Fungicide efficacy of nanocrystal-based formulations against peanut smut

2020 ◽  
pp. 105522
Author(s):  
Boris X. Camiletti ◽  
Juan A. Paredes ◽  
Joaquín H. Monguillot ◽  
Nelson R. Grosso ◽  
Alejandro M. Rago
Keyword(s):  
Fungicide Efficacy

scholarly journals Effects of Integrating Cultivar Resistance and Fungicide Application on Fusarium Head Blight and Deoxynivalenol in Winter Wheat

Plant Disease ◽  
2011 ◽  
Vol 95 (5) ◽  
pp. 554-560 ◽  
Author(s):  
Stephen N. Wegulo ◽  
William W. Bockus ◽  
John Hernandez Nopsa ◽  
Erick D. De Wolf ◽  
Kent M. Eskridge ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Fusarium Head Blight ◽  
Field Experiments ◽  
Economic Losses ◽  
Cultivar Resistance ◽  
Head Blight ◽  
Resistant Cultivars ◽  
Fungicide Application ◽  
Fungicide Efficacy ◽  
Moderately Resistant

Fusarium head blight (FHB) or scab, incited by Fusarium graminearum, can cause significant economic losses in small grain production. Five field experiments were conducted from 2007 to 2009 to determine the effects on FHB and the associated mycotoxin deoxynivalenol (DON) of integrating winter wheat cultivar resistance and fungicide application. Other variables measured were yield and the percentage of Fusarium-damaged kernels (FDK). The fungicides prothioconazole + tebuconazole (formulated as Prosaro 421 SC) were applied at the rate of 0.475 liters/ha, or not applied, to three cultivars (experiments 1 to 3) or six cultivars (experiments 4 and 5) differing in their levels of resistance to FHB and DON accumulation. The effect of cultivar on FHB index was highly significant (P < 0.0001) in all five experiments. Under the highest FHB intensity and no fungicide application, the moderately resistant cultivars Harry, Heyne, Roane, and Truman had less severe FHB than the susceptible cultivars 2137, Jagalene, Overley, and Tomahawk (indices of 30 to 46% and 78 to 99%, respectively). Percent fungicide efficacy in reducing index and DON was greater in moderately resistant than in susceptible cultivars. Yield was negatively correlated with index, with FDK, and with DON, whereas index was positively correlated with FDK and with DON, and FDK and DON were positively correlated. Correlation between index and DON, index and FDK, and FDK and DON was stronger in susceptible than in moderately resistant cultivars, whereas the negative correlation between yield and FDK and yield and DON was stronger in moderately resistant than in susceptible cultivars. Overall, the strongest correlation was between index and DON (0.74 ≤ R ≤ 0.88, P ≤ 0.05). The results from this study indicate that fungicide efficacy in reducing FHB and DON was greater in moderately resistant cultivars than in susceptible ones. This shows that integrating cultivar resistance with fungicide application can be an effective strategy for management of FHB and DON in winter wheat.

scholarly journals Detection of smut mycelia in apical meristems of sugarcane buds

1969 ◽  
Vol 75 (3) ◽  
pp. 281-286
Author(s):  
Rodrigo Echávez-Badel
Keyword(s):  
Apical Meristem ◽  
Staining Method ◽  
Saccharum Officinarum ◽  
Seed Certification ◽  
Apical Meristems ◽  
Sugarcane Varieties ◽  
Certification Programs ◽  
Ustilago Scitaminea ◽  
Fungicide Efficacy ◽  
Nursery Field

Two tests were conducted to detect the fungal mycelia of Ustilago scitaminea Syd. in apical meristems of sugarcane (Saccharum officinarum L.) buds. In the first test six varieties were selected from infected sugarcane fields, and in the second test three varieties obtained from a nursery field were artificially inoculated with the fungus. Sugarcane plants artificially inoculated with U. scitaminea were used as checks in the first test. Growing points were removed from the plant cane and stained for 4 to 18 h by using Sinha's technique. Microscopic observations indicated the absence and presence of smut mycelia in the apical meristem buds of healthy and infected sugarcane varieties. The staining method of growing point nodal buds can be useful for indicating fungicide efficacy in controlling sugarcane smut, and for sugarcane seed certification programs.

scholarly journals Efficacy of Variable Tetraconazole Rates Against Cercospora beticola Isolates with Differing In Vitro Sensitivities to DMI Fungicides

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1749-1756 ◽  
Author(s):  
Melvin D. Bolton ◽  
Viviana Rivera-Varas ◽  
Luis E. del Río Mendoza ◽  
Mohamed F. R. Khan ◽  
Gary A. Secor
Keyword(s):  
Sugar Beet ◽  
Disease Severity ◽  
Cercospora Beticola ◽  
In Planta ◽  
Sensitivity Testing ◽  
In Vitro Sensitivity ◽  
Wide Range ◽  
Fungicide Efficacy ◽  
Dmi Fungicides

Cercospora leaf spot (CLS) of sugar beet is caused by the fungus Cercospora beticola. CLS management practices include the application of the sterol demethylation inhibitor (DMI) fungicides tetraconazole, difenoconazole, and prothioconazole. Evaluating resistance to DMIs is a major focus for CLS fungicide resistance management. Isolates were collected in 1997 and 1998 (baseline sensitivity to tetraconazole, prothioconazole, or difenoconazole) and 2007 through 2010 from the major sugar-beet-growing regions of Minnesota and North Dakota and assessed for in vitro sensitivity to two or three DMI fungicides. Most (47%) isolates collected in 1997–98 exhibited 50% effective concentration (EC50) values for tetraconazole of <0.01 μg ml–1, whereas no isolates could be found in this EC50 range in 2010. Since 2007, annual median and mean tetraconazole EC50 values have generally been increasing, and the frequency of isolates with EC50 values >0.11 μg ml–1 increased from 2008 to 2010. In contrast, the frequency of isolates with EC50 values for prothioconazole of >1.0 μg ml–1 has been decreasing since 2007. Annual median difenoconazole EC50 values appears to be stable, although annual mean EC50 values generally have been increasing for this fungicide. Although EC50 values are important for gauging fungicide sensitivity trends, a rigorous comparison of the relationship between in vitro EC50 values and loss of fungicide efficacy in planta has not been conducted for C. beticola. To explore this, 12 isolates exhibiting a wide range of tetraconazole EC50 values were inoculated to sugar beet but no tetraconazole was applied. No relationship was found between isolate EC50 value and disease severity. To assess whether EC50 values are related to fungicide efficacy in planta, sugar beet plants were sprayed with various dilutions of Eminent, the commercial formulation of tetraconazole, and subsequently inoculated with isolates that exhibited very low, medium, or high tetraconazole EC50 values. The high EC50 isolate caused significantly more disease than isolates with medium or very low EC50 values at the field application rate and most reduced rates. Because in vitro sensitivity testing is typically carried out with the active ingredient of the commercial fungicide, we investigated whether loss of disease control was the same for tetraconazole as for the commercial product Eminent. The high EC50 isolate caused more disease on plants treated with tetraconazole than Eminent but disease severity was not different between plants inoculated with the very low EC50 isolate.

Evaluation of fungicide efficacy on sunflower rust (Puccinia helianthi) on oilseed and confection sunflower

2021 ◽  
Author(s):  
Brandt Berghuis ◽  
Andrew Friskop ◽  
Michelle Gilley ◽  
Jessica Halvorson ◽  
Bryan Hansen ◽  
...  
Keyword(s):  
Great Plains ◽  
Field Experiments ◽  
Field Trials ◽  
Northern Great Plains ◽  
Puccinia Helianthi ◽  
Action Threshold ◽  
The Us ◽  
Fungicide Efficacy ◽  
Rust Severity ◽  
Important Disease

Sunflower rust, caused by Puccinia helianthi, is an economically and globally important disease of sunflower. Two types of sunflowers are produced in the US Northern Great Plains; the oilseed type and the confection type. Although approximately 80% of the acreage in this region is planted as the oilseed type sunflower, fungicide efficacy and timing studies have been conducted primarily on the more rust-susceptible confection type. A total of ten sunflower rust efficacy field experiments were conducted on oilseed type and confectionary type hybrid trials from 2016-2018. Eleven fungicides from three FRAC groups were evaluated for efficacy and protection of yield. Severity differences among fungicide treatments were identified in both confection and oilseed type sunflower trials. A combined analysis of all confection field trials (five) indicated that rust severity was lower in all fungicide treatments as compared to the non-treated control. Despite rust severity levels below the fungicide action threshold for confection sunflower, seven of the eleven fungicide treatments had yield higher than the non-treated control. In oilseed trials, rust severity was lower in all fungicide treatments as compared to the non-treated control, similar to the findings of the confection type. Rust severity was too low to detect yield differences in oilseed trials. Additional work is needed to elucidate yield-loss potential on oilseed type sunflower and refine the fungicide action threshold on confection type sunflower.

scholarly journals Night Spraying Peanut Fungicides I. Extended Fungicide Residual and Integrated Disease Management

Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 676-682 ◽  
Author(s):  
J. Augusto ◽  
T. B. Brenneman ◽  
A. K. Culbreath ◽  
P. Sumner
Keyword(s):  
Disease Management ◽  
Chemical Control ◽  
Sclerotium Rolfsii ◽  
Residual Activity ◽  
Field Trials ◽  
Stem Rot ◽  
Integrated Disease Management ◽  
Cercospora Arachidicola ◽  
Puccinia Arachidis ◽  
Fungicide Efficacy

The efficacy of chemical control of stem rot (caused by Sclerotium rolfsii) of peanut (Arachis hypogaea) relies partially on increasing deposition and residual activity in the lower canopy. Tebuconazole (0.21 kg a.i./ha, four applications) and azoxystrobin (0.31 kg a.i./ha, two applications) were each applied on peanut plants in daylight or at night, when leaves were folded, in two Tifton, GA, field trials in 2007. Both timings of each fungicide provided similar control of early leaf spot (caused by Cercospora arachidicola). Night applications of azoxystrobin and tebuconazole reduced stem rot at digging and increased yield compared with day applications. Night applications of tebuconazole were also tested in Nicaragua from 2005 to 2007. Peanut plants had less stem rot, similar levels of rust (caused by Puccinia arachidis), and higher yield with night applications than with day applications. Residual activity of azoxystrobin and tebuconazole were improved on the bottom shaded leaves (on which fungicides would be better deposited with night application) compared with top, sun-exposed leaves (where most fungicide would be deposited with a day application) according to a bioassay with S. rolfsii. Increased fungicide residual activity within the bottom canopy may increase fungicide efficacy on stem rot and augment peanut yield.

Quantitative review of fungicide efficacy trials for managing soybean rust in Brazil

2009 ◽  
Vol 28 (9) ◽  
pp. 774-782 ◽  
Author(s):  
H. Scherm ◽  
R.S.C. Christiano ◽  
P.D. Esker ◽  
E.M. Del Ponte ◽  
C.V. Godoy
Keyword(s):  
Soybean Rust ◽  
Quantitative Review ◽  
Efficacy Trials ◽  
Fungicide Efficacy
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