Application Rate and Treatment Interval Influence the Efficacy of Heritage Fungicide for the Control of Alternaria Leaf Spot on Marigold

Abstract Efficacy of Heritage 50WG (azoxystrobin) over a range of application rates and treatment intervals was compared with Daconil Weather Stik 6F (chlorothalonil) and Eagle 40W (myclobutanil) for the control of Alternaria leaf spot (Alternaria tagetica) in a simulated landscape planting of marigold in southwest Alabama. When applied at 2-week intervals, all rates of Heritage 50WG gave better disease control in all four years than Daconil Weather Stik 6F or Eagle 40W, applied on the same schedule. In two of three years, weekly applications of Daconil Weather Stik 6F decreased Alternaria leaf spot severity compared with the non-fungicide treated control, but when applied at 2-week intervals, disease levels were similar to the non-fungicide treated control in two of four years. Typically, Alternaria leaf spot intensified when Heritage 50WG application rates declined from 0.16 to 0.04 g ai·liter−1 and treatment intervals increased from 2-to 4-weeks. At the 0.04 g ai·liter−1 rate of Heritage 50WG, disease control was usually better at the 2-than at the 3-and, particularly, 4-week treatment schedule. Regardless of the level of disease pressure, Heritage 50WG at 0.08 and 0.16 g ai·liter−1 when applied at 3-week intervals consistently gave effective control of Alternaria leaf spot on marigold.

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Field Evaluation of Reduced Rate Brassicaceae Seed Meal Amendment and Rootstock Genotype on the Microbiome and Control of Apple Replant Disease

Phytopathology ◽

10.1094/phyto-02-19-0045-r ◽

2019 ◽

Vol 109 (8) ◽

pp. 1378-1391 ◽

Cited By ~ 7

Author(s):

Likun Wang ◽

Mark Mazzola

Keyword(s):

Disease Control ◽

Growing Season ◽

Application Rate ◽

Soil Fumigation ◽

Seed Meal ◽

Effective Control ◽

Apple Replant Disease ◽

Replant Disease ◽

Application Rates ◽

Reduced Rate

An orchard field trial was conducted to assess the utility of reduced rate Brassicaceae seed meal (SM) amendment in concert with specific rootstock genotypes for effective control of apple replant disease. Three amendment rates of a 1:1 formulation of Brassica juncea-Sinapis alba SM were compared with preplant 1,3-dichloropropene/chloropicrin soil fumigation for disease control efficacy. When applied at the highest rate (6.6 t ha−1) in the spring of planting, SM caused significant phytotoxicity and tree mortality, which was higher for Gala/M.26 than for Gala/G.41 but was not observed at SM application rates of 2.2 or 4.4 t ha−1. SM treatment resulted in growth and yield increases of Gala/M.26 and Gala/G.41 trees in a manner similar to the fumigation treatment and significantly greater than the no treatment control. Tree growth in soils treated with SM at 4.4 t ha−1 was similar or superior to that obtained with SM at 6.6 t ha−1 and superior to that attained at an SM application rate of 2.2 t ha−1. Soil fumigation and all SM treatments reduced Pratylenchus penetrans root infestation relative to the control treatment at the end of the initial growing season. Lesion nematode root densities in the fumigation treatment, but not SM treatments, rapidly recovered and were indistinguishable from the control at the end of the second growing season. Soil fumigation and all SM treatments significantly suppressed Pythium spp. root infection relative to the control. Trees grafted to rootstock G.41 possessed lower P. penetrans root densities relative to trees grafted to rootstock M.26. One year after planting, composition of microbial communities from SM-amended soils was distinct from those detected in control and fumigated soils, and the differences were amplified with increasing SM application rate. Specific fungal and bacterial phyla associated with suppression of plant pathogens were more abundant in SM-treated soil relative to the control, and they were similar in abundance in 4.4- and 6.6-t ha−1 SM treatments. Findings from this study demonstrated that use of the appropriate apple rootstock genotype will allow for effective replant disease control at SM application rates significantly less than that utilized previously (6.6 t ha−1).

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Impact of Application Rate and Treatment Interval on the Efficacy of Pyraclostrobin in Fungicide Programs for the Control of Early Leaf Spot and Southern Stem Rot on Peanut1

Peanut Science ◽

10.3146/pnut.30.1.0006 ◽

2003 ◽

Vol 30 (1) ◽

pp. 27-34 ◽

Cited By ~ 5

Author(s):

A. K. Hagan ◽

H. L. Campbell ◽

K. L. Bowen ◽

L. Wells

Keyword(s):

Disease Control ◽

Leaf Spot ◽

Application Rate ◽

Stem Rot ◽

Treatment Interval ◽

Strobilurin Fungicide

Abstract In 1999, 2000, and 2001, efficacy of the strobilurin fungicide pyraclostrobin (Headline F500) for the control of early leaf spot and southern stem rot was compared to that of standard fungicide programs on peanut cv. Georgia Green produced under irrigation. When applied at 2 wk intervals in 1999 and 2001, programs that included pyraclostrobin at rates ranging from 0.08 to 0.22 kg ai/ha gave better control of early leaf spot than the recommended season-long chlorothalonil program and were at least as efficacious against this disease as tebuconazole and azoxystrobin. The level of early leaf spot control provided by 0.08 to 0.16 kg ai/ha of pyraclostrobin applied every 3 wk and by chlorothalonil at the recommended 2 wk interval was similar. In all 3 yr, incidence of southern stem rot on peanut treated with pyraclostrobin alone, tank-mixed with flutolanil, or alternated with tebuconazole was significantly below damage levels recorded in plots treated with chlorothalonil alone and was usually comparable to the level of disease control obtained with recommended tebuconazole, flutolanil, or azoxystrobin programs. Compared to chlorothalonil alone, yields of the pyraclostrobin-treated peanuts were significantly greater in 2000 and 2001 and generally did not significantly differ from those yields recorded with the tebuconazole, flutolanil, or azoxystrobin programs. While pyraclostrobin often gave similar southern stem rot control over a range of treatment intervals, the most consistent yield gains were obtained when this fungicide was applied every 2 wk.

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Biological Control of Alternaria Leaf Spot Caused by Alternaria spp. in Jerusalem Artichoke (Helianthus tuberosus L.) under Two Fertilization Regimes

Plants ◽

10.3390/plants8110463 ◽

2019 ◽

Vol 8 (11) ◽

pp. 463 ◽

Cited By ~ 1

Author(s):

Wanalai Viriyasuthee ◽

Sanun Jogloy ◽

Weerasak Saksirirat ◽

Suwita Saepaisan ◽

Mark L. Gleason ◽

...

Keyword(s):

Disease Control ◽

Leaf Spot ◽

Jerusalem Artichoke ◽

Control Methods ◽

Alternaria Leaf Spot ◽

Resistant Varieties ◽

Khon Kaen ◽

Control Application ◽

Resistant Genotypes ◽

Reduce Disease Severity

The objectives of this study were to evaluate the efficacy of integrating resistant genotypes of Jerusalem artichoke with Trichoderma harzianum isolate T9 to control Alternaria leaf spot caused by Alternaria spp. under two fertilization regimes and to determine whether T9 application induced chitinase and β-1,3-glucanase activity in Jerusalem artichoke leaves. Six Jerusalem artichoke varieties (resistant varieties JA15, JA86, and JA116 and susceptible varieties HEL246, HEL293, and JA109) and three disease control methods (a non-inoculated control, application of T. harzianum T9, and fungicide sprays (propiconazole at a rate of 30 mL/20 L of water, 375 ppm)) was conducted in two separate trials (different fertilization regimes) at the experimental farm of the Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand. Resistant genotypes controlled Alternaria leaf spot effectively. Application of Trichoderma showed low efficacy to control Alternaria leaf spot, but in specific susceptible genotypes—HEL246 and HEL293—the application of Trichoderma could reduce disease severity up to 10%. The application of Trichoderma was associated with a rise in production of chitinase and β-1,3-glucanase in HEL246 seedlings. The number of Trichoderma propagules in soil, as well as the extent of colonization of roots and leaves, were monitored. The results indicated that application of Trichoderma had higher propagules than non-inoculated control. Neither varietal resistance nor the disease control methods used in this study impacted the yield or yield components of Jerusalem artichoke.

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Calendar and AU-Pnuts Advisory Programs Compared for Leaf Spot Diseases and Rust Control on Peanut in Southwest Alabama

Plant Health Progress ◽

10.1094/php-2006-1110-01-rs ◽

2006 ◽

Vol 7 (1) ◽

pp. 3

Author(s):

A. K. Hagan ◽

H. L. Campbell ◽

K. L. Bowen ◽

M. Pegues

Keyword(s):

Disease Control ◽

Leaf Spot ◽

Weather Conditions ◽

Treatment Schedule ◽

Advisory Programs ◽

Fungicide Application ◽

Leaf Spots ◽

Production Area ◽

Peanut Production ◽

Rain Events

Peanut production acreage has increased substantially in southwest Alabama in the past several years. Since prevailing weather conditions in this newer production area are conducive to peanut diseases, primarily due to frequent rainfall during summer months, a 2-week calendar fungicide treatment schedule is considered essential to controlling leaf spot diseases and rust in order to optimize yields. In 2003, 2004, and 2005, extended calendar application intervals and the AU-Pnuts leaf spot advisory were compared with the recommended 2-week calendar schedule for peanut disease control on partially disease-resistant peanut cultivars (DP-1 in 2003 and Florida C99R in 2004 and 2005). Fungicide programs included recommended rates of azoxystrobin, chlorothalonil, and tebuconazole. Numbers of fungicide applications for the 2-, 3-, and 4-week calendar schedule treatments were 7, 5, and 4, respectively in each year. Fungicide applications made according to AU-Pnuts are based on rain events and resulted in 5 sprays in 2003 and 7 sprays in 2004 and 2005. Fungicide application schedule had a significant impact on leaf spots, rust, southern stem rot and yield in at least two of the three study years. Results indicate that recommendations for the 2-week fungicide application schedule should be maintained in this area. Fungicide program also had a consistent effect on measured variables, with the azoxystrobin program providing better disease control and higher yields. Accepted for publication 16 August 2006. Published 10 November 2006.

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Impact of Application Rate and Interval on the Control of Powdery Mildew and Cercospora Leaf Spot on Bigleaf Hydrangea with Azoxystrobin

Journal of Environmental Horticulture ◽

10.24266/0738-2898-22.2.58 ◽

2004 ◽

Vol 22 (2) ◽

pp. 58-62 ◽

Cited By ~ 2

Author(s):

A. K. Hagan ◽

J. W. Olive ◽

J. Stephenson ◽

M. E. Rivas-Davila

Keyword(s):

Powdery Mildew ◽

Leaf Spot ◽

Application Rate ◽

Cercospora Leaf Spot ◽

Thiophanate Methyl ◽

Hydrangea Macrophylla ◽

Application Rates ◽

Erysiphe Polygoni ◽

Causal Fungus ◽

Paraffinic Oil

Abstract Efficacy of azoxystrobin (Heritage 50W™) was assessed over a range of application rates and intervals for the control of powdery mildew (Erysiphe polygoni) and Cercospora leaf spot (Cercospora hydrangea) on bigleaf hydrangea (Hydrangea macrophylla) ‘Nikko Blue’. Rooted hydrangea cuttings were transplanted in a pine bark/peat mixture. In 1998 and 1999, azoxystrobin at 0.16 g ai/liter and 0.32 g ai/liter, as well as 0.24 g ai/liter myclobutanil (Eagle 40W™) and 0.84 g ai/liter thiophanate methyl (3336 4.5F™), greatly reduced the incidence of powdery mildew compared with the untreated control where 75% of the leaves of were infected by the causal fungus. When applied at 1-, 2-, and 3-week intervals, both rates of azoxystrobin were equally effective in both years in preventing the development of powdery mildew on bigleaf hydrangea. In 1998, all fungicides except for thiophanate methyl protected bigleaf hydrangea from Cercospora leaf spot. In the last two trials, the incidence of powdery mildew increased significantly as the application rate for azoxystrobin decreased from 0.16 to 0.04 g ai/liter and the application interval was lengthened from 1 to 3 weeks. In general, all rates of azoxystrobin applied on a 3-week schedule failed to provide the level of powdery mildew control needed to produce quality bigleaf hydrangea for the florist and landscape market. When applied at 2-week intervals, myclobutanil was equally or more effective in controlling powdery mildew than any rate of azoxystrobin applied on the same schedule. When compared to the untreated controls, significant reductions in the incidence of powdery mildew on bigleaf hydrangea were obtained with weekly applications of paraffinic oil. No symptoms of phytotoxicity were associated with the use of any of the fungicides screened.

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ALTERNARIA LEAF SPOT DISEASE CONTROL ON FABA BEAN IN EGYPT

Journal of Plant Protection and Pathology ◽

10.21608/jppp.2014.87881 ◽

2014 ◽

Vol 5 (1) ◽

pp. 119-130

Author(s):

Magda Behairy ◽

H. Sobhy ◽

M. Abbas ◽

Kh. Abada ◽

Medhat Mourad

Keyword(s):

Disease Control ◽

Faba Bean ◽

Leaf Spot ◽

Leaf Spot Disease ◽

Spot Disease ◽

Alternaria Leaf Spot

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Effect of Host Plant Resistance and Reduced Rates and Frequencies of Fungicide Application to Control Potato Late Blight

Plant Disease ◽

10.1094/pdis.2001.85.10.1113 ◽

2001 ◽

Vol 85 (10) ◽

pp. 1113-1118 ◽

Cited By ~ 33

Author(s):

W. W. Kirk ◽

K. J. Felcher ◽

D. S. Douches ◽

J. Coombs ◽

J. M. Stein ◽

...

Keyword(s):

Late Blight ◽

Field Experiments ◽

Potato Late Blight ◽

Application Rate ◽

Effective Control ◽

Michigan State University ◽

State University ◽

Breeding Lines ◽

Application Rates ◽

Commercial Potato

Field experiments were conducted during 1998 to 2000 to determine the response of commercial potato cultivars and advanced breeding lines (ABL) differing in susceptibility to foliar late blight (caused by Phytophthora infestans) to reduced rates and frequencies of residual, contact fungicide applications. When environmental conditions were most favorable for the development of late blight, the lowest application rate of the fungicides chlorothalonil or fluazinam (33% of the manufacturers' recommended application rate [MRAR]) gave unsatisfactory control of potato late blight. Under conditions moderately conducive for late blight development, effective control was achieved with 33 to 66% MRAR with either fungicide. The Michigan State University advanced selection, MSG274-3, was the least susceptible ABL tested and, during 1998 to 2000, late blight was effectively managed using reduced rates of fungicides. Application rates of chlorothalonil (33 to 100% MRAR) significantly reduced late blight in the cultivar Snowden (5-day application interval) compared with the nontreated control; whereas, late blight was not effectively controlled in Snowden even at 100% MRAR of chlorothalonil at either 10- or 15-day application intervals in 1999 or 2000. The ABL MSG274-3 was the least susceptible of all cultivars and ABL used in this study, and required minimal chemical protection against late blight. The study demonstrates that ABL with reduced susceptibility to late blight can be managed with reduced fungicide rates and longer application intervals, thus offering more economical control of this disease.

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Instrata Fungicide Evaluated for Control of Cercospora Leaf Spot on Crapemyrtle

Journal of Environmental Horticulture ◽

10.24266/0738-2898.31.1.21 ◽

2013 ◽

Vol 31 (1) ◽

pp. 21-26

Author(s):

A. K. Hagan ◽

J. R. Arkidge

Keyword(s):

Disease Control ◽

Leaf Spot ◽

Application Rate ◽

Spot Intensity ◽

Cercospora Leaf Spot

Efficacy of Instrata™ 3.61E at rates of 0.54, 0.74, and 1.11 g ai·liter−1 was compared with recommended rates of the its component fungicides Daconil Ultrex 82.5WDG (chlorothalonil), Banner MAXX 1.3MEC (propiconazole), and Medallion 50W (fludioxonil) as well as Eagle 40W, Heritage 50WDG, and 3336 4.5F fungicide standards for the control of Cercospora leaf spot (Cercospora lythracearum) on field grown ‘Byer's Wonderful White’ crapemyrtle (Lagerstroemia indica) in 2007 and 2008. Efficacy of Instrata 3.61E for the control of Cercospora leaf spot on crapemyrtle was significantly impacted by application rate. Cercospora leaf spot intensity and defoliation AUDPC values as well as final disease ratings usually were lower for the 1.11 compared with the 0.54 g ai·liter−1 rates of Instrata 3.61E, while those of the 0.74 g ai·liter−1 rate were intermediate. The 1.11 g ai·liter−1 but not lower rates of Instrata 3.61E gave superior Cercospora leaf spot control in both study years when compared with the Daconil Ultrex 82.5WDG, Banner MAAX 1.3MEC, and Medallion 50W component fungicides with the two former fungicides providing some control in one of two years and the latter failing to reduce disease intensity or defoliation. Eagle 40W, Heritage 50WDG, and 3336 4.5F proved equally effective as the 1.11 g ai·liter−1 rate of Instrata 3.61E in controlling Cercospora leaf spot in 2007 but only Eagle 40W gave comparable disease control in 2008, while Heritage 50WDG and 3336 4.5F were generally less efficacious than all rates of Instrata 3.61E. In one of two years, better disease control was obtained with Eagle 40W when compared with the 3336 4.5F and Heritage 50WDG standards. Overall, efficacy of the 1.11 g ai·liter−1 rate of Instrata 3.61E for the control of Cercospora leaf spot on crapemyrtle was superior to not only the label rate of each component fungicide but also to the fungicide standards in one of two study years.

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OCCURRENCE OF ALTERNARIA LEAF SPOT DISEASE ON ALOE VERA AND ITS MANAGEMENT

Pakistan Journal of Phytopathology ◽

10.33866/phytopathol.031.01.0396 ◽

2019 ◽

Vol 31 (1) ◽

pp. 75-80

Author(s):

Muhammad M Rasheed ◽

Amer Habib ◽

Mustansar Aslam ◽

Zeeshan Mansha ◽

Abdul Rehman ◽

...

Keyword(s):

Disease Control ◽

Plant Extracts ◽

Leaf Spot ◽

Mycelial Growth ◽

Disease Incidence ◽

Aloe Vera ◽

Leaf Spot Disease ◽

Dry Rot ◽

Alternaria Leaf Spot

Aloe vera is a valuable medicinal crop of the world. It suffers from several diseases but among them alternaria leaf spot and dry rot is most serious fungal disease which effects the commercial production and quality losses to Aloe vera. A survey was conducted to estimate the prevalence of dry rot disease in different nurseries located in urban areas of Faisalabad. During this survey maximum disease incidence was recorded in Horti club nursery (100%) and minimum disease incidence recorded at Faiz baho nursery and Qadir baksh form (13.8%). Among in-vitro tested fungicides Score gives maximum mycelial growth inhibition (89.5%) and maximum disease control (17.7%) as compared to control and other tested chemicals. Among in-vitro tested plant extracts Neem gives maximum mycelial growth inhabitation (41.2%) and in green house gives 14.2% disease control. Out of four tested fungicides and plant extracts Score and Neem gives best results against A. alternata mycelial growth and disease control.

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

EDIS ◽

10.32473/edis-pp334-2017 ◽

2017 ◽

Vol 2017 (4) ◽

Author(s):

Keith W. Wynn ◽

Nicholas S. Dufault ◽

Rebecca L. Barocco

Keyword(s):

Plant Pathology ◽

Disease Control ◽

Leaf Spot ◽

Fungal Disease ◽

White Mold ◽

Stem Rot ◽

Late Leaf Spot ◽

Fact Sheet ◽

On Farm ◽

Hamilton County

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

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