scholarly journals Night Spraying Peanut Fungicides II. Application Timings and Spray Deposition in the Lower Canopy

Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 683-689 ◽  
Author(s):  
J. Augusto ◽  
T. B. Brenneman ◽  
A. K. Culbreath ◽  
P. Sumner
Keyword(s):  
Arachis Hypogaea ◽  
Chemical Control ◽  
Spray Deposition ◽  
Sclerotium Rolfsii ◽  
Early Morning ◽  
Stem Rot ◽  
Plant Tissues ◽  
Spray Penetration ◽  
Systemic Fungicides ◽  
Coverage Density

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.

scholarly journals Assessing Systemicity of Peanut Fungicides Through Bioassay of Plant Tissues with Sclerotium rolfsii

Plant Disease ◽  
2012 ◽  
Vol 96 (3) ◽  
pp. 330-337 ◽  
Author(s):  
J. Augusto ◽  
T. B. Brenneman
Keyword(s):  
Arachis Hypogaea ◽  
Field Experiments ◽  
Sclerotium Rolfsii ◽  
Plant Tissues ◽  
Systemic Fungicides ◽  
Lateral Branches ◽  
Primary Lateral

To better understand movement of systemic fungicides in peanut (Arachis hypogaea), three terminal, fully expanded leaves of primary lateral branches of ‘Tifrunner’ peanut were treated with prothioconazole + tebuconazole (Provost, 0.29 kg a.i./ha), azoxystrobin (Abound, 0.31 kg a.i./ha), or flutolanil (Moncut, 0.79 kg a.i./ha) in field experiments. Basipetal leaves and pods on the same branch with the treated leaves were sequentially numbered from 1 to 3, with 1 being closest to treated foliage. These nontreated tissues, with newly formed terminal leaves, were sampled 4, 8, and 12 days after treatment for bioassay with Sclerotium rolfsii. All fungicides protected new acropetal leaves while prothioconazole + tebuconazole also provided some inhibition of S. rolfsii in nontreated basipetal leaves but no fungicide protected pods. In the greenhouse, applications of prothioconazole + tebuconazole or prothioconazole (Proline, 0.18 kg a.i./ha) to main stems of ‘Georgia Green’ provided some protection to leaves from nontreated cotyledonary branches sampled 14 days after last treatment but S. rolfsii was not inhibited on nontreated roots, stems, or pods. The results demonstrate acropetal protection by all fungicides evaluated, and indicate that prothioconazole + tebuconazole or prothioconazole applied to foliage can sometimes reduce diseases in the lower, nontreated portions of the plant.

Potential for Improved Control of Southern Stem Rot of Peanut with Resistance and Fungicides1

1985 ◽  
Vol 12 (1) ◽  
pp. 4-7 ◽  
Author(s):  
B. B. Shew ◽  
M. K. Beute ◽  
J. E. Bailey
Keyword(s):  
North Carolina ◽  
Disease Resistance ◽  
Arachis Hypogaea ◽  
Sclerotium Rolfsii ◽  
Stem Rot ◽  
Arachis Hypogaea L ◽  
Disease Loci ◽  
Moderate Resistance

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.

Partial resistance of Southern Runner, Arachis hypogaea, to stem rot caused by Sclerotium rolfsii1

1990 ◽  
Vol 17 (2) ◽  
pp. 65-67 ◽  
Author(s):  
T. B. Brenneman ◽  
W. D. Branch ◽  
A. S. Csinos
Keyword(s):  
Arachis Hypogaea ◽  
Disease Incidence ◽  
Sclerotium Rolfsii ◽  
Field Tests ◽  
Stem Rot ◽  
Pod Yield ◽  
Industry Standard ◽  
Arachis Hypogaea L ◽  
The Mean ◽  
Disease Loci

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.

scholarly journals Reaction of Select Peanut (Arachis hypogaea L.) Lines to Southern Stem Rot and Pythium Pod Rot Under Varied Disease Pressure

1989 ◽  
Vol 16 (1) ◽  
pp. 9-14 ◽  
Author(s):  
O. D. Smith ◽  
T. E. Boswell ◽  
W. J. Grichar ◽  
C. E. Simpson
Keyword(s):  
Arachis Hypogaea ◽  
Disease Incidence ◽  
Sclerotium Rolfsii ◽  
Stem Rot ◽  
Resistant Parent ◽  
Breeding Lines ◽  
Arachis Hypogaea L ◽  
Significant Yield ◽  
Considerable Resistance ◽  
Disease Pressure

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.

Chloroacetamide Herbicides and Chlorimuron Do Not Predispose Peanut (Arachis hypogaea) to Stem Rot (Sclerotium rolfsii)1

1994 ◽  
Vol 21 (2) ◽  
pp. 126-129 ◽  
Author(s):  
W. Carroll Johnson ◽  
Timothy B. Brenneman ◽  
Benjamin G. Mullinix
Keyword(s):  
Arachis Hypogaea ◽  
Sclerotium Rolfsii ◽  
Field Studies ◽  
Stem Rot ◽  
Experimental Site ◽  
High Incidence ◽  
History Of

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.

scholarly journals Night Spraying Peanut Fungicides I. Extended Fungicide Residual and Integrated Disease Management

Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 676-682 ◽  
Author(s):  
J. Augusto ◽  
T. B. Brenneman ◽  
A. K. Culbreath ◽  
P. Sumner
Keyword(s):  
Disease Management ◽  
Chemical Control ◽  
Sclerotium Rolfsii ◽  
Residual Activity ◽  
Field Trials ◽  
Stem Rot ◽  
Integrated Disease Management ◽  
Cercospora Arachidicola ◽  
Puccinia Arachidis ◽  
Fungicide Efficacy

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.

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