Journal articles on the topic 'Fungicide timing'
To see the other types of publications on this topic, follow the link: Fungicide timing.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Fungicide timing.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Woodward, J. E., T. B. Brenneman, and B. G. Mullinix. "Irrigation Timing Impacts the Efficacy of Foliar-Applied Fungicides Toward Foliar and Soilborne Pathogens of Peanut." Plant Disease 96, no. 12 (December 2012): 1785–90. http://dx.doi.org/10.1094/pdis-01-12-0042-re.
Full textAbstract:
Fungicides not reaching target organisms result in decreased disease control. In the southeastern United States, foliar-applied fungicides are routinely used to manage peanut (Arachis hypogaea) diseases. Irrigation is often applied to wash fungicides from treated foliage to obtain maximum control of diseases caused by soilborne pathogens. Administering irrigation before fungicide residues have dried may adversely impact foliar disease control. A microplot study was conducted in 2003, 2004, and 2005 to evaluate the redistribution of azoxystrobin, tebuconazole, and flutolanil plus chlorothalonil following different irrigation timings. Standard fungicide regimes were subjected to 1.3-cm of irrigation 0, 6, 12, 24, 48, or 96 h after application, and a nonirrigated control was included. Microplots not receiving irrigation were covered while irrigation treatments were administered. Irrigation timing was significant for the number of early leaf spot (Cercospora arachidicola) lesions per leaf. Leaf spot was more severe when irrigation was administered immediately following fungicide applications, and was significantly reduced with a 6- and 12-h delay prior to an irrigation event, whereas maximum control was obtained when irrigation was delayed for 24 h or later. To further quantify fungicide residue distribution, Sclerotium rolfsii was used to bioassay foliage and pods. Lesion development on leaflets, which was greater for earlier irrigation timings, did not differ for the 12-h and later timings and was generally similar to the nonirrigated controls. Pod colonization for all fungicides increased according to a quadratic function of irrigation timing, with the least colonization occurring at the 0-h timing. Colonization of pods treated with azoxystrobin was similar for all irrigation timings; whereas, suppression was greatest for tebuconazole at earlier irrigation timings. This study demonstrates that irrigation can be used to redistribute fungicides applied to peanut foliage to improve control of soilborne pathogens but administering irrigation within 24 h may decrease leaf spot control.
2
Waliyar, F., Moustapha Adamou, and Aoua Traoré. "Rational Use of Fungicide Applications to Maximize Peanut Yield Under Foliar Disease Pressure in West Africa." Plant Disease 84, no. 11 (November 2000): 1203–11. http://dx.doi.org/10.1094/pdis.2000.84.11.1203.
Full textAbstract:
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.
3
Augusto, J., and T. B. Brenneman. "Implications of fungicide application timing and post-spray irrigation on disease control and peanut yield." Peanut Science 38, no. 1 (January 1, 2011): 48–56. http://dx.doi.org/10.3146/ps10-11.1.
Full textAbstract:
Abstract Applying fungicides at night when the leaves are folded and using irrigation water after application have both been shown to increase deposition of fungicides in the lower plant canopy, improve control of stem rot (caused by Sclerotium rolfsii), and increase peanut (Arachis hypogaea) yield. To evaluate the interactive effects of these two practices, four applications of a protectant fungicide, chlorothalonil (1.26 kg a.i./ha), or a systemic, prothioconazole + tebuconazole (0.23 kg a.i./ha), tebuconazole (0.21 kg a.i./ha), flutolanil + propiconazole (0.45 kg a.i./ha), pyraclostrobin (0.21 kg a.i./ha), or two applications of a systemic, fluoxastrobin (0.17 kg a.i./ha) or azoxystrobin (0.31 kg a.i./ha) were sprayed either at night (3 a.m. to 5 a.m., when peanut leaves were folded) or during daylight (10 a.m. to 12 p.m., when peanut leaves were unfolded). Fungicides were applied as sub-subplots and night and day fungicide application timings as subplots in a split-split plot design with post-spray irrigation and nonpost-spray irrigation as whole plots to evaluate disease control and peanut yield in 2008 and 2009. In 2008, leaf spot intensity (early leaf spot caused by Cercospora arachidicola) was low and disease control was similar regardless of application timing or fungicide across post-spray irrigation treatments. In 2009, leaf spot was severe and disease control for night and day applications of a systemic fungicide was similar across post-spray irrigation, but pyraclostrobin and prothioconazole + tebuconazole had the lowest ratings. Interaction of fungicide, application timing and post-spray irrigation was significant for stem rot and yield. Night application of prothioconazole + tebuconazole, flutolanil + propiconazole or pyraclostrobin showed the most increase in stem rot control and yield compared with day application among the evaluated fungicides, but the positive effects on stem rot control and yield were minimal with post-spray irrigation. The effects of application timing and post-spray irrigation on fungicide efficacy were not the same for all fungicides.
4
Evin, Bryn, Scott Meyer, Casey Schuh, Sam Haugen, Jessica Halvorson, Venkata Chapara, Amanda Arens, and Andrew Friskop. "Management of Leaf Rust and Stripe Rust in Hard Red Spring Wheat at Different Timings of Disease Onset." Plant Health Progress 21, no. 4 (January 1, 2020): 306–11. http://dx.doi.org/10.1094/php-06-20-0055-rs.
Full textAbstract:
Stripe rust (Puccinia striiformis f. sp. tritici) and leaf rust (Puccinia triticina) can cause significant yield reductions to hard red spring wheat (HRSW) in North Dakota (ND). The use of host resistance and fungicides can successfully manage this disease. However, the combination of them may not be appropriate every year. From 2016 to 2018, fungicide timing by cultivar experiments were conducted to update recommendations for rust management. Experiments were designed in a randomized complete block with a split-plot arrangement. Main plots included three HRSW cultivars that were moderately resistant, moderately susceptible, and susceptible. Subplots included the fungicide timings of Feekes 9, Feekes 10.5.1, a sequential application, and a nontreated control. Field experiments were categorized into three environments depending on rust onset and disease progress. When rust was detected at early heading, the susceptible cultivar benefited from all fungicide application timings. The detection of rust at tillering leaf stages suggested that fungicide treatments statistically lowered disease and in most cases had statistically higher yield, regardless of host resistance. These results suggest that the benefit from a fungicide application to manage leaf rust and stripe rust is highly influenced by the timing of disease onset and level of host resistance. Results will improve fungicide suggestions for HRSW producers in ND.
5
Friskop, Andrew J., Thomas J. Gulya, Scott A. Halley, Blaine G. Schatz, Joel P. Schaefer, James G. Jordahl, Scott M. Meyer, Kevin W. Misek, Paul Hendrickson, and Samuel G. Markell. "Effect of Fungicide and Timing of Application on Management of Sunflower Rust." Plant Disease 99, no. 9 (September 2015): 1210–15. http://dx.doi.org/10.1094/pdis-10-14-1036-re.
Full textAbstract:
Sunflower rust is an important yield-limiting disease in sunflower production in the Great Plains of the United States. Rust severity and incidence have increased between 2002 and 2011, and genetic resistance is limited in most commercial hybrids, particularly the high-value confectionary market type. Although fungicides are available for rust management in the United States, management recommendations are insufficient. Specifically, efficacy and timing data are very limited for fungicides in FRAC groups 7 and 11. Seventeen fungicide efficacy and timing trials were conducted between 2008 and 2011 in North Dakota. Timings evaluated across the four years included single or multiple applications at growth stages (GS): GS V8-V12 (late vegetative), GS R1 (terminal bud formation), GS R3-4 (elongation of bud), GS R5 (flowering), and GS R6 (completion of flowering). With few exceptions, fungicide applications of DMIs and QoIs controlled disease greater than SDHI fungicides. Fungicide applications made at R5, either singly or in combination, consistently resulted in greater disease control. A negative correlation (r = −0.7756) between disease control and yield was observed, resulting in a yield reduction of 6.6% for every 1% increase in disease severity.
6
Warneke, Brent, Lindsey D. Thiessen, and Walter F. Mahaffee. "Effect of Fungicide Mobility and Application Timing on the Management of Grape Powdery Mildew." Plant Disease 104, no. 4 (April 2020): 1167–74. http://dx.doi.org/10.1094/pdis-06-19-1285-re.
Full textAbstract:
Grape powdery mildew (GPM) fungicide programs consist of 5 to 15 applications, depending on region or market, in an attempt to achieve the high fruit quality standards demanded by the market. Understanding how fungicides redistribute and targeting redistributing fungicide to critical crop phenological stages could improve fungicide protection of grape clusters. This study evaluated fungicide redistribution in grapevines from major fungicide groups labeled for GPM control. Translaminar and xylem redistribution was examined by placing fungicide-impregnated filter disks on the adaxial or abaxial leaf surface of detached leaves for 10 min and then incubating for 48 h before inoculating the abaxial surface with conidia. Vapor redistribution used Teflon disks sprayed with fungicides and placed on the abaxial leaf surface of detached leaves 48 h before inoculation. Disease development was rated 10 days later. Translaminar movement through calyptra was tested using flowering potted vines. All fungicides tested redistributed through at least one mechanism. Fungicide timing at critical phenological stages (early, mid, and late bloom) was assessed in small plots of cultivar Pinot noir vines. The application of trifloxystrobin, quinoxyfen, or fluopyram at different bloom stages showed that applications initiated at end of bloom resulted in the lowest berry infection probabilities of 0.073, 0.097, and 0.020, respectively. The results of this study suggest that integrating two carefully timed applications of redistributing fungicides initiated at end of bloom into a fungicide program may be an effective strategy for wine grape growers in western Oregon to produce fruit with low GPM infection.
7
Gillard, C. L., N. K. Ranatunga, and R. L. Conner. "The effect of foliar fungicide application timing on the control of dry bean anthracnose." Canadian Journal of Plant Science 92, no. 1 (January 2012): 109–18. http://dx.doi.org/10.4141/cjps2010-018.
Full textAbstract:
Gillard, C. L., Ranatunga, N. K. and Conner, R. L. 2012. The effect of foliar fungicide application timing on the control of dry bean anthracnose. Can. J. Plant Sci. 92: 109–118. Anthracnose caused by Colletotrichum lindemuthianum is a major disease of dry bean (Phaseolus vulgaris L.), reducing seed quality and yield. A study carried out in 2005 and 2006 at Exeter, ON, and at Morden, MB, determined that a sequential application of fungicide at the correct time is crucial for the effective management of the disease. The effect of the fungicides azoxystrobin and pyraclostrobin at four single foliar application timings at 5th trifoliolate (A), 1st flower (B), full flower (C) and 10 d after full flower (D) and at three sequential timings (A+C, B+C, and B+D) were evaluated under low and high disease pressure conditions. Data were collected on leaf vein and pod infection, plant maturity, dockage, pick, seed weight, yield and return on investment. Results were analyzed using analysis of variance (ANOVA) and contrast comparisons were carried out for various treatment combinations. Differences between the two fungicides for leaf symptoms were not apparent under low disease pressure, but occurred early in plant development under high disease pressure. Pyraclostrobin-treated plots produced a higher yield under high disease pressure and better quality seeds at both high and low disease pressure conditions. A single fungicide application at the A timing gave higher yield under low disease pressure, while timings B and C gave a higher yield under high disease pressure. A sequential application often provided greater anthracnose control and improved yield and seed quality, compared with single application timings. For the sequential application timings, the highest yields occurred at the A+C timing under low disease pressure, and at the A+C or B+C timing under high disease pressure.
8
Thiessen, L. D., T. M. Neill, and W. F. Mahaffee. "Timing Fungicide Application Intervals Based on Airborne Erysiphe necator Concentrations." Plant Disease 101, no. 7 (July 2017): 1246–52. http://dx.doi.org/10.1094/pdis-12-16-1727-re.
Full textAbstract:
Management of grape powdery mildew (Erysiphe necator) and other polycyclic diseases relies on numerous fungicide applications that follow calendar or model-based application intervals, both of which assume that inoculum is always present. Quantitative molecular assays have been previously developed to initiate fungicide applications, and could be used to optimize fungicide application intervals throughout the growing season based on inoculum concentration. Airborne inoculum samplers were placed at one research and six commercial vineyards in the Willamette Valley of Oregon. Fungicide applications in all plots were initiated at the first detection of E. necator inoculum, and all subsequent fungicide application intervals were made based the grower’ standard calendar program or based on inoculum concentration. In adjusted-interval plots, fungicides were applied at the shortest labeled application interval when >10 spores were detected and the longest labeled application interval when <10 spores were detected. Fungicide applications in control plots consisted of the growers’ standard management practice. An average of 2.3 fewer fungicide applications in 2013 and 1.6 fewer fungicide applications in 2014 were used in the adjusted fungicide application intervals treatment in grower fields without significant differences in berry or leaf disease incidence between treatments.
9
Twizeyimana, M., and G. L. Hartman. "Sensitivity of Phakopsora pachyrhizi Isolates to Fungicides and Reduction of Fungal Infection Based on Fungicide and Timing of Application." Plant Disease 101, no. 1 (January 2017): 121–28. http://dx.doi.org/10.1094/pdis-04-16-0552-re.
Full textAbstract:
Soybean rust (SBR), caused by Phakopsora pachyrhizi, is a damaging foliar fungal disease in many soybean-growing areas of the world. Strategies to manage SBR include the use of foliar fungicides. Fungicide types, the rate of product application, and the number and timing of applications are critical components for successful rust management. The objectives of this study were to determine i) the sensitivity of P. pachyrhizi isolates collected in the U.S. to a range of fungicides and ii) the reduction of fungal infection based on fungicide type and timing of applications on soybean. There were differences (P < 0.05) in effective concentration (EC50) values among the fungicides tested. Azoxystrobin had low EC50 values for both urediniospore germination and fungal sporulation on inoculated leaflets. There were differences (P < 0.05) in fungal sporulation for application times, fungicide treatments, and their interaction when the fungus was inoculated on plants. All application times and nearly all fungicide treatments reduced (α = 0.05) fungal infection compared with the nonfungicide control. Information on fungicide sensitivity of P. pachyrhizi isolates and the preventive and curative effects of different fungicides are important in the management of SBR.
10
Luna, Martha P. Romero, and Kiersten A. Wise. "Timing and Efficacy of Fungicide Applications for Diplodia Ear Rot Management in Corn." Plant Health Progress 16, no. 3 (January 2015): 123–31. http://dx.doi.org/10.1094/php-rs-15-0010.
Full textAbstract:
Diplodia ear rot, a corn (Zea mays L.) disease caused by the fungus Stenocarpella maydis (Berk.) B. Sutton, has been a persistent ear rot across the United States. Management options are currently limited. Field trials conducted under inoculated and non-inoculated conditions were established at two locations in Indiana from 2011 to 2013 to test the fungicides azoxystrobin plus propiconazole and prothioconazole against Diplodia ear rot. Fungicides were applied at three individual growth stages during each year. Fungicides did not consistently reduce Diplodia ear rot compared to non-fungicide-treated controls in any year. Applications also did not consistently increase yield at any timing under inoculated and non-inoculated plots compared with the non-fungicidetreated control. Fungicides were tested in an in vitro assay to determine the effective fungicide concentration at which 50% of mycelial growth or conidial germination of S. maydis was inhibited (EC50). Propiconazole and prothioconazole EC50 values indicated efficacy in reducing fungal growth under controlled conditions; however, current fungicide application methods and plant barriers to fungicide contact with the pathogen may prevent these products from effectively reducing Diplodia ear rot in a field setting. Accepted for publication 23 August 2015. Published 1 September 2015
11
González-Domínguez, Elisa, Pierluigi Meriggi, Matteo Ruggeri, and Vittorio Rossi. "Efficacy of Fungicides against Fusarium Head Blight Depends on the Timing Relative to Infection Rather than on Wheat Growth Stage." Agronomy 11, no. 8 (August 1, 2021): 1549. http://dx.doi.org/10.3390/agronomy11081549.
Full textAbstract:
Fungicides used to control Fusarium head blight (FHB) are commonly applied at the wheat growth stage considered to be most susceptible, i.e., anthesis. We compared the efficacy of the most commonly used fungicide groups that were applied following two strategies: (i) at pre-defined growth stages, from the first half of heading to the end of flowering (experiment 1, in 2013 to 2015), or (ii) based on timing of infection by F. graminearum, specifically at 10, 7, 4, or 1 day before, or 3 or 5 days after artificial inoculation of the fungus (experiment 2, in 2017 and 2018). Fungicide efficacy was evaluated in terms of FHB incidence, FHB severity, and DON contamination by using generalised mixed models. In experiment 1, all fungicide groups reduced FHB severity and DON but only by <50% compared to an untreated control, with no differences among fungicides or growth stages at time of application. In experiment 2, the efficacy of fungicides was higher for applications at 1 or 4 days before inoculation than at 7 or 10 days before or 3 or 5 days after inoculation, with differences among fungicide groups. Based on our results, the timing of fungicide application for FHB control should be based on the time of F. graminearum infection rather than on wheat phenology.
12
Miller, G. L., M. D. Soika, and L. P. Tredway. "Evaluation of Preventive Fungicide Applications for Fairy Ring Control in Golf Putting Greens and In Vitro Sensitivity of Fairy Ring Species to Fungicides." Plant Disease 96, no. 7 (July 2012): 1001–7. http://dx.doi.org/10.1094/pdis-09-11-0779-re.
Full textAbstract:
Fairy ring species induce symptoms on putting greens mostly indirectly, by modifying the soil physical or chemical properties. Therefore, preventive rather than curative fungicide applications may be more effective in managing fairy ring. Two field experiments were conducted on a creeping bentgrass research green to evaluate fairy ring control from preventive fungicide applications. A 3-year study investigated the optimal rate and soil temperature-based timing of a preventive application of triadimefon and tebuconazole. A 2-year study evaluated the impact of irrigation timing and fungicide + surfactant tank mixtures on the efficacy of preventive applications of triadimefon and triticonazole. Fungicide-treated plots in both studies exhibited less fairy ring severity than untreated plots. Data suggest that a 5-day average soil temperature range of 13 to 16°C may be suitable for initiating preventive applications. Symptoms occurred earlier in plots treated with a surfactant tank mix than in those treated with fungicide alone. Irrigation timing had no effect on fungicide performance. The sensitivity of 16 isolates representing major fairy ring species to flutolanil, propiconazole, tebuconazole, triadimefon, and triticonazole was determined with a mycelial growth assay. No significant differences in fungicide sensitivity were detected among species. Isolates had significantly higher 50% effective concentration values for triadimefon than for the other fungicides tested.
13
OLESEN, J. E., L. N. JØRGENSEN, J. PETERSEN, and J. V. MORTENSEN. "Effects of rate and timing of nitrogen fertilizer on disease control by fungicides in winter wheat. 1. Grain yield and foliar disease control." Journal of Agricultural Science 140, no. 1 (February 2003): 1–13. http://dx.doi.org/10.1017/s0021859602002885.
Full textAbstract:
The effects of nitrogen (N) rate and timing on need for fungicide application in winter wheat (Triticum aestivum) were investigated in 3 years of field experiments on loamy sand soils in Denmark. A two-factor completely randomized experimental design was used, comprising seven combinations of different N fertilizer rates and application times, and five doses of fungicide (co-formulation propiconazole and fenpropimorph). Two different varieties of winter wheat with high susceptibility to powdery mildew (Blumeria graminis) were used, Florida in the first season and Pepital in the last two seasons. The severity of powdery mildew and septoria leaf spot (mainly Septoria tritici) varied between seasons from slight to moderate with powdery mildew dominating in the first season and septoria leaf spot in the last season. The severity of both powdery mildew and septoria leaf spot assessed as the Area Under the Disease Progress Curve (AUDPC) was increased by application of N in all years, and more so by early applied N. Grain yields increased with increasing N rate and fungicide dose. However, the observed grain yields did not reveal any N×fungicide interactions. Regression models were therefore fitted, relating grain yield to rate and timing of N fertilizer and to AUDPC of powdery mildew and septoria leaf spot, and relating AUDPC to rate and timing of N fertilizer and to fungicide dose. They demonstrated that septoria leaf spot had a considerably higher impact on grain yield than mildew. The optimal fungicide dose and N rate were defined as those giving the highest economic return. The regression models were used to estimate the effect of N rate and timing on optimal fungicide dose, and the effect of fungicide application on optimal N rate. The optimal fungicide dose increased almost linearly with N rate above a minimum N rate, but with a large dependency on price relations. Early applied N caused a higher demand for disease control. The fungicide applications in the model were mainly driven by the need to control septoria leaf spot, whereas powdery mildew gave a poor net return for control. The estimated optimal N fertilizer rate for untreated diseased crops was 60 kg N/ha lower than for crops without disease. The use of fungicides with an efficacy twice that of the EBI-fungicides used in this experiment would increase the optimal N rate by c. 20 kg N/ha.
14
Yellareddygari, S. K. R., Julie S. Pasche, Raymond J. Taylor, and Neil C. Gudmestad. "Individual Participant Data Meta-Analysis of Foliar Fungicides Applied for Potato Early Blight Management." Plant Disease 100, no. 1 (January 2016): 200–206. http://dx.doi.org/10.1094/pdis-05-15-0530-re.
Full textAbstract:
Foliar fungicides continue to be the primary means of early blight management on potato in the United States. Both premium-priced, single-site mode-of-action “specialty” fungicides and standard protectant multisite fungicides are applied, either alone or incorporated into fungicide rotation programs to combat early blight. Individual participant data meta-analysis was conducted to compare overall fungicide efficacy against early blight on potato, quantify tuber yields, and identify the most efficacious timing for fungicide applications. In this study, the specialty fungicide-based applications were compared against the standard fungicides chlorothalonil and mancozeb applied alone. Type 3 fixed effects indicated that there was a significant difference (P < 0.0001) in overall efficacy and yield among the treatments applied to manage early blight in potato. There was a significant difference (P < 0.0001) among treatments in early blight development during the growing season. Applications incorporating specialty fungicides, when compared with standard fungicides, significantly affected disease severity from vegetative growth initiation (P = 0.0139) to tuber maturation (P = 0.0009). Results demonstrate that the higher cost, specialty-fungicide-based applications were most effective for early blight management in North Dakota and Minnesota.
15
Uddin, W., M. D. Soika, A. S. McNitt, and M. Fidanza. "Effects of Timing of Ethofumesate Application on Severity of Gray Leaf Spot of Perennial Ryegrass Turf." Plant Disease 88, no. 10 (October 2004): 1146–52. http://dx.doi.org/10.1094/pdis.2004.88.10.1146.
Full textAbstract:
Ethofumesate is a widely used herbicide for control of annual bluegrass (Poa annua) in perennial ryegrass (Lolium perenne) fairways on golf courses in the United States. Effect of timing of ethofumesate application on development of gray leaf spot was evaluated on perennial ryegrass turf treated with six classes of fungicide. Two applications of ethofumesate (2.28 kg a.i./ha) were made to perennial ryegrass turf maintained at a 2-cm height, at 4-week intervals, each fall (October and November 1999 and 2000) or spring (April and May 2000 and 2001). In addition, turf was treated with the fungicides, azoxystrobin, chlorothalonil, flutolanil, iprodione, propiconazole, or thiophanate-methyl at the label rates at 14-day intervals. There were significant effects (P ≤ 0.05) of ethofumesate application timing and fungicide regime on gray leaf spot development. There also were significant interactions between the ethofumesate application timing and fungicide. Severity of gray leaf spot was significantly greater in turf plots treated with ethofumesate in spring compared to turf treated in fall or nontreated control plots treated with fungicides, flutolanil, iprodione, and propiconazole that were relatively less effective in control of gray leaf spot. There was no significant difference in disease severity in turf treated with ethofumesate in fall or to turf not treated with herbicide regardless of the fungicide used. Results of this study indicate that spring application of ethofumesate contributes to development of gray leaf spot epidemics, and the application timing interacts with the classes of fungicides. This study suggests that ethofumesate should be applied only in fall for control of P. annua, particularly in golf courses with a chronic gray leaf spot problem, as part of an integrated management of gray leaf spot in perennial ryegrass fairways.
16
Mueller, D. S., S. N. Jeffers, and J. W. Buck. "Effect of Timing of Fungicide Applications on Development of Rusts on Daylily, Geranium, and Sunflower." Plant Disease 88, no. 6 (June 2004): 657–61. http://dx.doi.org/10.1094/pdis.2004.88.6.657.
Full textAbstract:
Integrated disease management should provide the most effective means of controlling rusts on ornamental crops over time, and fungicides are an important component of an integrated rust management program. Proper timing of fungicide applications is critical for effective disease management; however, information about application timing is lacking for rusts on ornamental crops. The objective of this study was to determine how fungicides affected rust development on daylily, geranium, and sunflower plants when applied several days before or after inoculation. Five fungicides registered for use against rusts on ornamental crops were evaluated: the strobilurin azoxystrobin; three sterol biosynthesis inhibiting fungicides—myclobutanil, propiconazole, and triadimefon; and the broad spectrum protectant chlorothalonil. All five fungicides significantly reduced lesion development by rust pathogens on daylily, geranium, and sunflower plants when these compounds were applied preventatively up to 15 days before inoculation and infection with a few exceptions (e.g., propiconazole on geranium and triadimefon on sunflower). Curative activity, which resulted from fungicide application after inoculation, was observed for the three rusts with some products (azoxystrobin on all three plants and myclobutanil, propiconazole, and triadimefon on geranium) when applied up to 7 days postinoculation. In general, fungicide efficacy with several of the products decreased as the time from application to inoculation (preventative activity) or inoculation to application (curative activity) increased.
17
Bounds, R. S., R. H. Podolsky, and M. K. Hausbeck. "Integrating Disease Thresholds with TOM-CAST for Carrot Foliar Blight Management." Plant Disease 91, no. 7 (July 2007): 798–804. http://dx.doi.org/10.1094/pdis-91-7-0798.
Full textAbstract:
Cercospora carotae and Alternaria dauci cause foliar blight on carrot (Daucus carota subsp. sativus) and are managed with fungicides to prevent yield loss. Sprays are initiated prior to disease symptoms and reapplied frequently, but some of these applications may not be necessary when the threat of disease is low. Delaying the initial fungicide spray until disease symptoms are observed and applying subsequent sprays according to the TOM-CAST disease forecaster may reduce fungicide inputs. The objective of this 2-year field study was to compare preventive, calendar-based application schedules with an integrated management approach that incorporates disease scouting to initiate fungicide application and the TOM-CAST system for timing subsequent fungicide sprays to manage foliar blight on processing, fresh market, and cut-and-peel carrot cultivars in Michigan. Applications of the fungicides chlorothalonil alternated with azoxystrobin were made prior to disease symptoms (0% blight) or when the foliage became blighted at a trace, 5%, or 10% severity level. Fungicides were reapplied every 7 or 10 days or according to TOM-CAST using disease severity value (DSV) thresholds of 15, 20, or 25. Initiating fungicide treatment at a trace level of disease and timing subsequent sprays according to the TOM-CAST 15-DSV forecaster was comparable to the preventive, calendar-based fungicide regime. One to five fewer applications were needed, while fungicide costs were reduced by $21 to $141 per hectare, when spraying at the trace disease threshold and reapplying according to the TOM-CAST 15-DSV program compared with the 7- or 10-day intervals initiated at 0% blight. Fungicide programs initiated at 5 or 10% leaf blight often provided less control than programs initiated at 0% and trace disease. This study highlights the importance of initiating a fungicide program prior to advanced foliar blight and validates the TOM-CAST 15-DSV forecaster for managing Cercospora leaf spot and Alternaria leaf blight in three carrot production systems.
18
Faske, Travis R., and Michael Emerson. "Multiyear Evaluation of Fungicide Efficacy and Application Timing for Control of Southern Rust in Hybrid Corn in Arkansas." Plant Disease 105, no. 4 (April 2021): 1108–14. http://dx.doi.org/10.1094/pdis-06-20-1247-re.
Full textAbstract:
The efficacy and timing of eight foliar fungicides to manage southern rust of corn (caused by Puccinia polysora Underwood) was investigated over 4 years in three field experiments. Each experiment consisted of one-, two-, or three-fungicide application timings at tassel, milk, or dent growth stages with quinone outside inhibitor (QoI), demethylation inhibitor (DMI), or QoI + DMI fungicides. Each year trace amounts of southern rust were observed in the field at tassel, except in 2018, when rust was not observed until physiological maturity. Southern rust severity on ear leaf and two leaves above the ear leaf was approximately 50, 35, 75, and 0% at dent in 2015, 2016, 2017, and 2018, respectively. Applications that contained a QoI or QoI + DMI fungicide provided greater southern rust control than DMI fungicides, with little variation within fungicide classes. Applications of QoI or QoI + DMI fungicides applied at tassel provided greater disease control (52.5%) than those applied at milk (5.8%) or dent (1.4%), and greater yield protection (40.4%) than those applied at milk (23.7%) or dent (2.6%) when final rust development was severe (>40%). When rust development increased later in the season, after milk growth stage, a trend of better disease control was observed with fungicides applied at milk (57.8%) compared with tassel (35.2%), but grain yield protection was similar, with an average yield protection of 7.4%. There was no yield benefit with fungicides applied in the absence of disease or at the dent growth stage. Southern rust was most effectively managed with QoI or QoI + DMI fungicides applied at tassel when southern rust was present and environmental conditions favored rust development.
19
Leiminger, J. H., and H. Hausladen. "Early Blight Control in Potato Using Disease-Orientated Threshold Values." Plant Disease 96, no. 1 (January 2012): 124–30. http://dx.doi.org/10.1094/pdis-05-11-0431.
Full textAbstract:
Epidemics of early blight caused by Alternaria spp. can cause significant economic damage to potato production if not adequately controlled. In order to improve control of Alternaria spp. in potato, studies were conducted to identify the optimal fungicide strategy and, if possible, to reduce the number of fungicide applications per growing season. Therefore, a disease-threshold-based framework was tested to define the optimal timing of fungicide application. The initiation and subsequent applications of fungicides were based on increases in disease incidence or severity. Adequate disease control was achieved by a three-time application with azoxystrobin, given that the applications were carried out at pivotal times in the epidemic. Targeted applications of fungicides reduced the number of sprayings required to protect starch yield. Results indicate that early blight can be effectively managed by using fungicide application thresholds based on disease progress.
20
Ward, J. M. J., M. D. Laing, and F. H. J. Rijkenberg. "Frequency and Timing of Fungicide Applications for the Control of Gray Leaf Spot in Maize." Plant Disease 81, no. 1 (January 1997): 41–48. http://dx.doi.org/10.1094/pdis.1997.81.1.41.
Full textAbstract:
Timing and frequency of fungicide treatments for management and control of gray leaf spot of maize, caused by Cercospora zeae-maydis, were quantified with the logistic model and area under disease progress curve (AUDPC). Control was most effective when spraying commenced as disease severity levels reached 2 to 3% of the leaf area blighted and when lesions were restricted to the basal five leaves of the maize plant. Highest grain yields were achieved with treatments providing disease control until the crop was physiologically mature. To provide this length of control, the frequency and number of fungicide applications varied with the stage of host development when disease was first apparent; with early infections, more fungicide treatments were necessary to provide protection until physiological maturity. Yield responses to fungicides appeared to be a function of the growth stage of the host when sprays were initiated, the amount of disease at spray date, the length of fungicide control, and effective control through to physiological maturity.
21
Claassen, Briana J., Sierra N. Wolfenbarger, and David H. Gent. "Fungicide Physical Mode of Action: Impacts on Suppression of Hop Powdery Mildew." Plant Disease 106, no. 4 (April 1, 2022): 1244–52. http://dx.doi.org/10.1094/pdis-10-21-2131-re.
Full textAbstract:
Understanding of the physical mode of action of fungicides allows more efficient and effective application and can increase disease control. Greenhouse and field studies were conducted to explore the preinfection and postinfection duration and translocative properties of fungicides commonly used to control hop powdery mildew, caused by Podosphaera macularis. In greenhouse studies, applications made 24 h before inoculation were almost 100% effective at suppressing powdery mildew, regardless of the fungicide evaluated. However, percentage control of powdery mildew based on the number of pathogen colonies per leaf varied significantly between fungicides with increasing time from inoculation to application, ranging from 50 to 100% disease control depending on the fungicide. Fluopyram or fluopyram + trifloxystrobin was particularly efficacious, suppressing nearly all powdery mildew development independent of application timing. In translocation studies, fluopyram and flutriafol were the most effective treatments in each of two separate experiments, resulting in zones of inhibition of 1,036 and 246.3 mm2, respectively, on adaxial leaf surfaces when a single droplet of each fungicide was applied to the abaxial surface of leaves. In field experiments, all fungicide treatments provided nearly complete control of powdery mildew infection when applied before inoculation. Levels of disease control decreased with time depending on treatment, showing trends similar to those observed in greenhouse studies. In the 2017 field experiments, high levels of disease control (>75%) were observed at postinoculation time points for all treatments tested, whereas the same fungicides were more sensitive to application timing in a different year. Findings from this research indicate that differences in efficacy between fungicides are small when applications are made preventively, but postinfection activity and translaminar movement of certain fungicides may render some more effective depending on application coverage and preexisting infection.
22
Mesterházy, Á., T. Bartók, and C. Lamper. "Influence of Wheat Cultivar, Species of Fusarium, and Isolate Aggressiveness on the Efficacy of Fungicides for Control of Fusarium Head Blight." Plant Disease 87, no. 9 (September 2003): 1107–15. http://dx.doi.org/10.1094/pdis.2003.87.9.1107.
Full textAbstract:
Attempts to control Fusarium head blight (FHB) with fungicides have been highly variable. Variability is caused by cultivar resistance, fungicide efficacy, fungicide coverage, timing, and pathogen aggressiveness. In this research, fungicides were tested on winter wheat cultivars with different levels of resistance to FHB using different isolates of Fusarium graminearum and F. culmorum to evaluate the role of host resistance and isolate aggressiveness on severity of FHB. Fungicides were applied to groups of wheat heads to provide full coverage. Incidence and severity of FHB was measured by the severity of head symptoms, percentage of Fusarium-damaged kernels (FDK), yield loss, and deoxynivalenol (DON) contamination. Development of FHB was affected by fungicides, cultivars, fungal isolates, and most of the two-way interactions of these variables. Among the fungicides tested, those containing tebuconazole tended to be more effective in reducing FHB. Reduction of disease in susceptible cultivars may not be adequate to produce marketable yields under conditions of high disease pressure. In most cases, if a fungicide reduced FHB visual symptoms, similar decreases were detected in yield loss, DON concentration, and FDK reaction. In 1998, an increase in DON contamination compared with the Fusarium check was observed with azoxystrobin and carbendazim on the more susceptible cultivar. This increase in DON with some fungicide requires additional research. Research to develop more resistant cultivars, better spraying technology, and more effective fungicides is also needed.
23
Groth, D. E., and J. A. Bond. "Initiation of Rice Sheath Blight Epidemics and Effect of Application Timing of Azoxystrobin on Disease Incidence, Severity, Yield, and Milling Quality." Plant Disease 90, no. 8 (August 2006): 1073–76. http://dx.doi.org/10.1094/pd-90-1073.
Full textAbstract:
The lack of sheath blight-resistant cultivars requires rice (Oryza sativa) farmers to use fungicides to control the disease and avoid significant reductions in grain and milling yield. Sheath blight (Rhizoctonia solani) epidemics can begin over a period of weeks during the growing season, and initiation date can have significant effects on crop damage and fungicide application timing. Studies were conducted to determine how different epidemic initiation and azoxystrobin application timings affect disease development, rice yield, and milling quality. Sheath blight epidemics in field plots were initiated by inoculation at the green ring (GR), panicle differentiation (PD), early boot (EB), and late boot (LB) growth stages in 2002 to 2004. Azoxystrobin was applied to the foliage at 0.17 kg a.i. ha-1 at 7 days after PD (PD+7), midboot (B), and 50% heading (H). Inoculation significantly increased sheath blight severity and incidence and reduced yield and milling quality. There were no significant effects of inoculation timing at the GR, PD, EB, and LB growth stages. Fungicide applications made between PD+7 and H reduced sheath blight severity and incidence, resulting in higher yield and head rice milling yield compared with inoculated but nonsprayed plots.
24
Mueller, T. A., M. R. Miles, W. Morel, J. J. Marois, D. L. Wright, R. C. Kemerait, C. Levy, and G. L. Hartman. "Effect of Fungicide and Timing of Application on Soybean Rust Severity and Yield." Plant Disease 93, no. 3 (March 2009): 243–48. http://dx.doi.org/10.1094/pdis-93-3-0243.
Full textAbstract:
Soybean rust, caused by Phakopsora pachyrhizi, is a devastating foliar disease of soybean that may cause significant yield losses if not managed by well-timed fungicide applications. To determine the effect of fungicide timing on soybean rust severity and soybean yield, field trials were completed in Paraguay (four locations), the United States (two locations), and Zimbabwe (one location) from 2005 to 2006. Treatments at each location included applications of tebuconazole, pyraclostrobin, or a combination of azoxystrobin + propiconazole, and in some locations pyraclostrobin + tebuconazole at the following soybean growth stages (GS): (i) GS R1 (beginning flowering), (ii) GS R3 (beginning pod), (iii) GS R5 (beginning seed), (iv) GS R1 + R3, (v) GS R3 + R5, and (vi) GS R1 + R3 + R5. Soybean yields from plots treated with fungicides were 16 to 114% greater than yields from no fungicide control plots in four locations in Paraguay, 12 to 55% greater in two locations in the United States, and 31% greater in Zimbabwe. In all locations, rust severity measured over time as area under the disease progress curve (AUDPC) was negatively correlated (r = –0.3, P < 0.0001) to yield. The effectiveness of any given treatment (timing of application and product applied) was often dependent on when rust was first detected and the intensity of its development. For example, when soybean rust was first observed before GS R3 (two locations in Paraguay), the plants in plots treated with a fungicide at GS R1 had the lowest AUPDC values and highest yields. When soybean rust was first observed after GS R3, plants treated with a fungicide at GS R3 and/or GS R5 had the lowest AUDPC values and highest yields with a few exceptions.
25
Friskop, Andrew, Shashi Yellareddygari, Neil C. Gudmestad, Kate Binzen Fuller, and Mary Burrows. "Low Benefits from Fungicide Use on Hard Red Wheat in Low-Disease Environments." Plant Health Progress 19, no. 4 (January 1, 2018): 288–94. http://dx.doi.org/10.1094/php-06-18-0028-rs.
Full textAbstract:
The use of fungicides on hard red wheat in the northern Great Plains increased in part owing to inexpensive fungicide options and several years of foliar disease epidemics. In some instances, fungicides are used in the absence of disease, prompting questions on the perceived value of these applications. This study analyzed yield data from 46 fungicide trials conducted in low-disease environments from 2007 to 2014 on hard red spring wheat and hard red winter wheat. Data were sorted and organized to determine yield response attributed to fungicide application timing (Feekes 2–3 or Feekes 9) and fungicide mode of action. Fungicide modes of action included quinone outside inhibitors (QoIs), demethylation inhibitors (DMIs), succinate dehydrogenase inhibitors (SDHIs), and blends (mixtures of QoI, DMI, or SDHI). A meta-analysis indicated a significant yield response of 101.6 kg/ha for a Feekes 9 application and 69.3 kg/ha for applications that used a QoI. Economic analyses indicated that when a midpoint value for both wheat price and application cost were used, less than one-third of the trials had a profitable net return when a Feekes 9 application was used. The infrequent positive yield responses associated with foliar fungicides in low-disease environments should prompt growers to evaluate disease risk prior to making an application for foliar diseases.
26
Conry, M. J., and B. Dunne. "Effects of nitrogen timing and frequency of fungicide applications on grain yields of winter barley in Ireland." Journal of Agricultural Science 120, no. 2 (April 1993): 181–86. http://dx.doi.org/10.1017/s0021859600074219.
Full textAbstract:
SUMMARYThe effects of varying the timing of nitrogen application and the frequency of fungicide sprays on the incidence of foliar disease and on the grain yield of winter barley (cv. Panda) were investigated at two sites in Ireland over three years, 1986–88. Nitrogen application timing had little effect on the amount of foliar necrosis due to disease but delaying application of all the nitrogen until April significantly reduced grain yields in two of the three years when compared with standard split dressings in March and April. The reductions in yield reflected small differences in 1000-grain weight.The number of fungicide sprays applied had significant effects on the amount of foliar necrosis and on grain yields. One-spray and two-spray programmes increased average yield by 16 and 32%, respectively. The yield increases were attributable to more ears/m2 and larger grains (greater 1000-grain weight). Fungicides also delayed the onset and significantly reduced the amount of brackling. Delaying nitrogen application in the spring did not decrease the number of fungicide sprays required to achieve maximum yield.
27
Pathan, Amin K., William Cuddy, Mark O. Kimberly, Kwasi Adusei-Fosu, Carol A. Rolando, and Robert F. Park. "Efficacy of Fungicides Applied for Protectant and Curative Activity Against Myrtle Rust." Plant Disease 104, no. 8 (August 2020): 2123–29. http://dx.doi.org/10.1094/pdis-10-19-2106-re.
Full textAbstract:
Myrtle rust, caused by the pathogen Austropuccinia psidii, affects species of the Myrtaceae, many of which are endemic to Australia and New Zealand. Originating from South America, A. psidii is now present in both countries, necessitating effective chemical control for disease management. Using an artificial inoculation protocol, the efficacy of eight fungicides (tebuconazole/trifloxystrobin, cyproconazole/azoxystrobin, fosetyl aluminum, triforine, triadimenol, oxycarboxin, copper, and tebuconazole) applied as curative or protectant treatments was tested on two native New Zealand species (Lophomyrtus × ralphii and Metrosideros excelsa). The impacts of rate (×2), frequency (single or double), and timing (pre- or postinfection) of fungicide application were investigated. Overall, the most effective fungicides tested across both species were those that included a demethylation inhibitor and strobilurin mix, notably tebuconazole/trifloxystrobin (Scorpio) and cyproconazole/azoxystrobin (Amistar Xtra). These fungicides significantly reduced infection of host plants relative to the water control. Timing of application significantly affected bioefficacy, with applications made 7 days before inoculation or 7 days after inoculation being generally the most effective. The rate of fungicide application was not significant for both host species, with few interaction terms showing overall significance. Key findings from this study will set the foundation for further fungicide bioefficacy research conducted to evaluate formulations and adjuvant mixtures, determine suitable application methods for enhanced retention and coverage, and derive optimum application time for effective protection of native and exotic Myrtaceae species in New Zealand.
28
Cowger, Christina, Consuelo Arellano, David Marshall, and Joshua Fitzgerald. "Managing Fusarium Head Blight in Winter Barley With Cultivar Resistance and Fungicide." Plant Disease 103, no. 8 (August 2019): 1858–64. http://dx.doi.org/10.1094/pdis-09-18-1582-re.
Full textAbstract:
Although there has been research on managing Fusarium head blight (FHB) in spring barley, little has been published on cultivar resistance and optimal fungicide timing for FHB management in winter barley. A 3-year (2015 to 2017) field experiment was conducted to measure FHB resistance of winter barley varieties, gauge the potential benefit from a fungicide, and help determine the optimal timing for fungicide application. The split-plot experiment took place in a misted, inoculated nursery in Raleigh, North Carolina using main plots of four winter barley cultivars (Atlantic, Endeavor, Nomini, and Thoroughbred). Three fungicide treatments were applied to subplots: prothioconazole + tebuconazole at full spike emergence, the same fungicide 6 days later, or no fungicide. The late applications significantly reduced FHB index in each of 3 years and significantly reduced deoxynivalenol (DON) in harvested grain in 2 of the 3 years. Applications at full spike emergence also yielded significant benefit in 1 of the 3 years for each parameter. Neither disease symptoms nor DON gave reason to prefer one of the fungicide timings over the other. Across the 3 years, DON ranked the cultivars Endeavor < Nomini = Thoroughbred < Atlantic. Combining the moderate resistance of Endeavor with a fungicide application and averaging the two timings resulted in a 75% DON reduction compared with unsprayed Atlantic. Taken together, our results indicate that barley growers concerned about minimizing DON should both plant moderately resistant varieties and apply fungicide if there is scab risk. During the same period, 16 commercial winter barley cultivars were tested in from three to seven Virginia and North Carolina environments each, and the DON results were compared after standardization across environments. The winter two-row malting barley cultivars Endeavor and Calypso displayed superior and robust DON resistance across environments.
29
Pfender, W. F., and J. Eynard. "Field Assessment of a Model for Fungicide Effects on Intraplant Spread of Stem Rust in Perennial Ryegrass Seed Crops." Phytopathology® 99, no. 6 (June 2009): 696–703. http://dx.doi.org/10.1094/phyto-99-6-0696.
Full textAbstract:
Intraplant spread of stem rust (Puccinia graminis subsp. graminicola) in perennial ryegrass during tiller extension is a major determinant of epidemic severity and is dominated by stem extension dynamics. Simple equations for extension of inflorescence and internodes are presented and parameterized. These equations are combined with previously published equations for pathogen latent period and for postinfection efficacy of fungicides to produce a model for effects of fungicide type and timing on intraplant spread. The model is driven by thermal units, calculated from air temperature measurements. Three field experiments, conducted independently from the field experiments that provided data for plant growth model parameterization, were conducted to assess performance of the disease spread model. Either propiconazole or azoxystrobin, the two most commonly used fungicides for stem rust control, was applied to tillers that had stem rust pustules on the flag sheath and in which the inflorescence was partially extended. Intraplant spread of disease to the extending inflorescence (stem and flowerhead) was observed at several dates following treatment and compared with modeled severities. The model estimated accurately the severities of inflorescence infection for most treatments and observation times, with a correlation coefficient of 0.93 for modeled versus observed disease severities across the three experiments. The model correctly estimated the rank order of final severities among the treatments (fungicide type and timing). The model can be extended to intraplant spread of stem rust at all internodes and incorporated into decision support tools for fungicide type and timing in management of this disease.
30
Strickland, David A., Sara M. Villani, and Kerik D. Cox. "Optimizing Use of DMI Fungicides for Management of Apple Powdery Mildew Caused by Podosphaera leucotricha in New York State." Plant Disease 106, no. 4 (April 1, 2022): 1226–37. http://dx.doi.org/10.1094/pdis-09-21-2025-re.
Full textAbstract:
Powdery mildew, caused by the ascomycete Podosphaera leucotricha, is an endemic disease found wherever apples are grown that reduces both tree vigor and fresh market yield. In the absence of durable host resistance, chemical management is the primary means of disease control. Demethylation inhibitor (DMI) fungicides are widely used to manage apple powdery mildew, but members within this fungicide class have been observed to differ in efficacy with respect to disease control. Moreover, debate exists as to the optimal timing of DMI fungicide applications for management of apple powdery mildew. In this regard, the goal of this study was to determine the best-use practices for DMI fungicides to manage apple powdery mildew in New York State. Multiyear trials were conducted to evaluate the potential differential efficacy performance of four common DMI fungicides, and additional trials were conducted to assess optimal application timing. In all years, we observed that treatments of flutriafol and myclobutanil consistently had the lowest incidences of powdery mildew compared with difenoconazole and fenbuconazole. In the 2018 and 2021 trials, the newly registered mefentrifluconazole was more comparable to the difenoconazole program with respect to powdery mildew disease incidence. We hypothesize that differences in DMI efficacy may result from each fungicide’s water solubility and lipophilicity characteristics and thus their ability to move systemically in the host or more easily penetrate the surface of germinating conidia. Applications timed between petal fall and first cover resulted in the lowest incidence of powdery mildew on terminal leaves of apple shoots compared with applications timed before petal fall. These observations are contrary to previous studies conducted in regions with differing climates. We also found that the incidence of secondary powdery mildew observed 2 weeks after petal fall was influenced by applications of DMI fungicides during the previous season. For example, management programs consisting of applications of flutriafol or myclobutanil in the previous season tended to have lower incidence of apple powdery in the next spring, presumably because of reductions in overwintering inoculum. Despite reports of DMI resistance in other apple pathosystems, the DMI fungicide class is still relevant for the successful management of apple powdery mildew in New York State.
31
Gao, Y. Y., X. X. Li, L. F. He, B. X. Li, W. Mu, and F. Liu. "Effect of Application Rate and Timing on Residual Efficacy of Pyraclostrobin in the Control of Pepper Anthracnose." Plant Disease 104, no. 3 (March 2020): 958–66. http://dx.doi.org/10.1094/pdis-03-19-0435-re.
Full textAbstract:
Anthracnose is a devastating disease that seriously affects pepper production worldwide. Anthracnose management is currently a major problem because of the widespread and long period of infection of this disease. Therefore, determination of the optimal fungicide application timing is important for controlling anthracnose in a timely manner . In vitro sensitivity tests showed no significant difference in the pyraclostrobin sensitivity of Colletotrichum scovillei collected from 2016 and 2017, with mean half maximal effective concentration values of 0.349 to 0.542 and 0.0475 to 0.0639 mg/liter for the inhibition of mycelial growth and spore germination, respectively. Fungicide application initiated at the full-bloom stage could significantly delay anthracnose disease onset, decrease anthracnose incidence and development (23.67 to 89.80%), and increase pepper yield by 10.7 to 29.2%. In addition, the application dosage was decreased by >50%. BF-500-3, the main metabolite of pyraclostrobin, was detected in pepper fruit and exhibited high inhibitory activity against C. scovillei. The final residues of all fungicides at different application timing were below maximum residue limits. Moreover, structural equation modeling indicated that application timing plays the most important role in anthracnose disease inhibition. The tank mixtures of pyraclostrobin with tebuconazole and fludioxonil showed more satisfactory efficacy (69.87 to 78.36%) against anthracnose than did pyraclostrobin alone under field conditions. This study is the first to determine the best fungicide application timing for anthracnose management. These results establish the basis for sustainable development of the pepper industry.
32
Groth, D. E. "Azoxystrobin Rate and Timing Effects on Rice Sheath Blight Incidence and Severity and Rice Grain and Milling Yields." Plant Disease 89, no. 11 (November 2005): 1171–74. http://dx.doi.org/10.1094/pd-89-1171.
Full textAbstract:
Lack of sheath blight resistant varieties requires rice (Oryza sativa) farmers to use fungicides to avoid significant reductions in grain yield and milling yield. Studies were conducted to determine the best rate and rice growth stage for a single application of azoxystrobin, a fungicide recently labeled for this use, to effectively control sheath blight. Azoxystrobin was applied foliarly to inoculated field plots in 2000 to 2002 using rates of 0.22, 0.17, and 0.11 kg a.i. ha -1 at 7 days after panicle differentiation (PD+7), boot (B), and heading (H) growth stages and at 0.17 kg a.i. ha-1 at 5, 10, and 15 days after heading. Sheath blight severity (measured on a 0 to 9 scale) and incidence (percent tillers infected) were assessed 1 to 2 weeks before harvest. A fungicide application made between PD+7 and H significantly reduced sheath blight severity, which resulted in significantly higher yield and head rice milling yield compared with inoculated unsprayed plots. There were no significant effects of fungicide rate at the PD+7, B, and H growth stages. Fungicide-treated plots had yield and milling yield similar to the very lightly diseased, uninoculated check plots included for comparison. With fungicide application made postheading, rice had higher disease severity, resulting in lower yields and milling yield compared with rice receiving earlier applications.
33
Marroni, M. V., S. L. H. Viljanen-Rollinson, R. C. Butler, and Y. Deng. "Fungicide timing for the control of septoria tritici blotch of wheat." New Zealand Plant Protection 59 (August 1, 2006): 160–65. http://dx.doi.org/10.30843/nzpp.2006.59.4550.
Full textAbstract:
A field trial during the 200506 growing season used different fungicides and timing of fungicide applications to manipulate the development of Septoria tritici blotch on artificiallyinoculated wheat (cv Consort) Disease severity was assessed once or twice a week and the area under the disease progress curve (AUDPC) calculated The fungicide azoxystrobin applied at the prestem extension stage of crop growth had the lowest AUDPC and provided the best level of protection against the disease on the top three leaves Good control of the disease was also obtained from prestem extension and stemextension (growth stage GS32) applications of a mixture of azoxystrobin and epoxiconazole Epoxiconazole applied at the prestem extension stage and azoxystrobin and epoxiconazole mixture applied at growth stages 37 and 39 did not provide adequate control of the disease This work is part of a project aiming to provide information for development of disease models and forecast systems to assist growers with disease control decisions
34
Bestor, Nathan R. C., Alison E. Robertson, and Daren S. Mueller. "Effect of Foliar Fungicides on Late-season Anthracnose Stem Blight on Soybean." Plant Health Progress 15, no. 3 (January 2014): 118–21. http://dx.doi.org/10.1094/php-rs-14-0013.
Full textAbstract:
Anthracnose stem blight, caused by Colletotrichum truncatum, is responsible for soybean (Glycine max) yield losses in subtropical and tropical growing regions. There are inadequate data regarding the effect of anthracnose stem blight on yield in Iowa, and it is unknown if fungicide application can manage this disease. Field studies were conducted from 2008 to 2010 to determine the effect of fungicide application timing on late-season development of this disease. We also investigated the effect of anthracnose stem blight on yield and specific yield components. Fungicides reduced late-season symptom development when compared to the untreated control; however, there were no differences in yield and yield components. While foliar fungicides can reduce late-season disease development, anthracnose stem blight typically should not affect crop management decisions involving use of foliar fungicides on soybean in Iowa. Accepted 7 July 2014. Publication 14 August 2014.
35
Bounds, R. S., M. K. Hausbeck, and R. H. Podolsky. "Comparing Disease Forecasters for Timing Fungicide Sprays to Control Foliar Blight on Carrot." Plant Disease 90, no. 3 (March 2006): 264–68. http://dx.doi.org/10.1094/pd-90-0264.
Full textAbstract:
Alternaria dauci and Cercospora carotae cause foliar blight on carrot and can reduce yield in severely blighted fields. Historically, fungicides are applied every 7 to 14 days even though applications may be made when environmental conditions do not favor blight development. The purpose of this study was to compare a calendar-based application schedule with three disease forecasting systems for timing fungicide sprays to limit foliar blight, and included (i) an A. dauci disease forecaster, (ii) TOM-CAST, using a threshold of 15 disease severity values, and (iii) a disease forecaster developed to control C. apii on celery. Chlorothalonil was applied weekly or according to the forecasting systems to blight-susceptible ‘Cellobunch’ carrot plants in 2001 and 2002. Overall petiole health was poor ≥8.3; 10 = 100% petiole necrosis) when fungicides were not used. Although all disease forecasters maintained petiole health (≤5.3; 1 = healthy and vigorous), the TOM-CAST program had the best petiole health rating each year (≤2.8). TOM-CAST prompted 38 to 54% fewer applications than the weekly application schedule, resulting in a fungicide savings of $105 and $147/ha in 2001 and 2002, respectively, while providing similar blight control. The number of sprays also was reduced when fungicides were applied according to the A. dauci and C. apii forecasters, but acceptable blight control was not always achieved.
36
Singh, Lovepreet, Taylor Schulden, Jason P. Wight, Joseph Crank, Louis Thorne, John E. Erwin, Yanhong Dong, and Nidhi Rawat. "Evaluation of Application Timing of Miravis Ace for Control of Fusarium Head Blight in Wheat." Plant Health Progress 22, no. 2 (January 1, 2021): 94–100. http://dx.doi.org/10.1094/php-01-21-0007-rs.
Full textAbstract:
Fusarium head blight (FHB) is a serious disease of wheat and barley that not only lowers yield but also contaminates the grain with associated mycotoxins such as deoxynivalenol (DON). Chemical control options for FHB and DON include application of triazole fungicides at the anthesis or flowering stage. This presents practical challenges for growers in managing FHB, as the appropriate timing window typically lasts only 3 to 4 days. If this small window is missed, due to weather conditions or technical problems, fungicide application is less effective in controlling FHB and DON. The present work was conducted over 2 years (2019 and 2020) to test the efficacy of a new fungicide (pydiflumetofen + propiconazole) from Syngenta labeled as Miravis Ace in controlling FHB and DON content at 50% head emergence (Feekes 10.3), anthesis (Feekes 10.5.1), and end of flowering (Feekes 10.5.3) stages. Prosaro 421 SC, a standard FHB control triazole fungicide, was used at all three stages for comparison with the test fungicide. Miravis Ace application at 50% head emergence provided significant control over the nontreated check for FHB incidence (2020), FHB severity (2019), and DON content (2019) with control efficacies as high as 51, 69, and 52%, respectively. However, mean control percentages relative to the check were highest with Miravis Ace at anthesis in both 2019 and 2020 for all the FHB parameters. In conclusion, 50% head emergence provides statistically significant control on FHB and DON, but anthesis was the most effective application stage for Miravis Ace.
37
Yoshida, Megumi, Takashi Nakajima, Kenta Tomimura, Fumihiko Suzuki, Michiyoshi Arai, and Atsushi Miyasaka. "Effect of the Timing of Fungicide Application on Fusarium Head Blight and Mycotoxin Contamination in Wheat." Plant Disease 96, no. 6 (June 2012): 845–51. http://dx.doi.org/10.1094/pdis-10-11-0819.
Full textAbstract:
Fungicide application to control Fusarium head blight (FHB) and accompanying mycotoxin contamination in wheat is generally performed at anthesis because wheat is most susceptible to FHB around this stage. In this study, we evaluated the effect of the timing of fungicide application on FHB and mycotoxin (deoxynivalenol and nivalenol) accumulation in wheat based on our previous finding that the late period of grain development (beyond 20 days after anthesis [DAA]) is important to determine the final toxin contamination level in wheat. Thiophanate-methyl fungicide was tested under artificial inoculation conditions in which moisture and inoculum spores were provided throughout the testing period. Eight treatments differing in application timing (anthesis, 10, 20, and 30 DAA) and in the number of applications (0 to 2) were tested for 2 years. The results indicated that fungicide application timing differentially affects FHB (disease) and mycotoxin concentration. Fungicide application at 20 DAA reduced mycotoxin concentration in matured grain without reducing FHB severity, whereas application at anthesis was crucial for reducing FHB. These results and our previous findings suggest that around 20 DAA (late milk stage) is a potentially critical timing for mycotoxin control in wheat.
38
Acharya, Bhupendra, Thomas N. O’Quinn, Wesley Everman, and Hillary L. Mehl. "Effectiveness of Fungicides and Their Application Timing for the Management of Sorghum Foliar Anthracnose in the Mid-Atlantic United States." Plant Disease 103, no. 11 (November 2019): 2804–11. http://dx.doi.org/10.1094/pdis-10-18-1867-re.
Full textAbstract:
Sorghum anthracnose (Colletotrichum sublineola) reduces grain yield up to 50% but suggested management tactics have not yet been developed for the mid-Atlantic United States, where warm, wet conditions favor disease. Under factorial arrangement, five fungicides plus a nontreated control and four application timings were compared for foliar anthracnose control, yield, and profitability of fungicide use in grain sorghum over eight site-years in Virginia and North Carolina. Anthracnose severity was rated at the hard dough stage, and grain yield was determined at harvest. Every percent increase in disease severity resulted in yield losses of 27 to 85 kg/ha. Pyraclostrobin and pyraclostrobin plus fluxapyroxad reduced anthracnose (P < 0.01), and three applications resulted in less disease and greater yield compared with single applications (P < 0.01). However, three applications exceed the labeled maximum application for the fungicides and are not economical. Among single applications, boot or flowering timings reduced disease, and flowering applications resulted in the overall greatest yield. Results suggest that when disease onset occurs at or prior to boot, a single application of pyraclostrobin-containing fungicide at or just prior to flowering reduces anthracnose, protects yield, and increases income. However, when disease is absent or severity is low prior to flowering, fungicide application may not be profitable.
39
Alderman, Stephen C., Darrin L. Walenta, and Philip B. Hamm. "Timing of Occurrence of Claviceps purpurea Ascospores in Northeast Oregon." Plant Health Progress 11, no. 1 (January 2010): 2. http://dx.doi.org/10.1094/php-2010-1123-01-rs.
Full textAbstract:
Ergot, caused by Claviceps purpurea, is an important floral disease of grasses, characterized by sclerotium formation within the host flowers. To determine whether annual variation in ergot severity in Kentucky bluegrass is a result of ascospore density and/or timing of ascospore occurrence, Burkard 7-day volumetric spores traps were used to monitor ascospores of C. purpurea in each of two Kentucky bluegrass fields in the Grand Ronde Valley in northeastern Oregon between mid-May and late June, 2008-2010. Ascospores were typically trapped between midnight and 6:00 a.m. In 2008 and 2010, most ascospores were released prior to flowering in Kentucky bluegrass, corresponding to no observed ergot in 2008 and a low level of ergot in 2010. In 2009, ascospore release and pollination coincided, but few airborne ascospores were present, resulting in a low level of ergot. Similar ergot levels were observed in fungicide trials, suggesting that fungicides for ergot control were unnecessary. In years when there are few ascospores during flowering in Kentucky bluegrass, a reduction of up to two fungicide applications may be possible. Accepted for publication 2 November 2010. Published 23 November 2010.
40
Walter, M., F. O. Obanor, J. T. Smith, C. Ford, K. S. H. Boyd-Wilson, P. Haris-Virgin, and G. I. Langford. "Timing of fungicide application for Botrytis cinerea control in blackcurrant (Ribes nigrum)." New Zealand Plant Protection 60 (August 1, 2007): 114–22. http://dx.doi.org/10.30843/nzpp.2007.60.4635.
Full textAbstract:
Flower blight in blackcurrants caused by the fungus Botrytis cinerea has received little attention in New Zealand To determine the efficacy of a fungicide application in relation to the timing of infection fungicides were applied 5 3 and 1 day before as well as immediately after 1 2 and 5 days after an infection event Cyprodinil and fludioxonil (Switch) were chosen because of the translaminar systemic and protective mode of action Studies were conducted during the 2006 flowering season in the laboratory and in the field on commercial properties in Canterbury and Nelson Natural Botrytis flower inoculation and infection events were common during the 2006/07 production season Results suggest that timing of fungicide application is critical for B cinerea control in blackcurrants Protection of flowers was achieved with cyprodinil and fludioxonil applications from 3 days before to 3 days after an inoculation and/or infection event Reduction of flower infections resulted in increased fruit set
41
Gent, David H., Megan C. Twomey, Sierra N. Wolfenbarger, and Joanna L. Woods. "Pre- and Postinfection Activity of Fungicides in Control of Hop Downy Mildew." Plant Disease 99, no. 6 (June 2015): 858–65. http://dx.doi.org/10.1094/pdis-10-14-1004-re.
Full textAbstract:
Optimum timing and use of fungicides for disease control are improved by an understanding of the characteristics of fungicide physical mode of action. Greenhouse and field experiments were conducted to quantify and model the duration of pre- and postinfection activity of fungicides most commonly used for control of hop downy mildew (caused by Pseudoperonospora humuli). In greenhouse experiments, control of downy mildew on leaves was similar among fungicides tested when applied preventatively but varied depending on both the fungicide and the timing of application postinfection. Disease control decreased as applications of copper were made later after inoculation. In contrast, cymoxanil, trifloxystrobin, and dimethomorph reduced disease with similar efficacy when applied 48 h after inoculation compared with preventative applications of these fungicides. When fungicides were applied 72 h after inoculation, only dimethomorph reduced the sporulating leaf area similarly to preinoculation application timing. Adaxial chlorosis, necrosis, and water soaking of inoculated leaves, indicative of infection by P. humuli, were more severe when plants were treated with cymoxanil, trifloxystrobin, and dimethomorph 48 to 72 h after inoculation, even though sporulation was suppressed. Trifloxystrobin and dimethomorph applied 72 h after inoculation suppressed formation of sporangia on sporangiophores as compared with all other treatments. In field studies, dimethomorph, fosetyl-Al, and trifloxystrobin suppressed development of shoots with systemic downy mildew to the greatest extent when applied near the timing of inoculation, although the duration of preventative and postinfection activity varied among the fungicides. There was a small reduction in efficacy of disease control when fosetyl-Al was applied 6 to 7 days after inoculation as compared with protective applications. Trifloxystrobin had 4 to 5 days of preinfection activity and limited postinfection activity. Dimethomorph had the longest duration of protective activity. Percent disease control was reduced progressively with increasing time between inoculation and application of dimethomorph. These findings provide guidance to the use of fungicides when applications are timed with forecasted or post hoc disease hazard warnings, as well as guidance on tank-mixes of fungicides that may be suitable both for resistance management considerations and extending intervals between applications.
42
Akinsanmi, O. A., A. K. Miles, and A. Drenth. "Timing of Fungicide Applications for Control of Husk Spot Caused by Pseudocercospora macadamiae in Macadamia." Plant Disease 91, no. 12 (December 2007): 1675–81. http://dx.doi.org/10.1094/pdis-91-12-1675.
Full textAbstract:
Pseudocercospora macadamiae is an important pathogen of macadamia in Australia, causing a disease known as husk spot. Growers strive to control the disease with a number of carbendazim and copper treatments. The aim of this study was to consider the macadamia fruit developmental stage at which fungicide application is most effective against husk spot, and whether application of copper-only applications at full-size fruit developmental stage toward the end of the season contributed to effective disease control. Fungicides were applied to macadamia trees at four developmental stages in three orchards in two subsequent production seasons. The effects of the treatments on disease incidence and severity were quantified using area under disease progress curve (AUDPC) and logistic regression models. Although disease incidence varied between cultivars, incidence and severity on cv. A16 showed consistent differences between the treatments. Most significant reduction in husk spot incidence occurred when spraying commenced at match-head sized-fruit developmental stage. All treatments significantly reduced husk spot incidence and severity compared with the untreated controls, and a significant positive linear relationship (R2 = 73%) between AUDPC and severity showed that timing of the first fungicide application is important for effective disease control. Application of fungicide at full-size fruit stage reduced disease incidence but had no impact on premature fruit drop.
43
Seidl Johnson, Anna C., Stephen A. Jordan, and Amanda J. Gevens. "Efficacy of Organic and Conventional Fungicides and Impact of Application Timing on Control of Tomato Late Blight Caused by US-22, US-23, and US-24 Isolates of Phytophthora infestans." Plant Disease 99, no. 5 (May 2015): 641–47. http://dx.doi.org/10.1094/pdis-04-14-0427-re.
Full textAbstract:
Late blight, caused by Phytophthora infestans, is one of the most economically important diseases of potato and tomato worldwide. Repeated preventative application of fungicides is the primary means of control on susceptible solanaceous host crops. For organic production, fungicide choices are limited, and little efficacy data on noncopper options is available on which to base control recommendations. Twelve fungicides, including organic and conventional selections, were evaluated for both preventative and postinfection control of a single infection cycle of late blight caused by isolates representing three recently identified P. infestans clonal lineages (US-22, US-23, and US-24) using a detached tomato leaf assay. A subset of the most effective fungicides was also tested for preventative control of a single infection cycle of late blight caused by an isolate of US-23 on potted whole tomato plants under laboratory conditions. Fungicide applications made 2 days after inoculation failed to significantly control late blight on detached leaves in all treatments, with the exception of Bravo Ultrex (US-23 only) and Phostrol (US-22 only). Preventative fungicide applications of Bravo Ultrex, Ridomil Gold SL, Revus, Zonix, and low and high rates of EF400 significantly controlled late blight caused by US-22, -23, and -24 isolates. Additionally, preventative application of Phostrol significantly controlled late blight caused by the US-22 isolate; and Phostrol, low rate of Mycostat, and high rate of Champ significantly controlled late blight caused by the US-23 isolate. Late blight caused by the US-24 isolate was significantly reduced compared with US-22 and US-23 isolates for all fungicide treatments applied after inoculation, as well as for all preventative fungicide treatments, with the exception of Bravo, Ridomil, and Revus. In whole-potted-plant assays with the US-23 isolate, late blight was significantly controlled by preventative application of Bravo Ultrex, Ridomil Gold SL, and high rate of EF400; disease was not significantly controlled by Zonix, low rate of EF400, Phostrol, or low and high rates of Champ. Based on these results, it is anticipated that currently available fungicides with suitability to conventional and organic systems can effectively control late blight caused by new clonal lineages of P. infestans when applied preventatively and that late blight caused by the US-24 clonal lineage may require less fungicide use than US-22 or US-23 to mitigate disease.
44
Hill, C. B., C. R. Bowen, and G. L. Hartman. "Effect of Fungicide Application and Cultivar on Soybean Green Stem Disorder." Plant Disease 97, no. 9 (September 2013): 1212–20. http://dx.doi.org/10.1094/pdis-12-12-1191-re.
Full textAbstract:
Green stem disorder of soybean (Glycine max) has increasingly become a nuisance for soybean producers. The disorder is distinguished from other manifestations of delayed plant maturity by the delayed senescence of stems only, with normal pod ripening and seed maturation. The primary objective of the first study was to determine whether green stem disorder increased with a fungicide treatment. Field cages to isolate soybean plants to prevent insect interactions were used and treatments included maturity group (MG) II insensitive and sensitive soybean cultivars with or without fungicide applications. A secondary objective was to determine fungi potentially associated with the disorder. The results indicated significant elevation of the incidence of green stem disorder when using a fungicide. Species of Diaporthe or Phomopsis and Macrophomina phaseolina were more frequent in stems without the disorder, whereas species of Colletotrichum were found mostly in stems with the disorder. In another study, field experiments were conducted without cages in replicated field plots to compare the effects of fungicides with different chemistries and timing of fungicide application on incidence of green stem disorder using green stem disorder MG II- and MG III-sensitive and insensitive soybean cultivars. There was a significant increase in percentage of green stem disorder due to fungicide application, depending on fungicide chemistry, timing of application, year, location, and cultivar sensitivity to green stem disorder. Generally, Headline and Headline-Domark applications resulted in higher incidence of green stem disorder than Domark alone or the nonsprayed control, with over 50% incidence in many cases. Higher percent green stem disorder was significantly (P < 0.05) associated with higher yields in 11 of the 28 trials. From the results of this research, soybean producers should be aware of the possible risk that fungicide application may have in increasing incidence of green stem disorder. In addition, producers can help manage green stem disorder by selecting soybean cultivars reported to be consistently insensitive to the disorder.
45
Sapak, Z., M. U. Salam, E. J. Minchinton, G. P. V. MacManus, D. C. Joyce, and V. J. Galea. "POMICS: A Simulation Disease Model for Timing Fungicide Applications in Management of Powdery Mildew of Cucurbits." Phytopathology® 107, no. 9 (September 2017): 1022–31. http://dx.doi.org/10.1094/phyto-11-16-0413-r.
Full textAbstract:
A weather-based simulation model, called Powdery Mildew of Cucurbits Simulation (POMICS), was constructed to predict fungicide application scheduling to manage powdery mildew of cucurbits. The model was developed on the principle that conditions favorable for Podosphaera xanthii, a causal pathogen of this crop disease, generate a number of infection cycles in a single growing season. The model consists of two components that (i) simulate the disease progression of P. xanthii in secondary infection cycles under natural conditions and (ii) predict the disease severity with application of fungicides at any recurrent disease cycles. The underlying environmental factors associated with P. xanthii infection were quantified from laboratory and field studies, and also gathered from literature. The performance of the POMICS model when validated with two datasets of uncontrolled natural infection was good (the mean difference between simulated and observed disease severity on a scale of 0 to 5 was 0.02 and 0.05). In simulations, POMICS was able to predict high- and low-risk disease alerts. Furthermore, the predicted disease severity was responsive to the number of fungicide applications. Such responsiveness indicates that the model has the potential to be used as a tool to guide the scheduling of judicious fungicide applications.
46
Bowen, K. L., A. K. Hagan, M. Pegues, and J. Jones. "Yield Losses Due to Crown Rust in Winter Oats in Alabama." Plant Health Progress 17, no. 2 (January 2016): 95–100. http://dx.doi.org/10.1094/php-rs-16-0016.
Full textAbstract:
Crown rust is a common disease on winter oats in Alabama. While considered the most destructive disease of oats, little has been done in recent years, with current cultivars, to demonstrate yield losses due to crown rust. Field studies were conducted to determine the effect of fungicides and application timing on crown rust severity and yield. All fungicides reduced crown rust and improved yield. Two fungicide applications were better than a single fungicide application for reducing crown rust. Relative to yield, a single fungicide application during flag leaf development (FS 8-9) was better than a single application during head extension (FS 10.3). When compared with the non-treated control, significant yield gains were obtained with Tilt and Headline in all four years and Stratego YLD in three of four years. Fungicide programs resulted in a broad range of crown rust severities; disease levels were highly related to decreases in yield in each of four years. In two study years, ‘Coker 227’ was more damaged by crown rust, with about 10% yield loss for each unit disease, than was ‘Horizon 270,’ with 2.5 to 4.5% loss. However, in 2013, virulence patterns of the crown rust pathogen shifted and disease on Horizon 270 was greater than that on Coker 227; relative yield losses were also much lower in 2013. Accepted for publication 15 April 2016. Published 4 May 2016.
47
Ons, Lena, Dany Bylemans, Karin Thevissen, and Bruno P. A. Cammue. "Combining Biocontrol Agents with Chemical Fungicides for Integrated Plant Fungal Disease Control." Microorganisms 8, no. 12 (December 4, 2020): 1930. http://dx.doi.org/10.3390/microorganisms8121930.
Full textAbstract:
Feeding a rising population of currently 7.8 billion people globally requires efficient agriculture, which is preferably sustainable. Today, farmers are largely dependent on synthetic fungicides to avoid food losses caused by fungal diseases. However, the extensive use of these has resulted in the emergence of fungicide-resistant pathogens and concerns have been raised over the residual effects on the environment and human health. In this regard, biocontrol agents (BCAs) have been proposed as an alternative to standard fungicides but their disease management capacity is usually incomplete and heavily relies on uncontrollable environmental conditions. An integrated approach combining BCAs with fungicides, which is the focus of this review, is put forward as a way to reduce the fungicide doses to manage plant diseases and thereby their residue on harvested crops. In addition, such a strategy of combining antifungal treatments with different modes of action reduces the selection pressure on pathogens and thereby the chances of resistance development. However, to allow its large-scale implementation, further knowledge is needed, comprising timing, number and interval of repeated BCA applications and their compatibility with fungicides. The compatibility of BCAs with fungicides might differ when applied in a mixture or when used in alternation.
48
Groth, D. E. "Azoxystrobin Rate and Timing Effects on Rice Head Blast Incidence and Rice Grain and Milling Yields." Plant Disease 90, no. 8 (August 2006): 1055–58. http://dx.doi.org/10.1094/pd-90-1055.
Full textAbstract:
Growing blast susceptible rice (Oryza sativa) cultivars often requires farmers to use fungicides to prevent significant reductions in rice grain and milling yields. Studies were conducted to determine the optimum rate and rice growth stage for single or multiple applications of azoxystrobin to control blast (Pyricularia grisea). Azoxystrobin was applied foliarly to naturally infected field plots in 2001 to 2005 at rates of 0.11, 0.17, and 0.22 kg a.i. ha-1 at boot (B) and heading (H) or only at H growth stages, and at 0.17 kg a.i. ha-1 at 5 (H+5), 10 (H+10), and 15 (H+15) days after H and B with low or high blast pressure. Head blast incidence (percent heads infected) was assessed 1 to 2 weeks before harvest. A fungicide application made at H, H+5, and B+H significantly reduced blast incidence with high and low disease pressure, resulting in significantly higher grain and head rice milling yields compared with unsprayed plots with high blast pressure. There were no significant effects of fungicide rate on blast development or yield following the H, B+H, and H+5 applications. With fungicide applications made at B, H+10, and H+15 days postheading, rice had higher disease incidence, resulting in lower grain and milling yields compared with rice receiving a heading application.
49
McGrath, Margaret Tuttle. "Efficacy of Conventional Fungicides for Downy Mildew in Field-Grown Sweet Basil in the United States." Plant Disease 104, no. 11 (November 2020): 2967–72. http://dx.doi.org/10.1094/pdis-11-19-2382-re.
Full textAbstract:
Application of fungicides has been the main management practice for Peronospora belbahrii, which is the most important pathogen of sweet basil in the United States. Six replicated experiments were conducted between 2010 and 2016 with field-grown basil of a susceptible cultivar exposed to naturally occurring wind-dispersed sporangiospores of P. belbahrii to evaluate conventional fungicides registered for basil downy mildew in the United States and in development for this use. This project revealed the importance for successful management of using a preventive fungicide application schedule, maintaining a 7-day application interval, and using application equipment designed to provide thorough spray coverage to plants (drop nozzles). Fungicide efficacy was assessed based on incidence of symptomatic leaves rather than disease severity, which is stringent but realistic because there is zero tolerance for disease on fresh-market herbs. Most fungicides were tested as the formulated product marketed in the United States. Oxathiapiprolin was tested as experimental formulations. Its trade name is Orondis. Overall best control was achieved in 2016. Excellent control (99% based on AUDPC values) was obtained with four fungicide programs with oxathiapiprolin, Revus, and ProPhyt, indicating this combination of chemistry was more important than specific timing for each fungicide. Ranman applied in alternation with Revus plus K-Phite was not quite as effective (89% control); this treatment was ineffective in 2015 when the 7-day spray interval was not maintained. Best treatment in 2015 was Quadris applied in alternation with Revus plus oxathiapiprolin for two of three Revus applications. Two different alternations of these fungicides also were effective. But Quadris alternated with Revus was ineffective. When tested singly, the most effective fungicides in 2013 (listed in order based on AUDPC values) were Zampro, Revus, oxathiapiprolin, and Ranman. ProPhyt was effective in 2013 but not in 2012, when another phosphorous acid fungicide, K-Phite, also was ineffective. Only oxathiapiprolin and Zampro were effective in the 2012 experiment; Revus and Ranman were ineffective. Presidio was ineffective both years. Based on the results from this study, Orondis is the most effective fungicide among those evaluated for managing basil downy mildew, and Zampro is second. Neither were labeled for this use on field-grown basil as of June 2020. Ranman applied in alternation with Revus plus K-Phite, a commonly recommended program of labeled fungicides, provided very good control.
50
Bradley, Carl A., Richard C. Kenimer, Jordan M. Shockley, and Kiersten A. Wise. "Effect of Benzovindiflupyr + Azoxystrobin + Propiconazole Fungicide Applied at Different Growth Stages on Foliar Disease Severity, Grain Yield, and Economic Benefit of Hybrid Corn Grown in Kentucky." Plant Health Progress 21, no. 3 (January 1, 2020): 162–65. http://dx.doi.org/10.1094/php-12-19-0099-rs.
Full textAbstract:
Field trials were conducted across nine different environments in Kentucky in 2017 and 2018 that evaluated a fungicide containing benzovindiflupyr + azoxystrobin + propiconazole applied to hybrid corn (Zea mays) at the six-leaf collar stage (V6) or at silking (R1) and a sequential application timing (V6 + R1). Results indicated that treatments that included an R1 application provided the best foliar disease control and were the only treatments that preserved yields compared with the nontreated control. A single application at R1 did not differ from the sequential V6 + R1 application for disease control or yield response, suggesting that Kentucky corn growers likely can rely on a more cost-effective single fungicide application at R1 for foliar disease management and improve return on fungicide investment rather than making multiple applications at different timings.