emergência das plantas, o qual fornece resultados semelhantes à AACPD.Palavras-chave: Zea mays L., Doenças foliares, Resistência genética.

Sign in / Sign up

Export Citation Format

Share Document