Three experiments were conducted at Lewiston-Woodville, NC in 1999 and 2000 to evaluate weed management systems in strip-tillage peanut. Using a factorial treatment arrangement, flumioxazin was evaluated with standard preemergence (PRE), early postemergence (EPOST), and postemergence (POST) herbicides. Dimethenamid PRE controlled common lambsquarters 77%, eclipta 32 to 100%, prickly sida 14%, and entireleaf, ivyleaf, and pitted morningglory no more than 23%. The addition of flumioxazin PRE to dimethenamid controlled common lambsquarters 97%, eclipta 57 to 100%, prickly sida 79%, and morningglory species 44 to 100%. Common lambsquarters, eclipta, prickly sida, yellow nutsedge, and entireleaf, ivyleaf, and pitted morningglory were controlled at least 96% with dimethenamid plus flumioxazin PRE followed by (fb) paraquat plus bentazon EPOST fb imazapic POST. Peanut injury from dimethenamid PRE alone or in PRE tank mixture with flumioxazin ranged from 0 to 60%, but did not significantly affect yield. Season-long control of goosegrass and large crabgrass required a late POST treatment of clethodim.
Peanut growers throughout the Southeastern Coastal Plain have traditionally utilized conventional tillage systems but are increasing conservation tillage production systems. Growers practicing conservation tillage (including minimum, strip, and no-till) plant peanut directly into residue left by winter cover crops or winter native vegetation. The resulting plant residue left on the surface of the soil protects the soil structure, and aids in reducing erosion in the sandy soils of the Southeastern Coastal Plain (
Reports differ on overall peanut yields in conventional versus conservation peanut production.
Flumioxazin (formerly S-53482 and V-53482), is a soil-applied herbicide used PRE for broadleaf weed control in peanut and soybean [
The objective of this research was to evaluate weed control, crop injury, and peanut yield when flumioxazin was applied in combination with PRE and POST herbicides commonly used in strip tillage peanut production.
Field experiments were conducted in three locations at the Peanut Belt Research Station located near Lewiston-Woodville, NC in 1999 and 2000 to evaluate weed management systems in strip-tillage peanut. Peanut cultivars ‘NC 10 C’ in 1999 and ‘NC 12 C’ in 2000 were planted 8 cm deep in rows spaced 91 cm wide. Peanuts were planted at 120 to130 kg/ha in early May of both years. Plots measured 6.1 m long and 3.6 m wide, and were arranged in a randomized complete block design with three replications of treatments. Lewiston-Woodville soils are classified as Norfolk sandy loams (fine-loamy, siliceous, thermic Typic Kandiudults) with 1.0% organic matter and pH 5.9 to 6.1.
Paraquat at 0.7 kg ai/ha was applied to all plots 3 wk before planting to control existing vegetation. The PRE herbicide options included: (1) paraquat at 0.7 kg/ha plus dimethenamid at 1.4 kg ai/ha, (2) paraquat at 0.7 kg/ha plus dimethenamid at 1.4 kg/ha plus flumioxazin at 71 g ai/ha or (3) paraquat at 0.7 kg/ha plus flumioxazin at 71 g/ha. At the time of PRE treatment, broadleaf weeds were in the cotyledon to three-leaf stage, and weed densities ranged from 2 to 50 per m2 depending on species (data not shown). For those plots that received an EPOST herbicide treatment, paraquat at 145 g/ha plus bentazon at 0.28 kg ai/ha was applied approximately 15 days after planting. Weed stage and density at time of EPOST was cotyledon to 5-leaf growth stage at densities from 10 to 20 plants per species (data not shown). POST treatments were applied two weeks after the EPOST treatments. At the time of POST treatments, broadleaf weeds were in the cotyledon to seven-leaf stage, and weed densities ranged from 2 to 30 per m2 depending on species (data not shown). POST herbicide options included: (1) a prepackaged mixture
A nonionic surfactant
Peanut injury ratings, based on visual estimations of discoloration, stunting and stand reduction, were made 4 and 12 weeks after planting (WAP). Visual estimates of weed control were recorded early (mid-June) and late season (late August) approximately one month prior to harvest. Weed control and peanut injury ratings were based upon visual estimations of leaf discoloration and biomass reduction when compared to the nontreated control. Ratings are based on a scale of 0 (no injury symptoms) to 100 (complete death of all plants or no plants present) (
Because there were only minor differences in weed control between the two ratings, and weed pressure late in the season is more influential on peanut yield and harvesting efficiency, only the late season ratings are presented
Data were pooled over location and years for those species for which no treatment by location interaction was found, but weed responses to herbicides are discussed separately by location/year in cases where a treatment by location interaction occurred.
There was no location by treatment interaction for this weed species; therefore the data were combined over locations and years (
There were treatment by location interactions for control of ivyleaf and pitted morningglories; therefore the data are discussed separately. Entireleaf morningglory (
There was a location by herbicide interaction; therefore each location is discussed separately. Dimethenamid or flumioxazin PRE or in PRE tank mixture controlled eclipta variably (
No treatment by location interactions were present for goosegrass or large crabgrass; therefore the data were combined over locations (data not shown). Dimethenamid PRE controlled goosegrass 95% and large crabgrass 97% initially. However a late application of clethodim was needed for season-long control and to facilitate harvest (≥99% control for both weed species at all locations). Clethodim controls goosegrass and large crabgrass (
No treatment by location interactions were seen for prickly sida control; therefore the data were combined over locations (
There were treatment by location interactions for yellow nutsedge control, thus each location will be discussed separately. Control by most herbicides was greater in Lewiston-Woodville 2000B than in the other locations. Yellow nutsedge populations at Lewiston 2000B were approximately 10 to 15 plant/m2 while at other locations they ranged from 30 to 50 plants/m2 (data not shown). Dimethenamid PRE alone controlled yellow nutsedge by 57 to 100% depending on location (
There was a treatment by location interaction for peanut injury (P < 0.05), therefore data are discussed by location. Overall peanut injury was based upon stand reduction due to stunting, leaf discoloration, and spots of necrosis (data not shown). Injury was very erratic, and in 1999 there was no visible injury (
Location interactions were significant: therefore, each location is discussed separately. Peanut treated with dimethenamid PRE yielded 1,520 to 3,320 kg/ha, depending on location (
The authors wish to thank Dr. Cavell Brownie, professor of Statistics, North Carolina State University for statistical assistance. Appreciation is also extended to the station personnel at the Peanut Belt Research Station for their assistance in this research and to the North Carolina Peanut Grower's Association and Valent USA for partial funding of this research.
Received for publication Date and in revised form Date.
Storm®, 29% bentazon, and 13.4% Acifluorfen. BASF Corporation. Agricultural Products Group, PO Box 13528, Research Triangle Park, NC 27709.
Induce nonionic low foam wetter-spreader adjuvant containing 90% non-ionic surfactant (alkylarylopolyoxyalkane ether and isopropanol), free fatty acids, and 10% water. Helena Chemical Company, Suite 500, 6075 Poplar Avenue, Memphis, TN 38137.