Managing early leaf spot and stem rot with reduced fungicide inputs on disease-resistant peanut cultivars

2010 ◽  
Vol 37 (2) ◽  
pp. 129-136 ◽  
Author(s):  
A. K. Hagan ◽  
H. L. Campbell ◽  
K. L. Bowen ◽  
L. Wells ◽  
R. Goodman
Keyword(s):  
Leaf Spot ◽  
Production Systems ◽  
Production Costs ◽  
Stem Rot ◽  
Fungicide Application ◽  
Net Returns ◽  
Disease Resistant ◽  
Peanut Production ◽  
Peanut Cultivars ◽  
Study Application

Abstract Fungicide inputs are a costly but critical component of peanut production systems in the southeast U.S. Current strategies for reducing fungicide application numbers that are needed to control diseases on peanut include extending application intervals beyond a 2-wk schedule or implementation of a fungicide advisory, such as AU-Pnuts. In this study, fungicide programs with azoxystrobin, chlorothalonil, and tebuconazole, using different application schedules, were compared for the control of early leaf spot and stem rot. Application schedules were the standard 2-wk calendar interval, extended 3- and 4-wk intervals, and applications were made according to the AU-Pnuts leaf spot advisory. Studies were conducted on the disease resistant cultivars DP-1 in 2003 and C-99R in 2004 and 2005. The numbers of fungicide applications for the 2, 3, and 4-wk schedules were 7, 5, and 4, respectively, in 2003 and 2004, and were 6, 5, and 4, respectively, in 2005. One less fungicide application was scheduled according to AU-Pnuts than with the 2-wk calendar schedule in all three years, yet final early leaf spot levels with these schedules were similar in 2 of 3 years. With one fewer fungicide application, the 3-wk schedule had higher leaf spot levels than the AU-Pnuts advisory in 2003 and 2004. Further, when application intervals were extended from 2 wk to 3 or 4-wk intervals, a significant increase in early leaf spot was noted in two of three years. Despite these differences in early leaf spot severity, application schedule had limited impact on yield in this study. Application interval also had little impact on stem rot incidence, but incidence of this disease was lower with the azoxystrobin than chlorothalonil programs in 2 of 3 years. The azoxystrobin program significantly increased yield in 2 of 3 years compared with the chlorothalonil or tebuconazole programs. Yield was also higher for the tebuconazole compared with chlorothalonil programs in 2 of 3 years. When fungicide product and application costs were calculated, and those and other typical peanut production costs were deducted from estimated returns based on actual yields, the resulting net returns did not significantly differ among fungicide programs or application schedules.

On-Farm Evaluations of Reduced Input Fungicide Programs in Peanut Fields with Low, Moderate, or High Levels of Disease Risk

2014 ◽  
Vol 41 (1) ◽  
pp. 50-57 ◽  
Author(s):  
J. E. Woodward ◽  
T. B. Brenneman ◽  
R. C. Kemerait ◽  
A. K. Culbreath ◽  
N. B. Smith
Keyword(s):  
Leaf Spot ◽  
Cultural Practices ◽  
Disease Risk ◽  
Sclerotium Rolfsii ◽  
Stem Rot ◽  
Cercospora Arachidicola ◽  
Production Region ◽  
Net Returns ◽  
Peanut Production ◽  
On Farm

ABSTRACT In 2003, 2004, and 2005 standard and reduced input fungicide programs were evaluated throughout the peanut production region of Georgia for control of early leaf spot (Cercospora arachidicola), late leaf spot (Cercosporidium personatum), and southern stem rot (Sclerotium rolfsii). Disease risk was determined for each field based on the cultural practices implemented and ranged from low to high. Six to eight fungicide applications were made in the standard programs, versus three to six applications in reduced programs. Leaf spot ratings were higher for the reduced programs in five of the fourteen trials with substantial defoliation occurring in one trial. Overall, southern stem rot control for the reduced programs was equal to or better than that for the standard program, which could be attributed to the differences in fungicide selection or timing. Pod yields for the reduced programs were equal to or greater than the standard programs in all but one trial. Net returns were higher for the reduced programs in half of the trials; however, the reduced program resulted in lower net returns in one trial in 2004. Our results indicate that reduced input fungicide programs can be used to adequately manage fungal diseases of peanut without compromising yield or profitability, and that the use of cultivars with moderate levels of disease resistance may enhance disease control.

Soil-Borne Pests of Peanut in Growers' Fields with Different Cropping Histories in Alabama1

1996 ◽  
Vol 23 (1) ◽  
pp. 36-42 ◽  
Author(s):  
K. L. Bowen ◽  
A. K. Hagan ◽  
J. R. Weeks
Keyword(s):  
Aspergillus Flavus ◽  
Meloidogyne Incognita ◽  
Leaf Spot ◽  
Sclerotium Rolfsii ◽  
Stem Rot ◽  
Peanut Seed ◽  
Control Programs ◽  
Aflatoxigenic Fungi ◽  
Peanut Production ◽  
Seed Invasion

Abstract Pest levels and yields of peanut were monitored in growers' fields in 1991 through 1993. Yields ranged from 2085 to 6440 kg/ha and averaged 3947 kg/ha over the 3 yr. Incidence of southern stem rot (SSR) (caused by Sclerotium rolfsii) averaged 7.6 foci (up to 30 cm in length) per 30.5 m row and ranged from 0 to 31.0 foci. Peanut yield tended to be inversely related to incidence of SSR and directly related to the number of years between peanut crops. Incidence of SSR was inversely related to number of years between peanut crops and was consistently greater in fields cropped to peanut every other year compared to other fields with less intensive peanut production. Yields obtained from irrigated fields averaged 11.4% greater than those without irrigation. Leaf spot control programs used by growers provided consistent levels of control. Peanut seed invasion by aflatoxigenic fungi and plant damage by larvae of the lesser cornstalk borer (Elasmopalus lignosellus) generally were low. Seed invasion by Aspergillus flavus-type fungi was positively correlated (P < 0.05) with damage due to lesser cornstalk borer in 1993. Juvenile populations of root knot nematodes (Meloidogyne incognita) were positively correlated (P < 0.001) with incidence of SSR in 1992.

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

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.

Seeding Rate and Planting Date Impacts Stand Density, Diseases, and Yield of Irrigated Peanuts

2015 ◽  
Vol 16 (2) ◽  
pp. 63-70 ◽  
Author(s):  
A. K. Hagan ◽  
H. L. Campbell ◽  
K. L. Bowen ◽  
L. Wells
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Stand Density ◽  
Planting Date ◽  
Stem Rot ◽  
Spot Intensity ◽  
Seeding Rate ◽  
Tomato Spotted Wilt ◽  
Peanut Cultivars

Release of peanut cultivars with enhanced tomato spotted wilt (TSW) resistance along with the decline in the incidence of this disease gives Alabama producers the option of earlier planting of irrigated peanuts to optimize farm operations and lower seeding rates to reduce input costs. Mid-April and mid-May plantings of the cvs. Florida-07, Georgia-06G, and Georgia Green at 6.6, 9.8, 13.1, and 19.7 seed/m were monitored over three years for TSW, stem rot, and leaf spot diseases as well as yield. Despite low TSW pressure and lack of a seeding rate response, disease incidence was higher in Georgia Green than Florida-07 and Georgia-06G with higher TSW indices noted for the April than May plantings of the former but not latter two cultivars. While not impacted by planting date, stem rot incidence, which was higher at 13.1 and 19.7 than 6.6 seed/m, was lower on Florida-07 than Georgia-06G and Georgia Green with the latter proving most susceptible. Although leaf spot intensity was not impacted by seeding rate, disease ratings were higher for May than April plantings, with Florida-07 and Georgia-06G having lower leaf spot ratings than Georgia Green in two of three study years. While planting date did not impact yield in two of three years, higher yields were recorded at 13.1 and 19.7 than 6.6 seed/m, with Florida-07 and Georgia-06G having higher yields than Georgia Green. Accepted for publication 16 February 2015. Published 20 April 2015.

scholarly journals Use of Resistant Cultivars and Reduced Fungicide Programs to Manage Peanut Diseases in Irrigated and Nonirrigated Fields

Plant Disease ◽  
2008 ◽  
Vol 92 (6) ◽  
pp. 896-902 ◽  
Author(s):  
J. E. Woodward ◽  
T. B. Brenneman ◽  
R. C. Kemerait ◽  
N. B. Smith ◽  
A. K. Culbreath ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Field Experiments ◽  
Production Systems ◽  
Sclerotium Rolfsii ◽  
Stem Rot ◽  
Management Systems ◽  
Cercospora Arachidicola ◽  
Spot Intensity ◽  
Economic Returns ◽  
Irrigation Effects

Field experiments were conducted in 2004 and 2005 to evaluate the response of several peanut cultivars to standard and reduced-input fungicide programs under production systems which differed in the duration of crop rotation, disease history within a field, or in the presence or absence of irrigation. Effects on early leaf spot (caused by Cercospora arachidicola), late leaf spot (caused by Cercosporidium personatum), and southern stem rot (caused by Sclerotium rolfsii), pod yields, and economic returns were assessed. Standard fungicide programs were similar for both sets of experiments and included applications of pyraclostrobin, tebuconazole, azoxystrobin, or chlorothalonil. Reduced-fungicide programs, comprising combinations of the aforementioned fungicides, resulted in two and four applications for the cultivar and irrigation experiment, respectively. Two additional programs (a seven-spray chlorothalonil and a nontreated control) were included in the cultivar experiment. Fungicide programs provided adequate levels of leaf spot suppression, and stem rot incidence was similar among fungicide programs within the two management systems. In the cultivar experiment, returns were significantly lower for the reduced program compared with the full program and seven-spray chlorothalonil program; however, they were significantly higher than the nontreated control. Significant differences in leaf spot, stem rot, and yield were observed among cultivars in both experiments. Overall, leaf spot intensity was lowest for the cvs. Georgia-03L and Georgia-01R and greatest for Georgia Green and Georgia-02C. Georgia-03L, Georgia-02C, and AP-3 consistently had lower incidence of stem rot than the other cultivars. Pod yields for all cultivars were equivalent to or greater than Georgia Green in both experiments; however, the performance of reduced-fungicide programs was inconsistent.

scholarly journals ECONOMIC ANALYSIS OF THREE TOMATO PRODUCTION SYSTEMS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 664e-664
Author(s):  
R.G. Brumfield ◽  
F.E. Effiom ◽  
S. Reiners
Keyword(s):  
Pest Management ◽  
Production Systems ◽  
Cropping Systems ◽  
Production Costs ◽  
The Other ◽  
Conventional System ◽  
Labor Costs ◽  
Tomato Production ◽  
Net Returns ◽  
Two Systems

Fresh tomatoes grown under three production cropping systems at the Rutgers University's Snyder Research and Extension Farm were compared for differences in yields, gross revenues, production costs and net returns. Maximum marketable yields were obtained using the Integrated Pest Management (IPM) system, followed closely by the conventional system. Yields of the organic plots were only 54 percent of the conventional yield. However, the organic plots yielded only 17 percent culls whereas the IPM plots yielded 37 percent culls. Fifty-two percent of the organic tomatoes were U.S. Number Ones, while only one third of the produce from the other two systems were U.S. Number One grade. Organic plots had lower chemical costs, but substantially higher labor costs than the other two systems.

Implications of fungicide application timing and post-spray irrigation on disease control and peanut yield

2011 ◽  
Vol 38 (1) ◽  
pp. 48-56 ◽  
Author(s):  
J. Augusto ◽  
T. B. Brenneman
Keyword(s):  
Disease Control ◽  
Leaf Spot ◽  
Stem Rot ◽  
Systemic Fungicide ◽  
Cercospora Arachidicola ◽  
Application Timing ◽  
Fungicide Application ◽  
Positive Effects ◽  
Spray Irrigation ◽  
Night And Day

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.

scholarly journals Comparison of Fungicide Programs for the Control of Early Leaf Spot and Southern Stem Rot on Selected Peanut Cultivars1

2004 ◽  
Vol 31 (1) ◽  
pp. 22-27 ◽  
Author(s):  
A. K. Hagan ◽  
M. E. Rivas-Davila ◽  
K. L. Bowen ◽  
L. Wells
Keyword(s):  
Disease Control ◽  
Leaf Spot ◽  
Partial Resistance ◽  
Stem Rot ◽  
Yield Response ◽  
Peanut Cultivars ◽  
Better Than

Abstract Azoxystrobin, tebuconazole, pyraclostrobin, chlorothalonil + flutolanil, and chlorothalonil fungicide programs were evaluated on selected peanut cultivars for the control of early leaf spot (ELS) and southern stem rot (SSR) in 2000, 2001, and 2002. A peanut-cotton-peanut rotation was followed and the plots were irrigated as needed. Virugard and Georgia Green were planted in all 3 yr. The late-maturing line Southern Runner was planted only in 2000 and was replaced with Florida C-99R in 2001 and 2002. Since the ranking of fungicide programs for ELS and SSR control and yield response was similar over peanut cultivars, data for each variable in 2000, 2001, and 2002 were pooled. The 0.34-kg ai/ha azoxystrobin and pyraclostrobin programs gave better ELS control than the season-long chlorothalonil standard in 1 yr. However, SSR control and yield response to pyraclostrobin was similar to the chlorothalonil standard. Significant reductions in SSR damage and higher yields were obtained with 0.34-kg ai/ha azoxystrobin program in all 3 yr. When compared to the chlorothalonil standard, the 0.47-kg ai/ha azoxystrobin program gave superior SSR control in 2000 and 2001, but significantly better ELS control and higher yield were obtained only in 2001. Tebuconazole-treated peanuts had similar ELS ratings to those recorded for the chlorothalonil standard and azoxystrobin programs in 2000 and 2001, but the ELS ratings for the former program were significantly higher in 2002. While tebuconazole reduced SSR damage compared with chlorothalonil alone, the azoxystrobin and chlorothalonil + flutolanil programs controlled SSR significantly better than tebuconazole in at least 1 yr. Also, the 0.34-kg ai/ha azoxystrobin program significantly increased yield above that of the chlorothalonil standard more consistently than did tebuconazole. Relatively few differences in disease control or yield response were noted between the two chlorothalonil + flutolanil programs, but both increased yield above that of the chlorothalonil standard. By maturing about 2 wk before Georgia Green, Virugard may have escaped some ELS and SSR damage, which may have contributed to its higher yield. There are indications that the late-maturing Florida C-99R has partial resistance to ELS but not SSR. Georgia Green proved more susceptible to both diseases than Virugard or Florida C-99R but no peanut cultivar produced consistently higher yields.

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