Management of stem rot of peanuts (Arachis hypogaea) caused by Sclerotium rolfsii with fungicides

1995 ◽  
Vol 14 (2) ◽  
pp. 111-115 ◽  
Author(s):  
W.J. Grichar
1985 ◽  
Vol 12 (1) ◽  
pp. 4-7 ◽  
Author(s):  
B. B. Shew ◽  
M. K. Beute ◽  
J. E. Bailey

Abstract Potential for improved control of southern stem rot caused by Sclerotium rolfsii Sacc.on peanut (Arachis hypogaea L.) was evaluated by combining moderate resistance with fungicide use. Various fungicides including carboxin, oxycarboxin, propiconazol, OAC 3890, and PCNB were applied to peanut lines NC 8C, NC Ac 18016, and Florigiant in North Carolina during 1980, 1981, and 1982. Consistently fewer disease loci occurred on NC Ac 18016 than on NC 8C or Florigiant. At least one fungicide reduced stem rot incidence in two of three years tested, but fungicide use did not result in greater yields. Effects of disease resistance and fungicides on suppression of stem rot development were additive.


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.


Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 683-689 ◽  
Author(s):  
J. Augusto ◽  
T. B. Brenneman ◽  
A. K. Culbreath ◽  
P. Sumner

Chemical control of soilborne peanut (Arachis hypogaea) diseases requires deposition of fungicide on plant tissues near the soil. Four applications of a protectant fungicide, chlorothalonil (1.26 kg a.i./ha), or a systemic, azoxystrobin (0.21 kg a.i./ha), pyraclostrobin (0.21 kg a.i./ha), or prothioconazole (0.08 kg a.i./ha) plus tebuconazole (0.15 kg a.i./ha), were sprayed either (i) early in the morning (3:00 to 5:00 A.M., with folded and wet leaves), (ii) during daylight (10:00 A.M. to 12:00 P.M., with unfolded and dry leaves), or (iii) in the evening (9:00 to 10:00 P.M., with folded and dry leaves). All timings of systemic fungicides provided similar control of foliar diseases. Early-morning applications of pyraclostrobin and prothioconazole plus tebuconazole decreased stem rot (caused by Sclerotium rolfsii) at digging compared with day and evening applications. All systemic fungicides increased yield when applied at early-morning compared with day applications. Spray coverage, density, and droplet size were higher with night than day applications, and differences were more evident in the lower canopy layers. These results suggest that applications made early in the morning to folded, wet leaves can improve spray penetration of peanut canopies, thus improving stem rot control and increasing yield.


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.


2010 ◽  
Vol 11 (1) ◽  
pp. 27 ◽  
Author(s):  
Joao Augusto ◽  
Timothy B. Brenneman ◽  
Alexander S. Csinos

Peanut (Arachis hypogaea L.) is monocultured in western Nicaragua on loamysand soils, and a pod rot of unknown etiology can greatly reduce crop yield. Pythium myriotylum was frequently isolated from symptomatic pods in fields surveyed at Cosiguina, Leon, and Chinandega regions, although Rhizoctonia and Fusarium were also common. Applications of mefenoxam (0.57 kg a.i./ha), azoxystrobin (0.34 kg a.i./ha), and gypsum (670 kg/ha) at beginning pod and 28 to 35 days later were evaluated in field trials to determine their effects on pod rot and yield. Mefenoxam consistently decreased pod rot incidence and increased yield when disease was severe at Cosiguina. In Leon and Chinandega, azoxystrobin increased yield in fields with little pod rot, apparently by controlling stem rot (Sclerotium rolfsii), but did not decrease pod rot incidence. Application of gypsum had no effect on pod rot incidence or yield, but sometimes increased calcium levels in shells. Pod mycoflora isolations and response to mefenoxam suggest P. myriotylum is the primary cause of peanut pod rot in Nicaragua, especially in Cosiguina, where pod rot incidence was high. Accepted for publication 4 November 2009. Published 15 February 2010.


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