Effects of Applied Plant Nutrients on Sclerotinia Blight Incidence in Peanuts1

1981 ◽  
Vol 8 (1) ◽  
pp. 48-52 ◽  
Author(s):  
D. L. Hallock ◽  
D. M. Porter

Abstract Field experiments were conducted in Southampton County, Virginia in 1978 and 1979 on Altavista loamy fine sand (Aquic Hapludult) to determine whether applied nutrients affect the severity of Sclerotinia blight in peanuts (Arachis hypogaea L.) caused by Sclerotinia minor. Soil or foliar applications of N, K, Ca, Mg, P, Mn, Zn, Fe, B, S, and Cl were evaluated alone and/or in various combinations and formulations. Multiple Zn or Cu sprays applied on the foliage suppressed Sclerotinia blight symptoms most during fruit development. Yields in plots sprayed with four 1.12-kg/ha applications of Zn were 1,965 kg/ha greater than in untreated plots in 1978. Four 2.24 kg/ha sprays of Zn increased yields 810 kg/ha in 1979. In 1978, CuSO4 sprayed in a manner similar to ZnSO4 was the second most effective treatment among the simple nutrient materials. Zinc and Cu (sulfates) applied in a multi-nutrient commercial material which also contains Mn, Ca, and P suppressed Sclerotinia blight symptoms nearly as effectively as ZnSO4 sprays. Soil applied Zn or Cu (sulfates) at rates of 22.4 and 11.2 kg/ha, respectively, were relatively ineffective. Sequestrene Cu applied in four 0.56 kg/ha sprays of Cu suppressed Sclerotinia blight as effectively as four 2.24 kg/ha Zn sprays in 1979. Also, Sequestrene Zn and THIS Cu applied similarly to Sequestrene Cu decreased the disease symptoms in 1979.

1989 ◽  
Vol 16 (2) ◽  
pp. 113-115 ◽  
Author(s):  
D. M. Porter ◽  
R. A. Taber ◽  
D. H. Smith

Abstract The incidence of Sclerotinia minor was assessed in seed of two peanut (Arachis hypogaea L.) varieties (VA 81B and Florigiant) harvested from two fields in Virginia exhibiting disease symptoms typical of Sclerotinia blight. The incidence of S. minor in peanut seed with pink, light brown and dark brown testae riding a 6.4 × 25.4 mm screen averaged 1.5, 3.9 and 6.0%, respectively, from both fields. Similar trends were evident with colonization of seed by other fungi. The incidence of S. minor from pieces of testa removed from seed from both fields averaged 3.4% and 2.6%, respectively. However, the incidence of S. minor from seed cotyledons with testae removed was extremely low (<0.1%). Sclerotia of S. minor were not observed on, in or under the testa of seed or between the cotyledons of seed in prepared seed lots (lots containing only seed with pink and light brown testae). BOTEC, a seed treatment fungicide applied at recommended rate (2.5 g/kg), reduced the incidence of S. minor in peanut seed from 4.5% to 0.1%. Similar decreases were noted in other seedbome fungi commonly associated with peanut seed.


1995 ◽  
Vol 22 (2) ◽  
pp. 114-120 ◽  
Author(s):  
J. V. Altom ◽  
R. B. Westerman ◽  
D. S. Murray

Abstract Field experiments were conducted from 1991 to 1993 to evaluate eclipta, Eclipta prostrata L., control and peanut, Arachis hypogaea L., response to herbicide treatments. Fomesafen {5-[2-chloro-4-(trifluoro-methyl)phenoxy]-N-(methylsulfonyl)-2-nitrobenzamide} applied at cracking was the only preemergence-applied herbicide which provided season-long control (>84%). Herbicides applied postemergence were more effective when the eclipta was less than 5 cm in height. The most consistent early postemergence treatments were bromoxynil (3,5-dibromo-4-hydroxybenzonitrile), bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazm-4(3H)-one 2,2-dioxide], and bentazon + acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid} + 2,4-DB [4-(2,4-dichloro-phenoxy)butanoic acid]. Various other early postemergence followed by late postemergence sequential treatments also were equally effective. Minor peanut injury was observed at the early season rating from several herbicides; however, all injury had disappeared by the late season rating. Eclipta control did not consistently improve peanut pod yield.


2012 ◽  
Vol 39 (1) ◽  
pp. 9-14 ◽  
Author(s):  
P. A. Dotray ◽  
W. J. Grichar ◽  
T. A. Baughman ◽  
E. P. Prostko ◽  
T. L. Grey ◽  
...  

Abstract Field experiments were conducted at nine locations in Texas and Georgia in 2005 and 2006 to evaluate peanut tolerance to lactofen. Lactofen at 220 g ai/ha plus crop oil concentrate was applied to peanut at 6 leaf (lf), 6 lf followed by (fb) 15 days after the initial treatment (DAIT), 15 DAIT alone, 6 lf fb 30 DAIT, 30 DAIT alone, 6 lf fb 45 DAIT, 45 DAIT alone, 6 lf fb 60 DAIT, and 60 DAIT alone in weed-free plots. Lactofen caused visible leaf bronzing at all locations. Yield loss was observed when applications were made 45 DAIT, a timing that would correspond to plants in the R5 (beginning seed) to R6 (full seed) stage of growth. At all locations except the Texas High Plains, this application timing was within the 90 d preharvest interval. Growers who apply lactofen early in the peanut growing season to small weeds should have confidence that yields will not be negatively impacted despite dramatic above-ground injury symptoms; however, applications made later in the season, during seed fill, may adversely affect yield.


1981 ◽  
Vol 8 (1) ◽  
pp. 66-73 ◽  
Author(s):  
G. A. Buchanan ◽  
E. W. Hauser ◽  
R. M. Patterson

Abstract Experiments were conducted from 1975 to 1977 to determine the efficacy of herbicides for control of bur gherkin (Cucumis anguria L.) in peanuts (Arachis hypogaea L.). Most bur gherkins seed planted in the field germinated in the upper 2.5 cm of soil, although some seed germinated from 7 cm. In greenhouse and field experiments, preplant-incorporated applications of vernolate (S-propyl dipropylthiocarbamate) substantially reduced the green weight of bur gherkin plants and also improved the efficacy of several cracking and postemergence herbicidal treatments. Postemergence treatment sequences were much more effective when they were begun while bur gherkins were in the cotyledonary stage of development rather than the 3- to 5-leaf stage. Preplanting application and incorporation of vernolate + benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine), followed by a cracking application of alachlor [2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide] + naptalam (N-1-naphthylphthalamic acid) + dinoseb (2-sec-butyl-4,6-dinitrophenol), followed by dinoseb controlled bur gherkins. Some of the most intensive herbicide programs reduced the yield of peanuts in some experiments. Bur gherkin plants that survived the herbicide treatments produced substantial quantities of fruit and seed.


2006 ◽  
Vol 7 (1) ◽  
pp. 19 ◽  
Author(s):  
Jason E. Woodward ◽  
Timothy B. Brenneman ◽  
Robert C. Kemerait ◽  
Albert K. Culbreath ◽  
James R. Clark

Sclerotinia blight (Sclerotinia sclerotiorum (Lib.) de Bary) was recently identified in a commercial peanut (Arachis hypogaea L.) field in Appling County, GA. Symptoms were first observed on the cultivars Tifrunner and Georgia 02C. Plant inoculations and a detached leaflet assay were conducted to determine the susceptibility of the cultivars Georgia Green, Georgia 02C, Georgia 03L, AP-3, Georgia 01R, Hull, C-99R, and Tifrunner. For plant inoculations, lesion lengths were greatest for Okrun, the susceptible control, and Georgia 02C; lesion lengths for C-99R and Georgia 01R did not differ significantly from Tamspan 90, the resistant control. Georgia Green, the current commercial standard, exhibited intermediate lesion lengths. Similar results were obtained from the detached leaflet assay. These results suggest that differing levels of resistance to S. sclerotiorum are available in runner cultivars used in the southeastern United States. Accepted for publication 27 March 2006. Published 31 May 2006.


2000 ◽  
Vol 27 (1) ◽  
pp. 11-16 ◽  
Author(s):  
G. Wehtje ◽  
B. J. Brecke ◽  
N. R. Martin

Abstract Field experiments were conducted over two growing seasons (1995 and 1996) and at two locations (Jay, FL, and Headland, AL) to identify the most effective herbicide program for Florida beggarweed [Desmodium tortuosum (SW) D.C.] control in peanut (Arachis hypogaea L.). The most common herbicides used for Florida beggarweed control—including preemergence (PRE), early-postemergence (EPOST), mid-postemergence (MPOST) and late-postemergence (LPOST) applied treatments—were evaluated in a factorial treatment arrangement. All treatments had merit and could be assembled into programs that resulted in maximum weed control, crop yield, and net returns. However, at least two of the four treatment timings were required to reach this level. Four systems were consistently associated with the maximum statistical grouping for both yield and net returns, as well as acceptable Florida beggarweed control (> 81%). These systems were (a) paraquat + bentazon applied EPOST, followed by pyridate + 2,4-DB MPOST; (b) same as (a) only preceded by norflurazon applied PRE; (c) imazapic applied EPOST followed by pyridate + 2,4-DB MPOST; and (d) norflurazon applied PRE, followed by imazapic EPOST.


1996 ◽  
Vol 23 (1) ◽  
pp. 30-36 ◽  
Author(s):  
W. James Grichar ◽  
A. Edwin Colburn

Abstract Field experiments were conducted in 1991 and 1993 to evaluate flumioxazin alone and in various herbicide programs for weed control in peanut. Flumioxazin alone provided inconsistent control of annual grasses, while the addition of pendimethalin or trifluralin improved control considerably. Pitted morningglory (Ipomoea lacunosa L.) and ivyleaf morningglory [Ipomoea hederacea (L.) Jacq.] control was > 75% when flumioxazin was used alone. Flumioxazin caused early season peanut stunting with some recovery within 4 to 6 wk. Postemergence applications of imazethapyr or lactofen increased peanut stunting.


1985 ◽  
Vol 12 (1) ◽  
pp. 41-45 ◽  
Author(s):  
D. M. Porter ◽  
P. M. Phipps

Abstract Procymidone-tolerant isolates of Sclerotinia minor Jagger were cross-tolerant to iprodione, vinclozolin and dicloran. Hyphal growth of procymidone-tolerant isolates an agar amended with 1 to 100 μg/mL procymidone, iprodione, vinclozolin or dicloran was similar. Procymidone-tolerant isolates were tolerant to all fungicides after 10 weekly hyphal tip transfers to nonamended agar. Subsequently, cross-tolerance persisted on agar amended with either 10 μg/mL procymidone, iprodione, vinclozolin or dicloran. Most procymidone-tolerant isolates of S. minor were pathogenic to peanuts (Arachis hypogaea L.) and caused symptoms similar to those initiated by sensitive isolates.


1984 ◽  
Vol 11 (2) ◽  
pp. 60-63 ◽  
Author(s):  
M. E. Walker ◽  
W. D. Branch ◽  
T. P. Gaines ◽  
B. G. Mullinix

Abstract Field experiments were conducted on Lakeland sand (Thermic, coated Typic Quartz-ipsaments) during 1981-82 to determine the effect of foliarly applied N on yield, grade, and N, P, K, Ca, and Mg concentration of leaves and seed of nodulating and non-nodulating peanut (Arachis hypogaea L.). Nodulating cultivars; Florunner, Early Bunch, and Tifrun, and three non-nodulating experimental lines were sprayed 0, 1, 2 or 4 times at 13.5 kg N/ha beginning 28 days after emergence. Foliar application of N increased the yield of Florunner, Tifrun, and all non-nodulating lines, but had no effect on Early Bunch. The addition of N to non-nodulating peanut increased the percent fancy pods, extra large kernels, and weight of seed. Seed N concentration of non-nodulating lines increased with higher rates of N, but was higher in the nodulating cultivars. Seed of non-nodulating lines contained higher levels of P, K, and Mg than seed of nodulating lines. Nodulating lines had higher concentration of leaf N than did non-nodulating lines. The leaves of the non-nodulating lines contained higher levels of P, Ca, and Mg than those of the nodulating cultivars; whereas levels of K were higher for nodulating lines.


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