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

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.

2014 ◽  
Vol 41 (1) ◽  
pp. 50-57 ◽  
Author(s):  
J. E. Woodward ◽  
T. B. Brenneman ◽  
R. C. Kemerait ◽  
A. K. Culbreath ◽  
N. B. Smith

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.


1994 ◽  
Vol 21 (2) ◽  
pp. 134-138 ◽  
Author(s):  
T. B. Brenneman ◽  
H. R. Sumner ◽  
L. R. Chandler ◽  
J. M. Hammond ◽  
A. K. Culbreath

Abstract Propiconazole (Tilt®) was applied to Florunner peanut by injection into irrigation water (chemigation) or as a foliar spray. At rates of 0.12-0.25 kg/ha of propiconazole control of both Rhizoctonia limb rot (Rhizoctonia solani AG-4) and stem rot (Sclerotium rolfsii) was inconsistent. Chemigation resulted in the lowest incidence of stem rot, but the incidence of stem rot was only 26% less than the control. Yields from plots receiving chemigation were greater than expected based on disease ratings, indicating that some effects of the fungicide were not being evaluated. Where foliar sprays of chlorothalonil were applied for late leaf spot (Cercosporidium personatum), supplemental applications of propiconazole via chemigation improved leaf spot control. However, substituting chemigated propiconazole for foliar sprays of chlorothalonil consistently resulted in more severe leaf spot and, in one year, decreased yields. Propiconazole is most effective against leaf spot when applied as a foliar spray, whereas chemigation applications provide optimum efficacy against soilborne pathogens of peanut.


Plant Disease ◽  
2019 ◽  
Vol 103 (11) ◽  
pp. 2781-2785
Author(s):  
J. R. Standish ◽  
A. K. Culbreath ◽  
W. D. Branch ◽  
T. B. Brenneman

Peanut (Arachis hypogaea L.) producers rely on costly fungicide programs to manage stem rot, caused by Sclerotium rolfsii. Planting disease-resistant cultivars could increase profits by allowing for the deployment of less-expensive, lower-input fungicide programs. Field experiments were conducted to characterize stem rot and early and late leaf spot (caused by Passalora arachidicola and Nothopassalora personata, respectively), yield, and overall profitability of cultivars Georgia-06G (stem-rot-susceptible) and Georgia-12Y (stem-rot-resistant) as influenced by seven commercial fungicide programs. Stem rot incidence was consistently lower on Georgia-12Y for all fungicides when compared with Georgia-06G and was lowest for both cultivars in plots treated with prothioconazole plus a tank mixture of penthiopyrad and tebuconazole. Leaf spot severity was similar for both the resistant and susceptible cultivars, and the greatest reduction occurred in plots treated with prothioconazole plus a tank mixture of penthiopyrad and tebuconazole. Fungicide programs gave similar yield and net return on Georgia-12Y; however, plots of Georgia-06G treated with prothioconazole plus a tank mixture of penthiopyrad and tebuconazole had the greatest yield and net return. Yields and economic return from the highest level of fungicide inputs on Georgia-06G were numerically less than those of Georgia-12Y treated with only chlorothalonil. These results show the value of fungicides in peanut disease management with susceptible cultivars, as well as the benefits of planting stem-rot-resistant cultivars in high-risk situations.


2010 ◽  
Vol 37 (2) ◽  
pp. 129-136 ◽  
Author(s):  
A. K. Hagan ◽  
H. L. Campbell ◽  
K. L. Bowen ◽  
L. Wells ◽  
R. Goodman

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.


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 ◽  
...  

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.


EDIS ◽  
2017 ◽  
Vol 2017 (5) ◽  
Author(s):  
Michael J. Mulvaney ◽  
Robert (Bob) Kemerait ◽  
John D. Atkins ◽  
Nicholas S. Dufault

This report includes a summary of the 2016 foliar fungicide programs for control of early and late leaf spot and white mold (southern stem rot) in peanut at Jay, Florida. It shows the effectiveness of 13 fungicide programs for disease control. All programs contained active ingredients for the control of white mold (Sclerotium rolfsii) except the Bravo treatment (program #2), which was considered a control. These data represent only one year at one location, and readers are cautioned that test results should be considered over several locations and years before final conclusions are considered valid. These data are meant to serve as a guide in the selection of effective fungicide programs for peanut.


2000 ◽  
Vol 27 (2) ◽  
pp. 83-87 ◽  
Author(s):  
W. J. Grichar ◽  
B. A. Besler ◽  
A. J. Jaks

Abstract Field studies were conducted at 11 locations across south Texas from 1994 to 1997 to determine the activity of azoxystrobin against southern stem rot (Sclerotium rolfsii Sacc.), Rhizoctonia pod rot (Rhizoctonia solani Kuhn), early leaf spot (Cercospora arachidicola Hori) and late leaf spot [Cercosporidium personatum (Berk. & Curt.) Deighton]. Azoxystrobin at 0.22 to 0.45 kg/ha applied twice provided control of stem rot, Rhizoctonia pod rot, and leaf spot comparable to tebuconazole at 0.2 kg/ha applied four times. Peanut yield increases were evident with all fungicide treatments over the untreated check.


2010 ◽  
Vol 37 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Jay W. Chapin ◽  
James S. Thomas ◽  
Thomas G. Isleib ◽  
Frederick M. Shokes ◽  
William D. Branch ◽  
...  

Abstract Susceptibility to viral and fungal diseases is a major factor limiting profit in the production of virginia-type peanuts (Arachis hypogaea L.) in the South Carolina coastal plain. Field tests were conducted over a three-year period (2006–08) to evaluate the disease resistance of 47 experimental virginia-type breeding lines and eight cultivars. Relative to commercially available standards, cultivar Bailey (recently released by N. C. State Univ.), three sister lines (N03088T, N03089T, and N03090T), and N03091T were found to have consistently less susceptibility to tomato spotted wilt tospovirus; late leaf spot, Cercosporidium personatum (Berk. and Curt.) Deighton; and stem rot, Sclerotium rolfsii Sacc. The level of field resistance measured for these three diseases was comparable to that of a resistant runner-type cultivar, Georgia-03L. Yield was highly correlated with multiple disease resistance, and yield performance of some resistant lines exceeded the best commercial standard cultivars under reduced fungicide programs. Potential negative attributes of Bailey, its sister lines, and N03091T were a greater susceptibility to leafhopper injury, Empoasca fabae (Harris), and a relatively larger plant size at maturity, without well defined rows to facilitate digging. Other lines that demonstrated reduced susceptibility to both tomato spotted wilt and stem rot were N03005J and N02009. Although only evaluated in the last test year, five Univ. of Florida lines (FLMR7, FLMR9, FLMR12, FLMR14, and FLMR15) and Georgia-08V (recently released by the Univ. of Georgia) also showed some reduction in stem rot susceptibility relative to the standard (cultivar NC-V 11). Equally important, many experimental lines were identified with significantly greater disease susceptibility than current commercial cultivars. Under South Carolina production conditions, these lines would be poor candidates for advancement. Deployment of the multiple disease resistance found in these experimental cultivars offers several potential benefits beyond direct yield improvement: reduction of fungicide input costs for both foliar and soil disease control, prolonging the utility of currently available fungicides, and reduction of weather related harvest risk by allowing earlier initial planting dates.


EDIS ◽  
2017 ◽  
Vol 2017 (4) ◽  
Author(s):  
Keith W. Wynn ◽  
Nicholas S. Dufault ◽  
Rebecca L. Barocco

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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