Sarah H. Lancaster

Sicklepod (Senna obtusifolia) Control and Seed Production after 2,4-DB Applied Alone and with Fungicides or Insecticides'

Experiments were conducted during 1999, 2002, and 2003 to evaluate sicklepod control by 2,4-DB applied alone or in mixture with selected fungicides and insecticides registered for use in peanut. The fungicides boscalid, chlorothalonil, fluazinam, propiconazole plus trifloxystrobin, pyraclostrobin, or tebuconazole and the insecticides acephate, carbaryl, esfenvalerate, fenpropathrin, lambda-cyhalothrin, methomyl, or indoxacarb applied in mixtures with 2,4-DB did not reduce sicklepod control by 2,4-DB compared with 2,4-DB alone. The fungicide azoxystrobin reduced control in some but not all experiments. Sicklepod control was highest when 2,4-DB was applied before flowering regardless of fungicide treatment. Seed production and germination were reduced when 2,4-DB was applied 81 to 85 d after emergence when sicklepod was flowering. Applying 2,4-DB before flowering and at pod set and pod fill did not affect seed production. Nomenclature: Acephate, O,S-dimethyl acetylphosphoramidiothioate; azoxystrobin, methyl (E)-2-[2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl]-3-methoxyacrylate; boscalid, 3-pyridinecarboxamide,2-chloro-N-[4′-chloro(1,1′-biphenyl)-2-yl]; carbaryl, 1-napthyl N-methylcarbamate; chlorothalonil, tetrachloroisophthalonitrile; 2,4-DB; esfenvalerate, (S)-cyano (3-phenoxyphenyl) methyl (S)-4-chloro-α-(1-methylethyl)benzenacetate; fenpropathrin, α-cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcyclopropanecarboxylate; fluazinam, 3-chloro-N-[3-chloro-2,6-dinitro-4-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-2-pyridinamine; indoxacarb, (S)-methyl 7-chloro-2,5-dihydro2-[[ (methoxy-carbonyl) [ 4(trifluorometoxy)phenyl]amino]-carbonyl]indeno[1,2-e][1,3,4]oxadiazine-4a-(3H)-carboxylate; lambda-cyhalothrin, [1,α(S*),3α(Z)]-(±)-cyano-(3-phenoxyphenyl)methyl-3-(2-chloro-3,3,3-tifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate; methomyl, S-methyl-N-[(methylcarbamoyl)oxy] thioacetimidate; propiconazole, 1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl-methyl]-1H-1,2,4 triazole; pyraclostrobin, carbamic acid, [2-[[[1-(4-chlorophenyl)-1H-pyrazol-3yl]oxy]methyl]phenyl]methoxy-,methyl ester; tebuconazole, α-[2-(4-chlorophenyl)ethyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; trifloxystrobin, benzeneacetic acid, α-(methoxyimino)-2-[[[(E)-[1-[3-(trifluoromethyl)phenyl] ethylidene]amino]oxy]methyl]-, methylester (E,E); sicklepod, Senna obtusifolia L. Irwin and Barneby #3 CASOB; peanut, Arachis hypogaea L. Additional index word: Pesticide interaction. Abbreviation: DAE, days after emergence.

Influence of Selected Fungicides on Efficacy of Clethodim and Sethoxydim1

Field experiments were conducted to compare large crabgrass control by clethodim or sethoxydim applied alone and with selected fungicides registered for use in peanut. Fluazinam, propiconazole plus trifloxystrobin, or tebuconazole did not affect efficacy of clethodim or sethoxydim. Azoxystrobin, boscalid, chlorothalonil, and pyraclostrobin reduced efficacy of clethodim and sethoxydim in some experiments. Increasing the herbicide rate increased large crabgrass control regardless of the addition of chlorothalonil. In laboratory experiments, 14C absorption was less when 14C-clethodim or 14C-sethoxydim was applied with chlorothalonil. Pyraclostrobin and tebuconazole did not affect absorption of 14C-clethodim or 14C-sethoxydim. Nomenclature: Azoxystrobin, methyl (E)-2-[2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl]-3-methoxyacrylate; boscalid, 3-pyridinecarboxamide,2-chloro-N-[4′-chloro(1,1′-biphenyl)-2-yl]; chlorothalonil, tetrachloroisophthalonitrile; clethodim; fluazinam, 3-chloro-N-[3-chloro-2,6-dinitro-4-(trifluoromethyl)phenyl]-5-(trifluoromethyl)-2-pyridinamine; propiconazole, 1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl-methyl]-1H-1,2,4triazole; pyraclostrobin, carbamic acid,[2-[[[1-(4-chlorophenyl)-1H-pyrazol-3yl]oxy]methyl]phenyl]methoxy-,methyl ester; sethoxydim; tebuconazole, α-[2-(4-chlorophenyl)ethyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; trifloxystrobin, benzeneacetic acid, α-(methoxyimino)-2-[[[(E)-[1-[3-(trifluoromethyl)phenyl]ethylidene]amino]oxy]methyl]-,methylester (E,E); large crabgrass, Digitaria sanguinalis (L.) Scop. #3 DIGSA; peanut, Arachis hypogaea L. Additional index words: Herbicide absorption, pesticide interaction. Abbreviation: LSS, liquid scintillation spectrometry.

Interactions of Clethodim and Sethoxydim with Selected Agrichemicals Applied to Peanut

Experiments were conducted in North Carolina during 2002 and 2003 to evaluate broadleaf signalgrass and large crabgrass control by clethodim and sethoxydim applied in two-, three-, or four-way mixtures with fungicides, insecticides, and foliar fertilizer–plant growth regulator treatments. Broadleaf signalgrass and large crabgrass control by clethodim and sethoxydim was not reduced by the insecticides esfenvalerate, indoxacarb, or lambda-cyhalothrin. The fungicides azoxystrobin, chlorothalonil, pyraclostrobin, and tebuconazole reduced large crabgrass control by clethodim or sethoxydim in one or more of three experiments for each herbicide. Disodium octaborate and the plant growth regulator prohexadione calcium plus urea ammonium nitrate (UAN) mixed with clethodim and fungicides improved large crabgrass control in some experiments. In contrast, prohexadione calcium plus UAN and disodium octaborate did not affect broadleaf signalgrass or large crabgrass control by sethoxydim. Nomenclature: Azoxystrobin, methyl (E)-2-{2-[6-(2-cyanophenoxy) pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate; chlorothalonil, tetrachloroisophthalonitrile; clethodim; esfenvalerate, (S)-cyano (3-phenoxyphenyl) methyl (S)-4-chloro-α-(1-methylethyl)benzenacetate; indoxacarb, (S)-methyl 7-chloro-2,5-dihydro2-[[(methoxy-carbonyl)[4(trifluorometoxy)phenyl]amino]-carbonyl]indeno[1,2-e][1,3,4]oxadiazine-4a-(3H)-carboxylate; lambda-cyhalothrin, [1,α(S*),3α(Z)]-(±)-cyano-(3-phenoxyphenyl)methyl-3-(2-chloro-3,3,3-tifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate; prohexadione calcium, calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate; pyraclostrobin, methyl ester of [2-[[[1-(4-chlorophenyl)-1H-pyrazol-3yl]oxy]methyl]phenyl]methoxy-, carbamic acid; sethoxydim; tebuconazole, α-[2-(4-chlorophenyl)ethyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; broadleaf signalgrass, Brachiaria platyphylla (Griseb). Nash #3 BRAPP; large crabgrass, Digitaria sanguinalis (L.) Scop. # DIGSA. Additional index words: Pesticide compatibility, pesticide interaction. Abbreviations: PGR, plant growth regulator; UAN, urea ammonium nitrate.

Influence of Graminicide Formulation on Compatibility with Other Pesticides

Abstract Experiments were conducted from 2003 through 2006 to compare annual grass control by graminicides applied alone or with other pesticides and to determine whether graminicide formulation affected annual grass control and interactions with co-applied pesticides. Formulation and rate had no affect on broadleaf signalgrass or large crabgrass control by clethodim. The efficacy of clethodim in tank mixtures with acifluorfen plus bentazon, bentazon, chlorothalonil, imazapic, pyraclostrobin, or tebuconazole were not affected by clethodim formulation. Broadleaf signalgrass and large crabgrass control by clethodim was slightly reduced by acifluorfen plus bentazon, chlorothalonil, imazapic, and pyraclostrobin, but not by tebuconazole. Chlorothalonil and pyraclostrobin reduced broadleaf signalgrass control with quizalofop-P but did not reduce fall panicum control. Azoxystrobin, propiconazole, and tebuconazole did not affect efficacy of quizalofop-P. Nomenclature: Acifluorfen; azoxystrobin, methyl (E)-[2-[2-6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl]-3-methoxyacrylate; bentazon; chlorothalonil, tetrachloroisophthalonitrile; clethodim; imazapic; propiconazole, 1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl-methyl]-1H-1,2,4-triazol; pyraclostrobin, carbamic acid, [2-[[[1-(4-chlorophenyl)pyrazol-3-yl]oxymethyl]phenyl]methoxy-, methyl ester; quizalofop-P; sethoxydim; tebuconazole, α-[2-(4-chlorophenyl)ethyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; broadleaf signalgrass, Urochloa platyphylla (Nash) R.D. Webster UROPP; fall panicum, Panicum dichotomiflorum Michx. PANDI; large crabgrass, Digitaria sanguinalis (L.) Scop. DIGSA

Peanut (Arachis hypogaea L.) cultivar response to prohexadione calcium

Peanut digging efficiency is often reduced due to excessive vine growth. The plant growth regulator prohexadione calcium retards vegetative growth and improves row visibility by inhibiting internode elongation resulting in improved digging efficiency and in some instances increases in pod yield. The objective of this research was to determine the effects of prohexadione calcium on row visibility and pod yield of newly released and commercially available cultivars AT VC-2, Brantley, CHAMPS, Georgia Green, Gregory, Perry, Phillips, NC-V 11, NC 12C, Tamspan 90, and VA 98R and the breeding lines N02006, N01013T, and VT 976133. Although differences in row visibility were noted among cultivars, prohexadione calcium improved row visibility in almost every experiment regardless of cultivar. The cultivars NC 12C and Perry were more responsive to prohexadione calcium in terms of pod yield than NC-V 11 or VA 98R. Response of these cultivars was independent of digging date. In other experiments, prohexadione calcium improved row visibility of the cultivars AT VC-2, Gregory, NC-V 11, Perry, VA 98R, and Wilson, but did not increase yield when compared with non-treated peanut. In a final experiment, prohexadione calcium improved row visibility of the Virginia market type cultivars Brantley, CHAMPS, Gregory, and Phillips and the experimental lines N02006, N01013T, and VT 976133. Row visibility for the experimental line N01013T was improved at 2 of 4 sites by prohexadione calcium. In a final experiment, prohexadione calcium increased row visibility of Georgia Green, Gregory, and Tamspan 90 but did not affect pod yield of these cultivars.

Interactions of Late-Season Morningglory (Ipomoea spp.) Management Practices in Peanut (Arachis hypogaea) 1

Experiments were conducted in North Carolina during 2002 and 2003 to evaluate entireleaf morningglory control by 2,4-DB applied alone or with seven fungicides. In a separate group of experiments, tall morningglory control by 2,4-DB was evaluated when applied in four-way mixtures with the following: the fungicides azoxystrobin, chlorothalonil, pyraclostrobin, or tebuconazole; the insecticide lambda-cyhalothrin; and the foliar fertilizer disodium octaborate or the plant growth regulator (PGR) prohexadione calcium plus urea ammonium nitrate. Pyraclostrobin, but not azoxystrobin, boscalid, chlorothalonil, fluazinam, propiconazole plus trifloxystrobin, or tebuconazole, reduced entireleaf morningglory control by 2,4-DB. Mixtures of fungicides, insecticides, and foliar fertilizer/ PGR did not affect tall morningglory control by 2,4-DB. Placing artificial morningglory in the peanut canopy when fungicides were applied did not intercept enough fungicide to increase peanut defoliation by early leaf spot and web blotch or reduce pod yield compared with fungicide applied without artificial morningglory. Nomenclature: 2,4-DB; azoxystrobin; boscalid; chlorothalonil; fluazinam; lambda-cyhalothrin; prohexadione calcium; propiconazole; pyraclostrobin; tebuconazole; trifloxystrobin; entireleaf morningglory, Ipomoea hederacaea var integriuscula Gray #3 IPOHG; tall morningglory, Ipomoea purpurea (L.) Roth # PHBPU; early leaf spot, Cercospora arachidicola S. Hori; web blotch, Phoma arachidicola (Marsas et al.); peanut, Arachis hypogaea L. ‘NC-V 11’, ‘VA 98R’. Additional index words: Fungicide deposition, pesticide interactions, weed interference. Abbreviations: PGR, plant growth regulator; UAN, urea ammonium nitrate.

Weed Management in Peanut with Herbicide Combinations Containing Imazapic and Other Pesticides

Abstract Research was conducted in North Carolina to compare weed control by various rates of imazapic POST alone or following diclosulam PRE. In a second experiment, weed control by imazapic applied POST alone or with acifluoren, diclosulam, or 2,4-DB was compared. In a final experiment, yellow nutsedge control by imazapic alone and with the fungicides azoxystrobin, chlorothalonil, pyraclostrobin, and tebuconazole was compared. Large crabgrass was controlled more effectively by imazapic POST than diclosulam PRE. Common lambsquarters, common ragweed, and eclipta were controlled more effectively by diclosulam PRE than imazapic POST. Nodding spurge was controlled similarly by both herbicides. Few differences in control were noted when comparing imazapic rates after diclosulam PRE. Applying either diclosulam PRE or imazapic POST alone or in combination increased peanut yield over nontreated peanut in five of six experiments. Few differences in pod yield were noted when comparing imazapic rates. Acifluorfen, diclosulam, and 2,4-DB did not affect entireleaf morningglory, large crabgrass, nodding spurge, pitted morningglory, and yellow nutsedge control by imazapic. Eclipta control by coapplication of imazapic and diclosulam exceeded control by imazapic alone. The fungicides azoxystrobin, chlorothalonil, pyraclostrobin, and tebuconazole did not affect yellow nutsedge control by imazapic. Nomenclature: Acifluorfen; azoxystrobin, methyl (E)-2-{2-[6-(2-cyanophenoxy)pyrimidin-4-yloxy]phenyl}-3-methoxyacrylate; bentazon; chlorothalonil, tetrachloroisophthalonitrile; 2,4-DB; diclosulam; imazapic; pyraclostrobin, methyl [2-[[[1-(4-chlorophenyl)-1H-pyrazol-3-yl]oxy]methyl]phenyl]methoxycarbamate; tebuconazole, α-[2-(4-chlorophenyl)ethyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; common lambsquarters, Chenopodium album L. CHEAL; common ragweed, Ambrosia artemisiifolia L. AMBEL; eclipta, Eclipta prostrata L. ECLAL; entireleaf morningglory, Ipomoea hederacea var. integruscula Gray IPOHG; large crabgrass, Digitaria sanguinalis (L.) Scop. DIGSA; nodding spurge, Chamaesyce nutans (Lag.) Small EPHNU; pitted morningglory, Ipomoea lacunosa L. IPOLA; yellow nutsedge, Cyperus esculentus L. CYPES; peanut, Arachis hypogaea L

Weed and Peanut (Arachis Hypogaea) Response to Diclosulam Applied Post

Diclosulam is generally applied either PPI or PRE to peanut to control certain broadleaf weeds and suppress sedges. Research was conducted to determine efficacy and peanut response to POST applications of diclosulam at 9, 13, 18, and 27 g ai/ha. Efficacy of diclosulam was affected by application rate and environment. Common ragweed control ranged from 60 to 100%, entireleaf morningglory control from 56 to 100%, marestail control from 78 to 85%, and nodding spurge from 50 to 97%. Smooth pigweed and common lambsquarters were both controlled less than 35%. Diclosulam controlled yellow nutsedge and eclipta less than 70 and 80%, respectively. In separate experiments, diclosulam and imazapic controlled dogfennel more effectively than acifluorfen, bentazon, imazethapyr, lactofen, paraquat, or 2,4-DB. Visual estimates of peanut injury were 15% or less for all rates during both years. Peanut yield ranged from 3,340 to 3,730 kg/ha in 2002 and 5,230 to 5,820 kg/ha in 2003. Foliar injury and peanut pod yield were influenced by diclosulam rate, although no clear relation was evident. Cultivar and diclosulam rate did not interact with respect to visual injury or pod yield. Nomenclature: Acifluorfen, bentazon, diclosulam, imazapic, imazethapyr, lactofen, paraquat, 2,4-DB, common lambsquarters, Chenopodium album L. CHEAL, common ragweed, Ambrosia artemisiifolia L. AMBEL, dogfennel, Eupatorium capillifolium (Lam.) Small EUPCP, eclipta, Eclipta prostrata L. ECLAL, entireleaf morningglory, Ipomoea hederaceae var integriscula Gray IPOHG, marestail, Conyza canadensis (L.) Cronq. ERICA, nodding spurge, Chamaesyce nutans (Lag.) Small EPHNU, smooth pigweed, Amaranthus hybridus L. AMACH, yellow nutsedge, Cyperus esculentus L. #CYPES, peanut, Arachis hypogaea L. ‘NC-V 11’ ‘Perry’

Influence of Application Variables on Efficacy of Manganese-Containing Fertilizers Applied to Peanut (Arachis hypogaea L.)

Abstract Several formulations of the essential element boron (B) are commercially available for application to peanut (Arachis hypogaea L.) and other crops. Research was conducted in North Carolina...

Peanut (Arachis hypogaea L.) Response to the Harpin Protein Product Messenger

Abstract Experiments were conducted from 2002 through 2004 in North Carolina and during 2004 in Virginia to determine peanut response to harpin protein applied in the formulated product Messenger® ...