P. Dewayne Johnson

Peanut response to cultivar selection, digging date, and tillage intensity

reduced tillage systems often do not exceed those of conventional tillage. Determining the cause of inconsisPeanut (Arachis hypogaea L.) in the United States is generally tent yield response to reduced tillage would be benefigrown in conventionally tilled systems. However, interest in reduced tillage peanut production has increased. Five experiments were concial in determining when reduced tillage systems could ducted in North Carolina to determine if cultivar selection and digging be successfully implemented in peanut production. date affected peanut yield and economic value when peanut was Cultivar selection can have a dramatic effect on crop seeded into conventionally tilled seedbeds compared with strip tillage response to production and pest management practices. into small-grain cover crop or stubble from the crop planted the preCulpepper et al. (1997) reported that peanut cultivars vious summer. In separate experiments, peanut yield and economic responded differently to the plant growth regulator provalue in these tillage systems were compared with peanut strip-tilled hexadione calcium (calcium salt of 3,5-dioxo-4-propiointo beds prepared the previous fall (stale seedbeds). Cultivar selection nylcyclohexanecarboxylic acid). Cultivars also respond and digging date did not affect pod yield or gross value when compardifferently to digging date (Jordan et al., 1998). Disease ing tillage systems. Pod yield in conventional and stale seedbed sysmanagement approaches can be affected by cultivar setems was similar in all five experiments where these systems were compared, and yields in these tillage systems exceeded those of strip lection (Bailey, 2002). Virginia market-type cultivars vary tillage into crop stubble in three of five experiments. Pod yield was considerably in pod size, maturity, and several other agrosimilar among all three tillage systems in the other two experiments. nomic factors (Swann, 2002). Although not well estabIn experiments where only conventional tillage and strip tillage syslished in the literature, pod loss can be severe if peanut tems were compared, pod yield was similar between the two tillage is dug under poor soil conditions (Beam et al., 2002). systems in four experiments, higher in conventional tillage compared It is suspected that pod loss may be greater in reduced with strip tillage in one experiment, and higher for strip tillage comtillage systems than conventional tillage systems bepared with conventional tillage in one experiment. In 16 of 17 comcause the plants may be more difficult to dig. Peanut parisons, pod yield of peanut planted in conventional tillage systems cultivars with larger pods may be more susceptible to equaled or exceeded that of peanut planted into stubble from the digging losses compared with smaller-seeded cultivars previous crop. because they have a greater surface area, which may cause increased exposure to detachment during the digging process. Practitioners indicate that pod loss from P in the United States is typically grown in smaller-seeded runner market types is less than that for conventionally tilled systems (Sholar et al., 1995). large-seeded virginia market types during the digging Peanut response to reduced tillage has been inconsiscomponent of the harvest process. However, these comtent. Research suggests that yields in reduced tillage sysparisons have not been documented in the literature. tems can be lower than (Brandenburg et al., 1998; Cox Determining if pod yield differs among tillage systems and Sholar, 1995; Grichar, 1998; Jordan et al., 2001; for cultivars with different pod sizes may help explain Sholar et al., 1993; Wright and Porter, 1995) or similar inconsistent peanut response to reduced tillage systems. to (Baldwin and Hook, 1998; Dowler et al., 1999; HartStale seedbed crop production has been successful zog et al., 1998; Williams et al., 1998) yields in convenfor a variety of row crops, including soybean [Glycine tional tillage systems. Higher yields in reduced tillage max (L.) Merr.] and cotton (Gossypium hirsutum L.) systems have been associated with lower incidence of (Shaw, 1996). Seedbeds are prepared the previous fall tomato spotted wilt virus (TSWV) (Baldwin and Hook, or during the spring several weeks or months before 1998; Johnson et al., 2001; Wright et al., 2000). In most seeding directly into previously established stale seedexperiments where this disease is not a factor, yields in bed without significant soil disturbance. This approach to peanut production may be a viable alternative to both D.L. Jordan, P.D. Johnson, and A.S. Culpepper, Dep. of Crop Sci., conventional tillage systems and strip tillage directly Box 7620, North Carolina State Univ., Raleigh, NC 27695-7620; J.S. into stubble from the previous crop. Barnes, Peanut Belt Res. Stn., North Carolina Dep. of Agric. and The objectives of this research were to determine if Consumer Serv., Box 220, Lewiston-Woodville, NC 27849; C.R. Bogle, Dep. of Soil Sci., North Carolina State Univ., Upper Coastal Plain peanut response to tillage was associated with cultivar Res. Stn., Box 7619, Raleigh, NC 27695 and North Carolina Dep. of selection and digging date and if peanut yield in stale Agric. and Consumer Serv., Rt. 2 Box 400, Rocky Mount, NC 27801; seedbeds differs from yield in conventional tillage or R.L. Brandenburg, Dep. of Entomol., Box 7613, North Carolina State strip tillage into crop stubble. Univ., Raleigh, NC 27695-7613; and J.E. Bailey, Dep. of Plant Pathol., Box 7616, North Carolina State Univ., Raleigh, NC 27695-7616. ReAbbreviations: CBR, Cylindrocladium black rot; %ELK, percentage ceived 11 Apr. 2002. *Corresponding author (david_jordan@ncsu.edu). of extra large kernels; %TSMK, percentage of total sound mature kernels; TSWV, tomato spotted wilt virus. Published in Agron. J. 95:380–385 (2003).

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.

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

Compatibility of In-Furrow Application of Acephate, Inoculant, and Tebuconazole in Peanut (Arachis hypogaea L.)

Abstract Research was conducted in North Carolina to compare tobacco thrips (Frankliniella fusca Hinds) control, early season peanut emergence and growth, and pod yield with combinations of the insecticide acephate, inoculant containing Brady rhizobium, and the fungicide tebuconazole applied in the seed furrow during planting. Although interactions among treatment factors were significant, greater control of tobacco thrips damage was noted when acephate was applied and in some cases when tebucanozole was applied. Tebucanzole-treated peanut emerged more slowly than peanut not receiving tebucanazole. Delayed emergence of tebuconazole-treated peanut most likely resulted in emergence when fewer tobacco thrips were present in fields. Peanut pod yield was affected by acephate, inoculant, and tebuconazole independently. Applying acephate and inoulcant increased pod yield in two and three of five experiments, respectively. Pod yield was lower in one of five experiments when tebuconazole was applied. These data su...

Response of Virginia market type peanut to interactions of cultivar, calcium, and potassium.

Peanut kernel size can influence response to calcium. While runner market type peanut cultivars often do not require supplemental calcium at flowering, application of gypsum (CaSO ) is routinely recommended for large-seeded Virginia market type peanut cultivars. However, kernel size varies considerably for Virginia market type peanut. Research was conducted from 2001-2005 at two locations in North Carolina to determine if the gypsum rate with or without prior potassium application should vary for the Virginia market type peanut cultivars NC-V 11 (625 kernels/lb seed) and Gregory (450 kernels/lb seed). Although the percentage of total sound mature kernels (%TSMK) was not affected by the interaction of cultivar and gypsum rate, pod yield and the percentage of extra large kernels (% ELK) was affected by this interaction. The interaction of location, year, and gypsum rate was significant for pod yield, %TSMK, and %ELK. Potassium had no major effect on pod yield or market grade characteristics. Seed germination and percentages of calcium deficient kernels were not affected by the interaction of cultivar and gypsum rate but was affected by the main effect of these treatment factors. These data suggest that although differences in peanut response to Virginia market type peanut exist, increasing the rate of gypsum above the rate currently recommended is not necessary for large-seeded Virginia market type peanut. Introduction The need for adequate calcium in the pegging zone of soil for kernel development is well documented for peanut (2,3,7,8,9,19). A strong relationship between pod yield and soil calcium concentration exists for small-seeded runner market type peanut, but the relationship is relatively poor for large-seeded Virginia market type peanut (7,8). Cooperative Extension recommendations in several states in the United States include soil testing as a tool for determining the need for supplemental gypsum application at flowering for runner market type cultivars (1,6,10,11,13). Because of the poor relationship between soil calcium concentration and pod yield for Virginia market type peanut, supplemental calcium is generally recommended for all large-seeded Virginia market types (1,6,10,11,13). However, Virginia market type peanut vary considerably in size of kernels and pods, and in recent years some growers have applied rates of gypsum higher than the standard recommendation for largeseeded cultivars (13). Research is needed to determine if gypsum rates need to be adjusted for Virginia market type peanut based on kernel and pod size. The concentration of potassium in soil can influence calcium absorption by developing kernels and pods (7,8), and recommendations on gypsum application to runner market types include determining the ratio of calcium to potassium in the pegging zone (11,13). Elevated concentrations of potassium in the pegging zone could interact with gypsum rate and cultivar kernel size. In a 4 26 February 2010 Crop Management survey of growers in North Carolina with Virginia market type peanut with pod yields typically higher the state average, approximately 80% of growers applied some form of N-P O -K O in the spring prior to planting (17). In this same group of growers, 98% applied gypsum at flowering (17). The relationship of calcium and potassium fertility has not been evaluated with more recently released Virginia market type peanut cultivars with varying kernel size. The cultivars Gregory and NC-V 11 offer the widest range of kernel and pod size of Virginia market type peanut grown commercially (13). These cultivars have similar disease reaction, and pod maturity of these cultivars progresses in a similar manner (13,20). Research was conducted to define interactions among the cultivars Gregory and NC-V 11, gypsum rate, and potassium to determine if the gypsum rate needs to be modified based on kernel and pod size of Virginia market type peanut. Locations, Soil Series, Tillage, and Pest Management The experiment was conducted in North Carolina from 2001-2005 at the Peanut Belt Research Station located near Lewiston-Woodville and the Upper Coastal Plain Research Station located near Rocky Mount. Soil at LewistonWoodville was a Norfolk sandy loam (fine-loamy, siliceous, thermic, Typic Paleudults). Soil at Rocky Mount was a Goldsboro loamy sand (fine-loamy, siliceous, thermic Aquic Paleudults). Peanut was planted in conventionallyprepared raised seedbeds in plots 2 rows wide (36-inch spacing) by 30 ft in length. Production and pest management practices were based on Cooperative Extension recommendations for the region (5,13,14,20). Cultivar, Gypsum, and Potassium Treatments Treatments consisted of a factorial arrangement of two levels of cultivar (Gregory and NC-V 11), three levels of gypsum (no gypsum, the recommended use rate of gypsum, and 1.5 times the recommended use rate of gypsum), and two levels of potassium fertilizer applied immediately after planting to the soil surface [no potassium and 250 lbs/acre 0-0-60 (N, P O -K O)]. The seeding rate for Gregory (12) (450 seeds/lb) was 150 lbs/acre (13). The seeding rate for NC-V 11 (22) (625 seeds/lb) was 115 lbs/acre (13). Cultivars were seeded at a rate designed to achieve an in-row plant population of 4 to 5 plants/ft. The broadcast standard rate of gypsum during 2001-2004 was 1250 lbs/acre (USG 500, 70% calcium sulfate) (13). Gypsum at 600 lb/acre (USG Ben Franklin, 85% calcium sulfate) (13) was banded in 2005 (18-inch band on rows spaced 36 inches apart). Rates are based on treated area. Gypsum was applied in late June of each year at early flower production. Immediately prior to application of gypsum, twelve soil cores to a depth of three inches were collected from no potassium and potassium-treated plots for the cultivar Gregory. Soil pH, soil potassium, and soil calcium levels for these samples are presented in Table 1. Peanut was dug and vines were inverted in late September or early October based on pod mesocarp color (21). Pods and vines were allowed to air-dry for 4 to 7 days prior to threshing, and final pod yield was adjusted to 8% moisture. Percentage of extra large kernels (%ELK) and total sound mature kernels (% TSMK) were determined from a one pound sample of pods collected at harvest. One hundred kernels from the sound mature kernel fraction of each sample during 2001, 2004, and 2005 were used to determine the percentage of kernels showing a calcium deficiency and standard germination (4). 2 5 2

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 Bradyrhizobia Inoculant Applied In-furrow with Agrichemicals

Abstract Bradyrhizobia is often applied in the seed furrow when peanut is planted to ensure nodulation and subsequent biological nitrogen fixation (BNF). Several fungicides, insecticides, and fertilizer solutions are registered for in-furrow application in peanut while others or currently being evaluated for possible use. The effect of these products on efficacy of Bradyrhizobia inoculant has not been thoroughly investigated. Research was conducted in North Carolina and Virginia to determine peanut response to in-furrow application of Bradyrhizobia inoculant alone or with the fungicides azoxystrobin, boscalid, pyraclostrobin, propiconazole plus trifloxystrobin, and tebuconazole; the insecticide imidacloprid; and the commercial fertilizer Asset® RTU. Peanut yield did not differ in three experiments during 2002 when inoculant was applied alone or with the fungicides azoxystrobin, boscalid, pyraclostrobin, propiconazole plus trifloxystrobin, or tebuconazole. In experiments from 2004–2007, pod yield was lower...

Comparison of cropping systems including corn, peanut, and tobacco in the North Carolina Coastal Plain.

Research was conducted in North Carolina from 2001 to 2006 to determine disease development, parasitic nematode population in soil, crop yield, and cumulative economic return in rotation systems including corn, peanut, and tobacco. Specific rotations included two consecutive cycles of corn-corn-peanut, corn-tobacco-peanut, or tobacco-corn-peanut; five years of corn followed by peanut, and corn-corn-tobacco-corn-corn-peanut. In the final year of the experiment when only peanut was planted, the Cylindrocladium black rot (caused by Cylindrocladium parasiticum) (CBR)-susceptible cultivar Gregory and the CBRresistant cultivar Perry were included. Increasing the number of years between peanut plantings increased yield of peanut in the final year of the experiment when Gregory was planted but not when Perry was planted. Incidence of CBR was highest when peanut was planted twice during the duration of the experiment compared with only once. No difference in ring nematode was observed regardless of rotation in the final year of the experiment. The highest soil population of stunt nematode was noted when five years of corn was followed by peanut with the lowest soil population of this nematode noted following two cycles of tobacco-corn-peanut. Cropping systems that included tobacco provided higher cumulative economic returns regardless of rotation sequence in most instances.