VA-C 92R Research Articles

Virginia Market-Type Peanut (Arachis hypogaea) Cultivar Tolerance and Yield Response to Flumioxazin Preemergence1

Field studies were conducted in 1996 and 1997 to evaluate response of eight peanut cultivars to flumioxazin applied preemergence (PRE) at 71 g ai/ha. Peanut cultivars evaluated include ‘NC 12C’, ‘NC 7’, ‘VAC 92R’, ‘NC-V 11’, ‘NC 10C’, ‘AT VC 1’, ‘NC 9’, and the experimental breeding line ‘N9001OE’. Visible injury 3 wk after planting in 1996 was 3% or less regardless of cultivar. In 1997, all cultivars were injured 15 to 28% with flumioxazin PRE, except VC 1, which was injured 45%. No visible injury was observed at 5 and 9 wk after planting. Flumioxazin did not influence the incidence of early leaf spot, late leaf spot, southern stem rot, cylindrocladium black rot, or tomato spotted wilt virus. Flumioxazin did not affect percentage of extra-large kernels, sound mature kernels, other kernels, and total yield.Nomenclature: Flumioxazin; peanut, Arachis hypogaea L., ‘NC 12C’, ‘NC 7’, ‘VAC 92R’, ‘NC-V 11’, ‘NC 10C’, ‘AT VC 1’, ‘NC 9’, ‘N9001OE’.Additional index words: Disease interaction, Cylindrocladium crotalariae (Loos) Bell and Sobers, Cercospora arachidicola Hori, Cercosporidium personatum (Berk. and Curt.), Sclerotium rolfsii Sacc., grade parameters, extra-large kernels, sound mature kernels, sound splits, total kernels, other kernels, fancy pods.Abbreviations: CBR, cylindrocladium black rot; DAP, days after planting; ELK, extra-large kernels; PPI, preplant incorporated; PRE, preemergence; SMK, sound mature kernels; SS, sound splits; TMSK, total sound mature kernels; TSWV, tomato spotted wilt virus; WAP, weeks after planting.

Diclosulam Does Not Influence Yields in Eight Virginia Market-Type Peanut (Arachis hypogaea) Cultivars1

Abstract: Field studies were conducted in 1996 and 1997 to evaluate response of eight peanut cultivars to diclosulam applied preplant incorporated at 36 g ai/ha in a weed-free environment. Peanut cultivars evaluated included ‘NC 12C’, ‘NC 7’, ‘VAC 92R’, ‘NC-V 11’, ‘NC 10C’, ‘AT VC 1’,‘NC 9’, and the experimental breeding line N90010E. Visible injury 3 wk after planting was less than 5% regardless of cultivar. No injury was observed at 21 d after planting. Diclosulam did not influence the incidence of early leaf spot, late leaf spot, southern stem rot, cylindrocladium black rot, or tomato spotted wilt virus. Diclosulam did not affect percentage of extra large kernels, sound mature kernels, other kernels, and yield. Nomenclature: Diclosulam; peanut, Arachis hypogaea L. NC 12C, NC 7, VAC 92R, NC-V 11, NC 10C, AT VC 1, NC 9, N90010E. Additional index words: Disease interaction, cylindrocladium black rot, Cylindrocladium crotalariae (Loos) Bell et Sobers, early leaf spot, Cercospora arachidicola Hori, late lea...

Evaluation of Selected Runner-Type Peanuts for Plant Stand, Susceptibility to Thrips Injury, and Yield, 1997

Abstract Selected runner-type peanuts, with and without standard insecticide protection, were evaluated for plant stand, TT injury, and yield. ‘GK 7’, ‘Georgia Green’, ‘Andru 93’ and ‘Georgia Runner’ were evaluated and ‘VA-C 92R’ was included as a Virginia-type standard. Peanuts were planted 7 May at the Virginia Tech Tidewater Agric. Res. & Ext. Ctr., Suffolk, VA using 36-inch row spacing. Eight gpa of metam-sodium 42% was injected into rows as a soil fumigant on 11 April, about 4 weeks prior to planting. Thrips protection was provided by Orthene 75 S applied dissolved in water with a CO2 pressurized tractor-mounted sprayer calibrated to deliver 5.0 gap at 24 psi through one SS8001E flat fan nozzle mounted just above planter disks and turned parallel to row direction to deliver the spray fan into the seed furrow. A RCB experimental design was used with 4 replicates; plots were 4 rows by 40 ft. Plant stand was determined by counting all seedlings in the 2 center rows (80 row ft) of each plot on 6 and 19 Jun. TT injury was evaluated on a 0 to 10 scale: 0 = no thrips induced plant injury, 1 = 10% injured leaves, 2 = 20% injured leaves, 3 = 30% injured leaves, 4 = 40% injured leaves, 5 = ≥ 50% injured leaves + ≤5% terminal buds injured, 6 = ≥50% injured leaves + 25% terminal buds injured, 7 = ≥50% injured leaves + 50% terminal buds injured, 8 = ≤ 50% injured leaves + 75% terminal buds injured, 9 = ≥50% injured leaves + ≥90% terminal buds injured, and 10 = dead plants. Yield was determined by digging, drying, and combining peanuts from the 2 center rows of each plot. Data were analyzed using ANOVA and LSD procedures.

Response of Virginia-Type Peanut to Norflurazon

Abstract Four field experiments were conducted in North Carolina from 1994 to 1996 to determine the effect of norflurazon applied preemergence at 1.6 kg ai/ha to virginia-type peanut (Arachis hypogaea L.) cvs. NC 7, NC 9, NC 10C, NC-V 11, VA-C 92R, and AT VC-1. Injury 3 wk after planting was 7% or less in three experiments. Greater injury was noted on VA-C 92R relative to other cultivars in one of these experiments. Injury ranged from 25 to 41% in the fourth experiment, with greater injury noted on NC 9, NC-V 11, and VA-C 92R than on NC 7, NC 10C, or AT VC-1. Norflurazon did not affect peanut maturity, the percentage of extra large kernels, total sound mature kernels, or fancy pods. Norflurazon reduced peanut yield 6% irrespective of cultivars in two of four experiments.

Evaluation of Selected Foliar Applied Insecticides on Potato Leafhopper in Virginia-Type Peanut, 1997

Abstract Selected foliar applied insecticides were evaluated against PLH in Virginia-type peanut. ‘VA-C 92R’ peanut was planted on a producer’s farm in Isle of Wight County, VA using 36-inch row spacing. Foliar treatments were applied on 31 Jul as a full-coverage spray with a CO2-pressurized backpack sprayer calibrated to deliver 14.5 gpa at 50 psi through three D2-13 hollow-cone nozzles per row, one over the top and one on each side of each row. A RCB design was used with 4 replicates. Plots were 4 rows by 40 ft. PLH were sampled by making 5 sweeps per plot with a 15-cm-diameter sweep net and counting numbers of captured adults and nymphs. The pre-treatment sample was not taken on each plot, but was comprised of 20 random 5-sweep samples distributed throughout the planned test area. Data were analyzed using ANOVA and LSD procedures.

Effects of Selected Foliar Applied Insecticides on Thrips Injury and Yield of Virginia-Type Peanut, 1997

Abstract Selected foliar applied insecticides were evaluated against TT injury and for effects on yield of Virginia-type peanut. ‘VA-C 92R’ peanut was planted 7 May at the Virginia Tech Tidewater Agric. Res. & Ext. Ctr., Suffolk, VA using 36-inch row spacing. Eight gpa of metam-sodium 42% was injected into rows as a soil fumigant on 11 Apr, about 4 weeks prior to planting. Foliar sprays were applied on 23 May, after plants had emerged, and again 10 Jun. Sprays were applied in a 12- to 14-inch band over the row with a CO2-pressurized backpack sprayer calibrated to deliver 17.0 gpa at 22 psi through one 8003 E flat nozzle over the top of each row. A RCB design was used with 4 replicates. Plots were 4 rows by 40 ft. TT injury was evaluated based on a 0 to 10 scale where, 0 = no thrips induced plant injury, 1 = 10% injured leaves, 2 = 20% injured leaves, 3 = 30% injured leaves, 4 = 40% injured leaves, 5 = ≥ 50% injured leaves + ≤ 5% terminal buds injured, 6 = ≥ 50% injured leaves + 25% terminal buds injured, 7 = ≥ 50% injured leaves + 50% terminal buds injured, 8 = ≥ 50% injured leaves + 75% terminal buds injured, 9 = a≥ 50% injured leaves + ≥ 90% terminal buds injured, and 10 = dead plants. Yield was determined by digging, drying, and combining peanuts from the 2 center rows of each plot. Data were analyzed used ANOVA and LSD procedures.

Influence of Digging Date on Yield and Gross Return of Virginia-type Peanut Cultivars in North Carolina

Abstract Peanut (Arachis hypogaea L.) growers must balance complex interactions among cultivars, planting dates, environmental and physiological stresses during the growing season, and weather conditions at harvest when determining when to dig peanut. Ten field experiments were conducted in North Carolina from 1994 through 1996 to determine the influence of digging date on pod yield and gross return of virginia-type peanut. Beginning in mid- to late September, the cultivars NC 9, NC 10C, NCV-11, VA-C 92R, AgraTech (AT) VC-1, and NC 12C were dug on four dates approximately 7 d apart. Considerable variation in pod yield and gross return was noted among cultivars and experiments. Delaying digging increased pod yield and gross return in some but not all experiments. Greater variation in pod yield and gross return was observed for NC 10C than for AT VC-1 when compared across digging dates. Pod yield and gross return for NC9, NC V-11, VA-C 92R, and NC 12C were intermediate between NC 10C and AT VC-1. Of the cultivars evaluated, yield and gross return of AT VC-1 were the most stable over digging dates. These data suggest that growers should evaluate maturity of peanut in individual fields for each cultivar when determining when to dig. These data also suggest that factors other than maturity impact pod yield and gross return.

Peanut Response to Prohexadione Calcium as Affected by Cultivar and Digging Date

Abstract An experiment at two locations in 1995 and two locations in 1996 evaluated virginia-type peanut (Arachis hypogaea L.) response to the growth regulator prohexadione calcium (calcium salt of 3,5-dioxo-4-propionylcyclohexanecarboxylic acid) as affected by cultivars and digging dates. Prohexadione calcium at 140 g ai/ha was applied at row closure and again 3 wk later in 1995 or 140 g/ha at row closure and 70 g/ha 3 and 6 wk later in 1996. The cultivars AgraTech (AT) VC-1, NC 9, NC 10C, NC 12C, NC-V11, and VA-C92R were dug on three separate dates approximately 11d apart. Response to prohexadione calcium was independent of digging dates. Prohexadione calcium altered canopy architecture and increased row visibility at harvest for all cultivars although the response was greatest with NC-V 11 and least with NC 9. Prohexadione calcium hastened pod maturity, increased percentages of extra large kernels, total sound mature kernels, and fancy pods, and increased peanut value/kg irrespective of cultivars and digging dates. Yield response to prohexadione calcium was cultivar dependent. NC 9 was most responsive, with yield increased 7 to 16% at all locations. Yields of ATVC-1, NC 10C, NC 12C, and NC-V 11 were increased 9 to 15% at two locations and unaffected at two locations. VA-C 92R was the least responsive, with yield increased 5% at two locations and decreased 8% at two locations.

Effects of Selected Seed, Foliar and In-Furrow Applied Insecticides and Planting Date on Thrips Injury, Plant Stand and Yield, 1996

Abstract Selected insecticides applied to peanut planted on 3 dates were evaluated against TT injury and for effects on plant stand and yield of Virginia-type peanut. ‘VA-C 92R’ peanut was planted 25 Apr, 10 May and 20 May at the Virginia Tech Tidewater Agric. Res. & Ext. Ctr., Suffolk, VA using 36-inch row spacing. Granular insecticides were applied into the seed furrow (IF) at planting with tractor-mounted jars calibrated to deliver exact amounts through lid holes via gravity; liquids with a CO2 pressurized tractor-mounted sprayer calibrated to deliver 5 gpa at 24 psi through one SS8001E flat fan nozzle per row mounted just above planter disks and turned parallel to the row direction. Foliar sprays were applied in a 12-to 14-inch band over the row with a CO2-pressurized backpack sprayer calibrated to deliver 17 gpa at 22 psi through one 8003E nozzle per row. Seed treatments were prepared just before planting by gently mixing measured amounts of product and seed in the planter box (PB). A RCB experimental design was used with 4 replicates; plots were 4 rows by 30 ft. Treatments were evaluated by determining plant injury based on a 0 to 10 scale where, 0 = no thrips induced plant injury, 1 = 10% injured leaves, 2 = 20% injured leaves, 3 = 30% injured leaves, 4 = 40% injured leaves, 5 = ≥50% injured leaves + ≤5% terminal buds injured, 6 = ≥50% injured leaves + 25% terminal buds injured, 7 = ≥50% injured leaves + 50% terminal buds injured, 8 = ≥50% injured leaves + 75% terminal buds injured, 9 = ≥50% injured leaves + ≥90% terminal buds injured, and 10 = dead plants. Plant stand was determined by counting all seedlings in the 2 center rows of each plot (plant date 1-20 May, plant date 2-26 May, plant date 3-3 Jun). Yield was determined by digging, drying and combining peanuts from the 2 center rows of each plot. Data were analyzed within each planting date using ANOVA and LSD procedures.

Effects of Selected Seed, Foliar and In-Furrow Applied Insecticides on Thrips Injury, Plant Stand and Yield, 1996

Abstract Selected insecticides, applied as seed, foliar or in-furrow treatments, were evaluated against TT injury and for effects on plant stand and yield of Virginia-type peanut. ‘VA-C 92R’ peanut was planted 23 Apr at the Virginia Tech Tidewater Agric. Res. & Ext. Ctr., Suffolk, VA using 36-inch row spacing. Granular insecticides were applied into the seed furrow (IF) at planting with tractor-mounted jars calibrated to deliver exact amounts through lid holes via gravity; liquids with a CO2 pressurized tractor-mounted sprayer calibrated to deliver 5 gpa at 24 psi- through one SS8001E flat fan nozzle per row mounted just above planter disks and turned parallel to the row direction. Foliar sprays were applied in a 12- to 14-inch band over the row with a CO2 pressurized backpack sprayer calibrated to deliver 17 gpa at 22 psi through one 8003E nozzle per row. Seed treatments were prepared just before planting by gently mixing measured amounts of product and seed in the planter box (PB). A RCB experimental design was used with 4 replicates; plots were 4 rows by 40 ft. TT injury was evaluated based on a 0 to 10 scale where 0 = no thrips induced plant injury, 1 = 10% injured leaves, 2 = 20% injured leaves, 3 = 30% injured leaves, 4 = 40% injured leaves, 5 = ≥50% injured leaves + ≤5% terminal buds injured, 6 = ≥50% injured leaves + 25% terminal buds injured, 7 = ≥50% injured leaves + 50% terminal buds injured, 8 = ≥50% injured leaves + 75% terminal buds injured, 9 = ≥50% injured leaves + a90% terminal buds injured, and 10 = dead plants. Plant stand was assessed by counting all seedlings in the 2 center rows of each plot (17 May). Yield was determined by digging, drying and combining peanuts from the 2 center rows of each plot. Data were analyzed using ANOVA and LSD procedures.

Selected Granular Insecticide Treatments for Control of Southern Corn Rootworm Injury in Two Peanut Fields, 1996

Abstract Granular insecticides were evaluated for control of SCR pod injury in Virginia-type peanut in 2 fields in Suffolk, VA. The 2 fields selected differed in soil characteristics but were both considered to represent a moderate level of risk to pod damage by SCR. ‘VA-C 92R’ peanuts were planted on 3 May (Field 1) and 23 May (Field 2) using a 36-inch row spacing. All treatments were applied in a 14-inch band over the row with a tractor-mounted Noble granular applicator on 28 June (at the time of early pegging). A randomized complete block experimental design was used with 4 replicates; plots were 4 rows by 200 ft (Field 1) and 4 rows by 180 ft (Field 2). Pod injury was determined 28 Aug and again 25 Sep from all full-sized pods from 5 randomly selected plants per plot. Pods were categorized as immature or mature and as undamaged, scarred (superficial damage to the outer pod wall), or penetrated (pod wall penetrated). Yield was determined by digging, combining, drying and weighing peanuts from the 2 center rows of each plot (400 row ft per plot, 4 Oct - Field 1; 360 row ft per plot, 14 Oct - Field 2). Data were analyzed using ANOVA and LSD statistical procedures.

Laboratory and Field Evaluations of Virginia-Type Peanut Genotypes for Resistance toDiabrotica undecimpunctata howardiBarber (Coleoptera: Chrysomelidae)

Abstract The southern corn rootworm (Diabrotica undecimpunctata howardi Barber) is the primary soil insect pest of peanut (Arachis hypogaea L.) in Virginia and North Carolina. The majority of acreage is planted to recently released cultivars which have not been extensively screened for rootworm resistance. The objectives of this study were to evaluate five virginia-type cultivars (NC-V 11, VA-C 92R, VA 93B, NC 10C, and AgraTech VC-1) and 19 breeding lines for resistance to southern corn rootworm and develop efficient resistance laboratory and field screening techniques for peanut. Laboratory-grown seedlings and pegs, and immature and mature pods taken from field-grown plants were used in bioassays. Neonates from a laboratory colony were reared to the adult stage on plant tissues and evaluated for mortality. Pod damage was determined from field studies where plants were exposed to natural southern corn rootworm infestations. With seedling feeding, NC 6 resulted in significantly more rootworm mortality as c...

Effects of Selected Foliar and In-Furrow Applied Insecticides on Thrips Injury, Plant Stand and Yield of Virginia Peanut, 1995

Abstract Efficacy of selected insecticides, applied as in-furrow or foliar treatments, was evaluated against TT injury and for effects on plant stand and yield of Virginia-type peanut. ‘VA-C 92R’ peanuts were planted 4 May at the Virginia Tech Tidewater Agric. Res. & Ext. Ctr., Suffolk, VA., using 36-inch row spacing. Granular insecticides were applied into the seed furrow (IF) at planting with tractor-mounted jars calibrated to deliver exact amounts through lid holes via gravity; liquids with a CO2 pressurized tractor-mounted sprayer calibrated to deliver 5 gpa at 24 psi through one SS8001E flat fan nozzle per row mounted just above planter disks and turned parallel to the row direction. Foliar sprays were applied in a 12- to 14-inch band over the row with a CO2 pressurized backpack sprayer calibrated to deliver 17 gpa at 22 psi through one 8003E nozzle per row. A RCB experimental design was used with 4 replicates; plots were 4 rows by 40 ft. Treatments were evaluated by determining plant injury based on a 0 to 10 scale where 0 = no thrips induced plant injury, 1 = 10% injured leaves, 2 = 20% injured leaves, 3 = 30% injured leaves, 4 = 40% injured leaves, 5 = ≥50% injured leaves + ≤5% terminal buds injured, 6 = ≥50% injured leaves + 25% terminal buds injured, 7 = ≥50% injured leaves + 50% terminal buds injured, 8 = ≥50% injured leaves + 75% terminal buds injured, 9 = ≥50% injured leaves + ≥90% terminal buds injured, and 10 = dead plants. Injury data for 25 May was recorded before foliar band treatments had been applied. Plant stand was determined by counting the plants in the 2 center rows of each plot. Yield was determined from digging, drying and combining peanuts from the 2 center rows of each plot. Data were analyzed using ANOVA and LSD procedures.

Evaluation of Virginia-type Peanut Cultivars for Resistance to Southern Corn Rootworm1

Abstract Southern corn rootworm (SCRW) (Diabrotica undecimpunctata howardi Barber) is the most damaging soil insect to peanut (Arachis hypogaea L.) in the Virginia-North Carolina production area. New cultivars and advanced breeding lines have not been evaluated for resistance to SCRW. The objective of this 3-yr study was to evaluate three new cultivars (NC-V 11, VA-C 92R, and Agra Tech VC-1) and an advanced breeding line (VA 861101) for resistance to SCRW. NC 6 and NC 9 were used as resistant and susceptible checks, respectively. Pod damage, yield, market grade, and dollar value were obtained for each plot. Agra Tech VC-1, VA-C 92R, and VA 861101 had less total pod damage from SCRW than NC 9. VA 861101 produced significantly higher yields and value per ha than all cultivars on soil types conducive to SCRW damage. Insecticidetreated plots had significantly higher value per ha and lower total pod damage than untreated plots. Results from this study indicate that VA 861101 may be an acceptable replacement for NC 6. Agra Tech VC-1 is the most resistant of the newly released cultivars, but this is not reflected in higher yields.

Diamond-shaped Seeding of Six Peanut Cultivars1

Abstract Intrarow seed spacing of peanut (Arachis hypogaea L.) has been studied extensively using conventional interrow widths. Modification of spatial arrangements of cultivars with different growth habits can result in optimizing yield. The objective of this study was to determine the effects of seeding in a diamond-shaped configuration on the yield, value, market grade, and plant growth of six peanut cultivars. A 3-year field study was conducted at the Tidewater Agricultural Research and Extension Center, Suffolk, Virginia, using NC 7, VA 81B, NC 9, NC-V 11, VA-C 92R and Florigiant peanut. Plots were 1.82-m wide and 3.65-m long with diamond-shaped seed configurations of 15.2 × 15.2, 30.5 × 30.5, and 45.7 × 45.7 cm. The experimental design was a randomized complete block, split-plot design with cultivars the main plot and seed configurations the split-plot with four replications. Significantly taller main stems (39.4, 30.5, and 22.9 cm) and longer cotyledonary lateral branches (50.3, 48.0, and 45.5 cm) were recorded for the 15.2 × 15.2, 30.5 × 30.5, and 45.7 × 45.7-cm diamond-shaped seed configurations, respectively. The 15.2 × 15.2-cm seed configuration resulted in higher yield, value, sound mature kernels, and total kernels and lower percentage of other kernels. The 15.2 × 15.2, 30.5 × 30.5, and 45.7 × 45.7-cm seed configurations had yields of 5935, 5497, and 4874 kg ha-1 and values of 4192, 3804, and 3342 $ ha-1, respectively. Sound mature kernels were 69.7, 68.2 and 67.4% and total kernels were 73.2, 72.3, and 71.8% for the 15.2 × 15.2, 30.5 × 30.5, and 45.7 × 45.7-cm seed configurations, respectively. Percentages of other kernels were 1.7, 2.0, and 2.3 for the 15.2 × 15.2, 30.5 × 30.5, and 45.7 × 45.7-cm seed configurations, respectively. Significant cultivar by seed configuration interactions were obtained for yield and value. These results indicate peanut yields can be increased by selecting cultivars which respond to diamond-shaped seed configurations or more importantly that seeding rate and configuration should be matched to the cultivar selected.