scholarly journals Effects of Row Pattern, Seeding Rate, and Inoculation Date on Fungicide Efficacy and Development of Peanut Stem Rot

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 273-278 ◽  
Author(s):  
L. E. Sconyers ◽  
T. B. Brenneman ◽  
K. L. Stevenson ◽  
B. G. Mullinix

Two field studies were conducted in 2000, 2001, and 2002 to determine the effects of row pattern (91.4-cm single or 20.3-cm twin) and seeding rate (single: 12.5, 17.4, or 22.6 seed m-1or twin: 6.2, 8.9, or 11.5 seed m-1) on peanut stem rot (Sclerotium rolfsii) development. The first study was conducted in a naturally infested field and relative efficacy of azoxystrobin (Abound 2.08 F, applied at a rate of 0.3 kg a.i. ha-1 at 60 and 90 days after planting [DAP]) also was evaluated. In this study, stem rot incidence was significantly greater (P < 0.05) in single rows planted at high seeding rates than in twin rows planted at any of the seeding rates. Row pattern did not affect azoxystrobin efficacy, and disease incidence was nearly half as much in twin rows treated with fungicide than incidence in single rows treated with fungicide. In the second field study, individual peanut plants in fumigated plots were inoculated once with S. rolfsii at 50, 70, or 90 DAP. Stem rot incidence at harvest was significantly greater on plants inoculated 50 DAP than plants inoculated 70 or 90 DAP. The incidence of spread to adjacent rows was higher in plots where plants were inoculated at 50 than at 90 DAP. Plants inoculated 90 DAP had less disease at harvest, but often developed more severe symptoms within the first week after inoculation compared with plants inoculated 50 or 70 DAP. Symptoms were more severe in single than in twin rows, and at the higher seeding rates. Data from these studies suggest that the physical spacing between plants is a critical factor in stem rot development both on individual plants and in plant populations.

1994 ◽  
Vol 21 (1) ◽  
pp. 16-19 ◽  
Author(s):  
G. Wehtje ◽  
R. Weeks ◽  
M. West ◽  
L. Wells ◽  
P. Pace

Abstract Variability of peanut (Arachis hypogaea L.) seedling spacing, and yield were compared for a conventional and a vacuum-type planter in field studies conducted in 1991 and 1992. Vacuum-type planters have an improved seed metering system and are considered to be more precise. This added precision may serve to compensate for lower than normal seeding rates. Seeding rates evaluated decreased in a step-wise manner from the normal range of 123 to 101 kg/ha, to a minimum of 34 kg/ha. Spacing between individual seedlings was measured after emergence. The occurrence of tomato spotted wilt (TSWV) and southern stem rot were also determined. In 1991 and across all seeding rates, variability in seedling spacing (i.e. standard deviation) was identical between the two planters. In 1992, at 3 of the five seeding rates (34,56, and 101 kg/ha) standard deviation was less with the vacuum planter. In both years yield and disease occurrence was influenced only by seeding rate, and was independent of planter type. TSWV was inversely related to seeding rate, the opposite relationship occurred with southern stem rot. Maximum yield was achieved with a seeding rate of 101 kg/ha.


2002 ◽  
Vol 29 (1) ◽  
pp. 66-71 ◽  
Author(s):  
S. L. Rideout ◽  
T. B. Brenneman ◽  
K. L. Stevenson

Abstract Southern stem rot (caused by the soilborne fungus Sclerotium rolfsii Sacc.) of peanut (Arachis hypogaea L.) traditionally has been assessed based on the percentage of infected 30.5-cm row segments, commonly referred to as disease incidence. Several alternative disease assessment methods were evaluated in four fungicide trials during the growing season (aboveground ratings) and immediately after peanut inversion (belowground ratings). Pearson's correlation coefficients compared disease assessments and yields for all trials. Across all disease assessment methods, belowground assessments at inversion showed a stronger correlation with yield than in-season aboveground assessments. Several of the alternative assessment methods showed a stronger negative correlation with yield than did the traditional disease incidence rating. However, none of the alternative methods were consistently more precise across all assessment dates and trials. There was a significant positive correlation between many of the alternative methods and the traditional disease incidence method. Furthermore, none of the alternative methods was better than the traditional method for detecting differences among fungicide treatments when subjected to ANOVA and subsequent Waller-Duncan mean separation tests (k-ratio = 100). Based on comparisons of the time required to assess disease intensity, the traditional disease assessment method was found to be the most time efficient method of those tested in this study.


1990 ◽  
Vol 17 (2) ◽  
pp. 65-67 ◽  
Author(s):  
T. B. Brenneman ◽  
W. D. Branch ◽  
A. S. Csinos

Abstract The susceptibility of 16 peanut (Arachis hypogaea L.) genotypes (eight Virginia and eight runner types) to southern stem rot (Sclerotium rolfsii Sacc.) was evaluated in field tests over three years. Mean disease incidence for all cultivars was 10.0, 15.4 and 16.4 disease loci per 12.2 m row and average yields were 3488, 2826 and 3569 kg/ha in 1986, 1987 and 1988, respectively. Disease incidence averaged 14.3 disease loci per 12.2 m of row for both market types. The mean yield for the eight Virginia types was 3287 kg/ha versus 3214 for the eight runner types. Culitvars within market types varied significantly in disease incidence and pod yield. Of the Virginia types, NC 6 and Florigiant were the most susceptible with NC 9, VA 81B and Early Bunch being the most resistant. Incidence of stem rot in runner cultivars was high except for Southern Runner and Langley which had about 50% less disease than the most susceptible entries. There was a highly significant correlation (P≤0.01) between yields and disease incidence all three years. Overall, Southern Runner had the lowest disease incidence and highest pod yield of any cultivar. Compared to Florunner, the current industry standard for runner types, Southern Runner had about 50% less disease and yields were 1346 kg/ha higher.


1989 ◽  
Vol 16 (1) ◽  
pp. 9-14 ◽  
Author(s):  
O. D. Smith ◽  
T. E. Boswell ◽  
W. J. Grichar ◽  
C. E. Simpson

Abstract Eight breeding lines, three parents, and the cultivar Florunner were compared under two levels of disease pressure induced by Sclerotium rolfsii Sacc., or Pythium myriotylum Drechs. at each of two locations for three years to ascertain the effectiveness of the host plant resistance to each pathogen. Varied disease pressures were created by application of fungicides and supplement of fungal inoculum. Mean Florunner pod yields varied more than 1000 kg/ha as a result of the S. rolfsii treatments but the yields of the resistant TxAG-3 were not affected. Disease incidence, as measured by frequency of S. rolfsii infection sites and diseased pods, was much higher for Florunner than TxAG-3. Breeding lines for which TxAG-3 was a parent sustained significant yield reductions. The disease incidence in these lines was higher than the resistant parent, equal or less than Tamnut 74, their other parent, and less than Florunner. The grades of TxAG-3 and its derivatives were lower than Florunner. Pod rot incidence differed for the P. myriotylum treatments but pod yields were not different. TxAG-3 and Toalson sustained less pod disease than Florunner and Tamnut 74. The percent of diseased pod tissue for one derivative of Toalson was lower than Toalson and TxAG-3, and that of one TxAG-3 derivative was equal to its best parent. The breeding lines varied in reaction to the two diseases and some lines showed considerable resistance to both organisms.


1994 ◽  
Vol 21 (2) ◽  
pp. 126-129 ◽  
Author(s):  
W. Carroll Johnson ◽  
Timothy B. Brenneman ◽  
Benjamin G. Mullinix

Abstract Field studies were conducted from 1991 through 1993 at Plains, GA to determine the effect of chloroacetamide herbicides and chlorimuron on incidence of stem rot in peanut. The experimental site had a cropping history of more than 25 yr in continuous plantings of peanut and extremely high incidence of stem rot. Incidence of stem rot and peanut yield were not affected (P≤0.05) by chloroacetamide herbicides in 1991, 1992, and 1993. Chlorimuron applied 60 d after emergence had no effect on stem rot incidence or peanut yield. Paired plots treated with thifluzamide had very low stem rot incidence and 27% greater peanut yields. Based on these studies, neither chloroacetamide herbicides nor chlorimuron predisposed peanut to stem rot.


Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 676-682 ◽  
Author(s):  
J. Augusto ◽  
T. B. Brenneman ◽  
A. K. Culbreath ◽  
P. Sumner

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


2007 ◽  
Vol 114 (3) ◽  
pp. 120-125
Author(s):  
A. S. Lithourgidis ◽  
D. G. Roupakias ◽  
K. Tzavella-Klonari

2011 ◽  
Vol 38 (2) ◽  
pp. 93-100 ◽  
Author(s):  
R. Scott Tubbs ◽  
John P. Beasley ◽  
Albert K. Culbreath ◽  
Robert C. Kemerait ◽  
Nathan B. Smith ◽  
...  

ABSTRACT Recent peanut cultivar releases are trending to a larger seed size, but have great resistance to tomato spotted wilt virus (TSWV). Larger-seeded cultivars cost more to plant than smaller at an equivalent population. Reduced seeding rates could save growers on seed costs and impede the spread of southern stem rot, but can reduce plant stands which can lower yields and increase TSWV incidence. Therefore, the objectives of this experiment were to compare seven peanut cultivars (Georgia Green, Georgia-06G, AT 3085RO, Florida-07, Tifguard, AP-3, and Georgia-03L) in single and twin row patterns at three seeding rates (17, 20, and 23 seed/m) on a sandy loam soil at Plains, GA for disease incidence, agronomic, and economic performance. Measured variables included yield and grade, plant height and stand, TSWV and southern stem rot incidence, and adjusted net revenue in 2008 and 2009. Twin rows outperformed single rows whenever differences occurred. The only factors consistently affected by reducing seeding rate were plant height and stand, both decreased at the lowest seeding rate. There was a trend toward lower yields (approximately 6% reduction) at the 17 seed/m rate in twin row pattern, although net returns were not diminished compared to the higher seeding rates since lower seed costs offset yield reductions. The cultivars Georgia-06G and Florida-07 had the highest yield and adjusted net revenue among the seven cultivars in both years. Tifguard and Georgia Green had lowest overall yields and would not be preferred cultivars in sandy loam soils. This study demonstrates that twin rows have higher yield, plant stands, and net revenue, plus reduced TSWV incidence than single row pattern, and a reduction in seeding rate to 17 seed/m can be made without serious risk of lost revenue. However, benefits of reducing seeding rate in twin rows were not as pronounced as they were for single rows, and exhibited a greater potential for lower yield. A grower planting in single rows would likely have the most to gain from planting fewer seed, especially under heavy southern stem rot pressure, but planting in twin rows would still be a preferred option over single rows.


1998 ◽  
Vol 25 (2) ◽  
pp. 59-62 ◽  
Author(s):  
W. J. Grichar

Abstract Field studies were conducted from 1987 to 1996 to evaluate the effects of long-term no-tillage, reduced-tillage, or full-tillage systems on peanut grade, yield, and stem rot (Sclerotium rolfsii) disease development. In 3 of 10 yr the full-tillage system outyielded the no-tillage system while the reduced tillage system resulted in yield increase over no-tillage systems in 2 yr. Reduced-tillage plots had a higher incidence of stem rot than full-or no-tillage in 4 of 10 yr. In 3 of 10 yr, peanut grade (% TSMK) was lower in no-tillage than full-tillage plots. The reduced tillage system has shown promise for use in Texas for peanut. However, no-tillage peanut systems have never produced yield and quality comparable to full-tillage systems.


2021 ◽  
Vol 21 (no 1) ◽  
Author(s):  
Sutha Raja Kumar ◽  
R. Arulselvi A ◽  
Rex Immanuel R ◽  
John Chrsitopher D. ◽  
Jaiganesh V. ◽  
...  

The present studies were undertaken to investigate the cultural, morphological and pathogenicity characters of Sclerotium rolfsii. Maximum per cent disease incidence was recorded in Nadiyappattu followed by Sivapuri, Kammapuram, Killai, Kurinjipadi, Parangipettai, Chathiram and Puthuchathiram in the decreasing order of merit of Cuddalore district, Tamil Nadu. The native isolates of S. rolfsii were isolated from the respective locations and designated as (SR1 to SR9). All the isolated showed variations with respect to colony character, mycelial growth, no of sclerotia, colour of sclerotia, shape and arrangement of sclerotia. Among the nine isolates of S. rolfsii collected from different groundnut growing areas of Cuddalore district, the isolate (SR5) collected from Nadiyappattu was found to be more virulent and recorded the maximum incidence followed by SR8 collected from Sivapuri. Maximum susceptibility was recorded when the plants are about 45 days showing disease incidence of upto 79.86 per cent.


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