bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial Patterning and Site Occupation at Likoaeng, an Open‐Air Hunter‐Gatherer Campsite in the Lesotho Highlands, Southern Africa
Authors: Mitchell Peter , Plug Ina , Bailey Geoff
Published: July 2006

Archaeologists studying southern African hunter‐gatherers are increasingly interested in investigating issues of broader anthropological interest, including gender relations, the ways in which people organized their living space, and the sharing of food. With this interest has come the recognition that rockshelter deposits may hold limited potential for the exploration of these questions because of the palimpsest effects and disturbance created by repeated occupations. Attention is therefore turning to open‐air living sites, among which those with temporally discrete occupations are particularly important. We report here on the preliminary analysis of spatial patterning from one such occupation at a multiphase hunter‐gatherer campsite on the banks of the Senqu River, Lesotho. Here the distributions of artifacts (principally, but not exclusively, of stone) are examined, related to the presence of features present at the site, and interpreted.
Risk Factors for Congenital Cytomegalovirus Infection in the Offspring of Young Women: Exposure to Young Children and Recent Onset of Sexual Activity
Authors: Fowler Karen B. , Pass Robert F.
Published: July 2006

OBJECTIVE. Two recognized sources of maternal cytomegalovirus infection are young children and sexual activity. Previous studies evaluated either maternal exposures to young children or sexual activity, but these studies did not evaluate whether both of these maternal cytomegalovirus sources contribute to increases in congenital cytomegalovirus infections within populations with a high prevalence of infection among women of childbearing age. Our objective with this study was to investigate whether maternal cytomegalovirus exposure through young children and by sexual activity increases the risk for congenital cytomegalovirus infection in their offspring.

METHODS. A case-control study of 519 women from a delivery population in Birmingham, AL, between December 1992 and July 1998 was undertaken to measure the association between maternal cytomegalovirus exposures and an increased risk for congenital cytomegalovirus infection in their infants. Routine newborn cytomegalovirus screening at the hospital identified infants with congenital cytomegalovirus infection. The cases (n = 150) were women who delivered an infant with congenital cytomegalovirus infection, and the control subjects (n = 369) were randomly selected from the delivery population of women whose newborns were uninfected. Investigation of exposures included using a standardized maternal interview, prenatal and medical chart abstraction, and laboratory confirmation of cytomegalovirus infection.

RESULTS. Significant associations between congenital cytomegalovirus infection and caring for preschool children in the year before delivery, onset of sexual activity <2 years before delivery, sexually transmitted diseases during pregnancy, household size >3 people, and maternal age <25 years were identified. Women who cared for preschool children in the year before delivery and also became sexually active within the 2 years before delivery were at greatest risk for delivering an infant with congenital cytomegalovirus infection.

CONCLUSIONS. Caring for young children and recent onset of sexual activity contribute to an increased risk for congenital cytomegalovirus infection in the offspring of young women.
Persistent Humoral Immune Defect in Highly Active Antiretroviral Therapy–Treated Children With HIV-1 Infection: Loss of Specific Antibodies Against Attenuated Vaccine Strains and Natural Viral Infection
Authors: Bekker Vincent , Scherpbier Henriëtte , Pajkrt Dasja , Jurriaans Suzanne , Zaaijer Hans , Kuijpers Taco W.
Published: July 2006

OBJECTIVE. In the pre–highly active antiretroviral therapy era, a loss of specific antibodies was seen. Our objective with this study was to describe the loss of specific antibodies during treatment with highly active antiretroviral therapy.

METHODS. In a prospective, single-center, cohort study of 59 children with HIV-1 infection, we investigated the long-term effect of highly active antiretroviral therapy on the titers and course of specific antibodies against measles, mumps, and rubella vaccine strains compared with wild-type varicella zoster virus, cytomegalovirus, and Epstein-Barr virus.

RESULTS. During highly active antiretroviral therapy, age-adjusted CD4+ T cells and B cells increased, whereas total immunoglobulin levels declined. Although these children were preimmunized before the start of highly active antiretroviral therapy, only 24 (43%) had antibodies against all 3 measles, mumps, and rubella. Antibodies against measles, mumps, and rubella were lost in 14 (40%), 11 (38%), and 5 (11%) children who were seropositive at baseline. We also observed loss of varicella zoster virus immunoglobulin G in 7 (21%) of 34, cytomegalovirus immunoglobulin G in 3 (7%) of 45, but none of 53 Epstein-Barr virus–seropositive children. During highly active antiretroviral therapy, primary vaccination in 3 patients and 15 revaccinations in those with negative serology demonstrated incomplete seroconversion.

CONCLUSIONS. Humoral reactivity in children with HIV-1 infection remains abnormal during highly active antiretroviral therapy. Despite immune reconstitution, antibodies against live-attenuated vaccine and wild-type natural virus strains disappear over time in up to 40% of children with HIV-1 infection.
The “Slurp” Test: Bedside Evaluation of Bulbar Muscle Fatigue
Authors: Hudspeth Michelle P. , Holden Kenton R. , Crawford Thomas O.
Published: July 2006

Patients with myasthenia gravis or other neuromuscular disorders are subject to increasing weakness of bulbar-innervated muscles, with resulting aspiration or catastrophic airway compromise. The available practical assessments of bulbar function in children are inadequate. We report our experience with the “slurp” test, a new bedside measure of bulbar function, in children with myasthenia gravis. Our experience suggests that the test is valuable for identifying patients with probable serious compromise of bulbar function, for monitoring such children during times of intercurrent illness, and for guiding therapy.
Conidial Pigmentation Is Important to Tolerance Against Solar‐simulated Radiation in the Entornopathogenic Fungus Metarhizium anisopliae
Authors: Brags Gilberto U. L. , Rangel Drauzio E. N. , Flint Stephan D. , Anderson Anne J. , Roberts Donald W.
Published: July 2006

The importance of conidial pigmentation to solar UV radiation tolerance in the entomopathogenic fungus Metarhizium anisopliae var. anisopliae, was estimated by comparing the effects of exposure to simulated solar UV radiation on the wild‐type parent strain U.S. Department of Agriculture (USDA)‐Agri‐cultural Research Service (ARS) Collection of Entomopathogenic Fungal Cultures (ARSEF) 23, which has dark green conidia, and three groups of color mutants with yellow, purple and white conidia. The comparisons included inactivation levels and the kinetics of germination of conidia exposed or not exposed to simulated solar UV radiation. In addition to significantly inactivating the conidia of different mutants, exposure to radiation delayed for several hours the germination of surviving conidia of the wild type and all mutants. In general, mutants with white conidia were more sensitive to simulated solar UV radiation than mutants with purple conidia, which were more sensitive than mutants with yellow conidia, which in turn were more sensitive than the green wild strain. A significant variation in tolerance to simulated solar radiation was observed among mutants within each color group, particularly among mutants with yellow conidia. Revertants with green conidia, DWR 179 and DWR 176, were obtained from the very sensitive UV mutants DWR 148 (yellow conidia) and DWR 149 (purple conidia), respectively. These revertants had levels of tolerance to simulated solar UV radiation similar to those of the wild‐type ARSEF 23. This observation is strong evidence of the importance of green conidial pigmentation for tolerance to simulated solar UV radiation, a factor that could be manipulated to produce M. anisopliae strains with more tolerance to solar UV radiation.
Microwave Treatment of Eight Seconds Protects Cells of lsafis indigofica from Enhanced UV‐8 Radiation Lesions
Authors: Chen Yi‐Ping
Published: July 2006

To determine the role of microwaves in the stress resistance of plants to enhanced ultraviolet‐B (UV‐B) radiation, Isatis indigotica Fort. seeds were subjected to microwave radiation for 8 s (wavelength 125 mm, power density 1.26 mW mm‐2, 2450 MHz). Afterwards they were cultivated in plastic pots in an artificial‐glass greenhouse maintained at 25°C, 70% relative humidity, and 400 pmol mol‐1 CO2, under visible‐light conditions of 1500 pmol m‐2 s‐l for 8 h day‐1. When the seedlings were 10 days old, they were subjected to 10.08 kJ m‐2 UV‐B (PAR: 220 μmol m‐2 s‐1) radiation for 8 days. Changes in a number of physiological and biochemical characteristics and in the thermal decomposition enthalpy of biomass were measured and used as indicators of the protective capacity of microwave radiation in this experiment. Our results revealed that microwave pretreatment of seeds enhanced UV‐B stress resistance in the seedlings by decreasing the concentration of malondialdehyde (MDA) and increasing the concentration of ascorbic acid (AsA) and UV‐B‐absorbing compounds, increasing the activities of catalase (CAT), per‐oxidase (POD), and superoxide dismutase (SOD), and increasing the energy accumulation of photosynthesis. All these results suggest that microwave radiation enhances plant metabolism and results in increased UV‐B stress resistance. This is the first investigation reporting the use of microwave pretreatment to protect the cells of Isatis indigotica from UV‐B‐induced lesions.
The Effect of Herbicides and Crop Rotation on Weed Control in Glyphosate-Resistant Crops
Authors: Tingle C. H. , Chandler J. M.
Published: July 2006

Field studies were conducted from 1998 through 2000 to determine the influence of crop rotation and level of herbicide system for johnsongrass, entireleaf morningglory, and smellmelon control in glyphosate-resistant cotton and corn. Three different crop rotation schedules were used including cotton–cotton–cotton, cotton–corn–cotton, and corn–cotton–corn. Herbicide systems involving various degrees of input levels (low, medium, and high) were compared with a conventional standard program. In 1998, weed control ranged from 80 to 95% for all herbicide systems when the rotation was corn–cotton–corn. In 1999 and 2000, the low-input herbicide system controlled entireleaf morningglory 76 to 78% late in the season. Decreased smellmelon control (78%) was also observed with the conventional standard during this same period. In the cotton–corn–cotton rotation, late-season entireleaf morningglory control decreased each year in the low-input system, regardless of crop. In 2000, late-season evaluations indicated lower weed control of all three species with the conventional standard program compared with the other input systems. Yield data from 2000 suggested that corn and seed cotton yields were influenced by crop rotation.
Control of Volunteer Glyphosate-Resistant Corn (Zea mays) in Glyphosate-Resistant Soybean (Glycine max)
Authors: Deen William , Hamill Allan , Shropshire Christy , Soltani Nader , Sikkema Peter H.
Published: July 2006

Volunteer corn in soybean can reduce yields, interfere with harvest, and cause unacceptable levels of contamination by its presence in the harvested soybean. In Ontario, soybean frequently follow corn in rotation. The use of glyphosate-resistant corn and soybean varieties has increased dramatically in Ontario. Field studies were conducted at two locations in southwestern Ontario to determine whether quizalofop-p-ethyl, clethodim, and fenoxaprop-p-ethyl can be tank mixed with glyphosate to provide effective control of volunteer glyphosate-resistant corn in glyphosate-resistant soybean. Soybean plots were overseeded with glyphosate-resistant corn and treatments consisting of glyphosate applied alone and tank mixed with full and reduced rates of each graminicide with and without a recommended surfactant. Tank mixing the graminicides and adjuvants with glyphosate did not affect glyphosate weed control or crop tolerance. Use of a recommended adjuvant significantly improved the effectiveness of the graminicides, particularly when reduced rates were applied. Quizalofop-p-ethyl was the most effective graminicide for controlling glyphosate-resistant volunteer corn, followed by clethodim and fenoxaprop-p-ethyl.
Italian Ryegrass (Lolium multiflorum) Control in Imidazolinone-Resistant Wheat
Authors: Clemmer Kevin C. , York Alan C. , Brownie Cavell
Published: July 2006

Imazamox ammonium salt at 53 g ae/ha applied postemergence in the fall to imidazolinone-resistant wheat controlled Italian ryegrass 98 to 100% 10 wk after treatment (WAT). Control 22 WAT was 88 to 98% at two locations and 55% at a third location. Imazamox was more effective applied in fall to three- to four-leaf Italian ryegrass than when applied in spring to one- to three-tiller Italian ryegrass. Split applications, with 27 g/ha applied in fall and spring, were no more effective than 53 g/ha applied in fall. Pendimethalin preemergence in combination with fall-applied imazamox increased control 22 WAT 10 to 33 percentage points at two of three locations. Imazethapyr ammonium salt plus imazapyr isopropylamine salt applied at 47 plus 16 g ae/ha and imazamox at 44 or 53 g/ha were similarly effective, whereas imazethapyr at 70 g/ha was ineffective. Control by imazapic ammonium salt at 70 g ae/ha was equal to or greater than control by imazamox at 44 or 53 g/ha. Imazamox, imazethapyr plus imazapyr, and imazapic controlled diclofop-resistant and -susceptible Italian ryegrass. Thifensulfuron plus tribenuron mixed with imazamox increased Italian ryegrass control in field and greenhouse experiments, whereas dicamba reduced control compared with imazamox applied alone. Control by imazamox plus 2,4-D was similar to or greater than control by imazamox alone.
Effect of Cogongrass (Imperata cylindrica) Extracts on Germination and Seedling Growth of Selected Grass and Broadleaf Species
Authors: Koger Clifford H. , Bryson Charles T.
Published: July 2006

The effects of cogongrass foliage and root residue extracts on germination and radicle and coleoptile growth of barnyardgrass, browntop millet, bermudagrass, hemp sesbania, Italian ryegrass, and prickly sida were investigated in laboratory experiments. Liquid extracts of cogongrass foliage and root residues at concentrations of 0, 0.25, 0.5, 1, 2, 4, and 8% were evaluated on bermudagrass and Italian ryegrass. Effects of 8% foliage or root residue extracts were investigated on hemp sesbania, prickly sida, barnyardgrass, and browntop millet. Cogongrass residue (foliage and root) extracts at concentrations as low as 0.5% inhibited germination and seedling growth of bermudagrass and Italian ryegrass. Germination of bermudagrass and Italian ryegrass was reduced by as much as 62% and radicle and coleoptile growth by as much as 96% at the highest extract concentrations. Foliage and root residue extracts reduced germination of barnyardgrass, browntop millet, and prickly sida 52 to 64% and seedling growth by as much as 96%. Cogongrass extracts had no effect on germination or seedling development of hemp sesbania. Results indicate that extracts of cogongrass may contain allelochemicals that may contribute to its invasiveness and extreme competitiveness.
Egyptian Broomrape (Orobanche aegyptiaca) Control in Tomato with Sulfonylurea Herbicides—Greenhouse Studies
Authors: Eizenberg Hanan , Goldwasser Yaakov , Golan Shmuel , Plakhine Dina , Hershenhorn Joseph
Published: July 2006

Broomrapes (Orobanche spp.) are root holoparasitic plants that cause severe damage to economically important crops, especially in Mediterranean countries. Egyptian broomrape is the most troublesome weed on tomatoes grown for processing in Israel. In the present study, we tested the efficacy and selectivity of four sulfonylurea herbicides in controlling Egyptian broomrape on tomatoes grown in pots under greenhouse conditions. MON 37500, rimsulfuron, HOE 404 and SL-160 were applied postemergence (POST) and preplant incorporated (PPI) followed by POST applications. MON 37500 and rimsulfuron were more selective to tomato and controlled the parasite more effectively than HOE 404 and SL-160. MON 37500 and rimsulfuron at 50 and 100 g ai/ha and at 100, 150, and 200 g ai/ha, respectively, applied on tomato foliage 14, 28, and 42 d after planting (DAP) and followed by sprinkler irrigation to field capacity, resulted in complete control of the parasite. However, a significant reduction in control efficacy was observed when the experiment was repeated with charcoal-topped pots, suggesting that the herbicides act mainly through the soil. Except for rimsulfuron, the PPI followed by two POST treatments was more phytotoxic to tomato plants than the POST treatments. The PPI plus POST applications controlled Egyptian broomrape effectively, but tomato plants were injured by HOE 404 at all PPI application rates and by MON 37500 at the high rate at 150 g/ha. The present study determined that three POST applications or a PPI application followed by two POST applications of MON 37500 at 50 or 100 g/ha, or rimsulfuron at 100, 150, or 200 g/ha were effective and selective in controlling Egyptian broomrape on tomato, under greenhouse conditions.
Soil pH and Cation Exchange Capacity Affects Sunflower Tolerance to Sulfentrazone
Authors: Kerr Gregory W. , Stahlman Phillip W. , Dille J. Anita
Published: July 2006

Effects of soil pH and cation exchange capacity (CEC) on sunflower tolerance to sulfentrazone were investigated in a greenhouse study. Variables were soil pH (7.0, 7.3, 7.5, and 7.8), soil CEC (8.2, 13.7, 18.4, and 23.3 cmol/kg), and sulfentrazone rate (0, 105, 158, and 184 g ai/ha). Sulfentrazone-induced leaf chlorosis was affected by soil pH at 12 d after planting (DAP), but plants recovered, and earlier differences were not visible 9 d later. At 12 DAP, leaf chlorosis was 3 or 4% more severe in soils with pH 7.3 or higher compared with soils with pH 7.0 when averaged over both sulfentrazone rate and soil CEC. Leaf chlorosis resulting from sulfentrazone rates of 105, 158, and 184 g/ha was 17, 25, and 35% less at 23 cmol/kg than at 8.2 cmol/kg, respectively. Differences in chlorosis among sulfentrazone rates were greatest in soil with low CEC and lessened as soil CEC increased. Plants regained normal color over time, and newly emerging leaves were not affected. However, plant dry weights were reduced when sulfentrazone rate was ≥158 g/ha. Averaged over sulfentrazone rate and soil pH, sunflower dry weights were less when soil CEC was 8.2 compared with a CEC of 13.7 cmol/kg or higher, indicating a greater response at low CEC. Sunflower plant dry matter was not different in sulfentrazone-treated soil with a CEC above 13.7 cmol/kg. At the ranges tested, soil CEC had a considerably greater effect than did pH on sunflower tolerance to sulfentrazone.
Tolerance of Six Soft Red Winter Wheat Cultivars to AE F130060 00 Plus AE F115008 00
Authors: Crooks H. Lane , York Alan C. , Jordan David L.
Published: July 2006

Tolerance of six soft red winter wheat cultivars to AE F130060 00 plus AE F115008 00 applied at 12.5 plus 2.5 g ai/ha and 25 plus 5 g ai/ha, respectively, at the two- to three-tiller stage was examined under weed-free conditions at four locations over 2 yr. Visible injury averaged 5 and 15% 3 wk after treatment (WAT) in years 1 and 2, respectively. Injury was 2% or less 10 WAT. No differences among cultivars were noted for visible injury, and AE F130060 00 plus AE F115008 00 did not reduce grain yield in year 1. In year 2, averaged over herbicide rates, grain yields of the cultivars ‘Coker 9663’, ‘Pioneer 2580’, ‘Coker 9704’, ‘Pioneer 2684’, ‘FFR 555’, and ‘Jackson’ were reduced 3, 5, 6, 8, 10, and 16%, respectively. The yield reduction for Jackson was different from those for the other cultivars. Yield reduction was attributed to reduced numbers of kernels per spike.
Germination of Various Weed Species in Response to Vetiver Oil and Nootkatone
Authors: Mao Lixin , Henderson Gregg , Laine Roger A.
Published: July 2006

Germination experiments were conducted in petri dishes to test the effect of vetiver oil and one of its minor components, nootkatone, on six common weed species. Vetiver oil inhibited germination of redroot pigweed, common lambsquarters, giant ragweed, pitted morningglory, and velvetleaf. Nootkatone, at much higher concentrations than it occurs in the oil, exhibited germination inhibition for all weed species except velvetleaf. Redroot pigweed was the most sensitive species with germination inhibition at 0.1 to 1.0 mg/ml of vetiver oil and nootkatone. At 1.0 to 8.0 mg/ml, nootkatone reduced germination of giant ragweed by 24 to 92%, whereas vetiver oil reduced the germination only by 6 to 11%. Vetiver oil and nootkatone also inhibited seedling expansion of redroot pigweed and common lambsquarters. No significant inhibition of germination and seedling expansion was found for sicklepod. These laboratory studies provide preliminary evidence that nootkatone and vetiver oil may have use as herbicides.
Weed Management in Cotton with CGA-362622, Fluometuron, and Pyrithiobac
Authors: Burke Ian C. , Wilcut John W.
Published: July 2006

An experiment was conducted at five locations in North Carolina during 2000 and 2001 to evaluate weed control, crop injury, and cotton yield. Weed management systems included different combinations of pyrithiobac preemergence (PRE), fluometuron PRE, CGA-362622 postemergence (POST), pyrithiobac POST, and monosodium salt of methylarsonic acid (MSMA) plus prometryn applied late POST-directed (LAYBY). At Goldsboro in 2000, cotton was injured 74 to 78% by CGA-362622 POST when evaluated 4 to 7 d after treatment (DAT). Injury at Clayton, Goldsboro, and Lewiston in 2001 and Rocky Mount in 2000 was less than 16% 4 to 7 DAT with the same treatment and was not apparent by 62 DAT. CGA-362622 controlled common lambsquarters, common ragweed, Palmer amaranth, sicklepod, smooth pigweed, andIpomoeaspecies including entireleaf, ivyleaf, and pitted morningglory, and the addition of pyrithiobac to the herbicide system, either PRE or POST, increased control ofAmaranthusspecies, jimsonweed, and prickly sida. CGA-362622 did not control jimsonweed or prickly sida. Fluometuron PRE, pyrithiobac PRE, and MSMA plus prometryn LAYBY were beneficial for increasing weed control and cotton lint yields. Prometryn plus MSMA LAYBY increased control of common ragweed, entireleaf morningglory, jimsonweed, pitted morningglory, and smooth pigweed and provided higher cotton yields than similar systems without a LAYBY. The greatest weed control and greatest cotton lint yields required complete weed management systems that included a combination of PRE, POST, and LAYBY treatments.
In-Row and Between-Row Interference by Corn Modifies Annual Weed Control by Preemergence Residual Herbicide
Authors: Donald William W. , Johnson William G. , Nelson Kelly A.
Published: July 2006

The presence of row crops, such as field corn, improves herbicidal control of weeds, but the impact of crop row position on herbicide dose–response relationships for weeds is unknown. At midseason at three site-years in Missouri, total weed cover (WC) was reduced by increasing soil residual herbicide rate in a dose-dependent response and was as much as 20% lower in-row (IR) than between-row (BR). Preemergence atrazine +S-metolachlor + clopyralid + flumetsulam at different rates (0×, 0.25×, 0.5×, 0.75×, and 1×, where 1× rate was 2,240 + 1,750 + 210 + 67 g ai/ha, respectively) were applied at planting in field corn to control giant foxtail, the chief weed present, and annual broadleaf weeds, largely common waterhemp. Lower herbicide rates were required to reduce IR WC to the same extent as BR WC, but these rates varied between site-years. At all three site-years, a least squares regression equation adequately described data variability relating corn yield to IR or BR WC (or both) (i.e., Y = a + bBR2, where Y is corn yield in kg/ha, BR is BR WC [%], and a and b are coefficients).
Weed Management in Glyphosate Resistant Soybean: Weed Emergence Patterns in Relation to Glyphosate Treatment Timing
Authors: Hilgenfeld Kari L. , Martin Alex R. , Mortensen David A. , Mason Stephen C.
Published: July 2006

Knowing when weed species are likely to emerge can aid in developing effective integrated weed management programs. When using nonresidual herbicides such as glyphosate for weed control, treatment timing is critical. This study characterized the emergence patterns of common lambsquarters, common sunflower, common waterhemp, eastern black nightshade, ivyleaf morningglory, shattercane, and woolly cupgrass in soybean, in relation to common glyphosate application timings. Approximately 90% or more of common lambsquarters, common sunflower, and common waterhemp seedlings emerged before the end of May, both in 2000 and 2001. Both ivyleaf morningglory and shattercane emerged from late April to mid-August, allowing these species to avoid glyphosate applications timed to prevent early-season weed competition. Avoidance through periodicity in emergence underscores the importance of integrating multiple tactics to ensure that difficult to manage weeds are not selected for in this management system.
Weed Management in a Glyphosate Resistant Soybean System: Weed Species Shifts
Authors: Hilgenfeld Kari L. , Martin Alex R. , Mortensen David A. , Mason Stephen C.
Published: July 2006

With increased reliance on glyphosate for weed control, weed species composition shifts are likely. Changes in relative abundance could arise from differential tolerance or resistance to, or avoidance of, glyphosate. This study characterized the potential changes in seedbank composition of a mixed population of summer annual weeds due to glyphosate application timing. Seven weeds common in soybean fields in the Midwest were introduced at known densities and treated with glyphosate at several treatment timings. Common lambsquarters, common sunflower, common waterhemp, eastern black nightshade, ivyleaf morningglory, shattercane, and woolly cupgrass were selected to represent a range of emergence patterns and tolerances to glyphosate. Seedling emergence and seed production were monitored. Differences in herbicide tolerance and avoidance, through markedly different weed emergence patterns, were strong contributors to projected changes in weed species composition. Lessened sensitivity to glyphosate allowed some emerged species, such as ivyleaf morningglory, to better survive the herbicide. Late emergence allowed others, such as shattercane and ivyleaf morningglory, to avoid glyphosate applications. Such mechanisms may allow specific species to increase in a continuous glyphosate system.
Use of Optical Remote Sensing for Detecting Herbicide Injury in Soybean
Authors: Thelen Kurt D. , Kravchenko A. N. , Lee Chad D.
Published: July 2006

Experiments were conducted from 2000 to 2002 at two locations each year to determine if lactofen and imazethapyr injury to soybean could be detected using digital aerial imagery and ground-based optical remote sensing. Lactofen and imazethapyr were applied at base rates of 105 and 71 g/ha, respectively, and at 0, 2X, and 4X rates. Treated plots were evaluated between 7 and 21 d after treatment for crop injury using a ground-based radiometer and a system using computer analysis of digital aerial imagery. Both the ground-based radiometer and the digital aerial imagery were effective in detecting herbicide injury under most conditions. The digital aerial imagery system was found to be more sensitive in detecting herbicide injury than the ground-based radiometer system. Herbicide or herbicide rate had a significant effect on normalized differential vegetation indices (NDVI) derived from digital aerial imagery in four of four site-years. NDVI values derived from a multispectral ground-based radiometer were significant for herbicide or herbicide rate in four of six site-years. NDVI values from treated plots were subtracted from the NDVI value of the untreated check to generate a ΔNDVI. The resulting ΔNDVI values from the ground-based radiometer system were significant for herbicide or herbicide rate in six of six site-years. Neither optical remote-sensing system was effective at estimating actual application rates of lactofen and imazethapyr across a broad range of field and weather conditions due to temporal and spatial variability in crop response to the herbicides.
Trumpetcreeper (Campsis radicans) Control in Double-Crop Glyphosate-Resistant Soybean with Glyphosate and Conventional Herbicide Systems
Authors: Bradley Kevin W. , Hagood Edward S. , Davis Paul H.
Published: July 2006

Field trials were conducted in Virginia to evaluate trumpetcreeper control with glyphosate and conventional herbicide systems in double-crop glyphosate-resistant soybean. When compared with the untreated control, none of the conventional herbicide systems evaluated in these trials provided any reductions in the trumpetcreeper stem density at 1 yr after treatment (YAT). Glyphosate systems generally provided much higher levels of trumpetcreeper stem reduction than conventional herbicide systems. By 1 YAT, densities of trumpetcreeper that received conventional herbicide treatments ranged from 97 to 141% of the initial population, whereas densities of trumpetcreeper that received preemergence (PRE) followed by postemergence (POST) or POST-only applications of the isopropylamine (IPA) or diammonium (DIA) salts of glyphosate ranged from 30 to 66% of the initial population. However, PRE applications of the IPA or DIA salts of glyphosate generally provided lower levels of trumpetcreeper stem reduction than PRE followed by POST or POST-only applications. These results indicate that glyphosate applications made later in the growing season will provide greater trumpetcreeper stem reductions than those made at or close to soybean planting in double-crop soybean production systems. Glyphosate systems did not provide higher soybean yields than the untreated control that contained trumpetcreeper only when densities averaged 6 trumpetcreeper stems/m2in 2000, but 12 of the 16 glyphosate-containing treatments provided higher soybean yields than the untreated control that contained trumpetcreeper only when densities averaged 13 stems/m2in 2001.
Field Performance of Glyphosate as Influenced by Selected Adjuvants and a Low-Volume, Air-Assisted Sprayer
Authors: Faircloth Wilson H. , Patterson Michael G. , Belcher Sidney B. , Sanders Jason C. , Stephenson Daniel O.
Published: July 2006

Field studies were conducted at the Alabama Agricultural Experiment Station near Shorter, AL, from 1998 to 2000 to evaluate six commercial spray adjuvants and their effects on glyphosate applied to cotton with an air-assisted sprayer. Each adjuvant was evaluated with a conventional sprayer calibrated to deliver 94 L/ha solution and a low-volume, air-assisted sprayer calibrated to deliver 19 L/ha solution. Glyphosate was applied to two-leaf pitted and entireleaf morningglory growing in glyphosate-resistant cotton. Visual control of pitted and entireleaf morningglory was more dependent on the rate of herbicide application than on a particular adjuvant or sprayer, with glyphosate at 0.42 kg ae/ha providing 70% control 21 d after treatment. Pitted and entireleaf morningglory biomass measurements generally reflected visual control data. Ammonium sulfate and formulated glyphosate consistently gave the highest visual control and the greatest biomass reduction. Glyphosate application rate was more important than adjuvant addition or sprayer type, with the higher rates of application providing greater control. No differences in weed control were observed between spray systems; therefore, air-assisted sprayers may be used on a field-scale basis with consistent and adequate results.
Use of the Sulfonylurea-Tolerant Soybean Trait to Reduce Soybean Response to Prosulfuron Soil Residues
Authors: Anderson Adam H. , Simmons F. William
Published: July 2006

Field studies were conducted to examine the effects of the sulfonylurea-tolerant (ST) soybean and fall tillage on reducing rotational soybean response to soil-applied prosulfuron across a range of soil pH values. Prosulfuron (10 and 20 g ai/ha) was applied in the fall to simulate the maximum amount of carryover theoretically possible from corn weed control systems. ST soybean reduced effects of prosulfuron soil residues on soybean grain yield. Increased soil pH led to greater prosulfuron carryover as indicated by the differential in ST and non-ST soybean and grain yield responses. Tillage (chisel plow) did not decrease non-ST soybean response to prosulfuron soil residues. Soybean injury 30 d after emergence was well correlated with eventual yield losses in non-ST soybean. Greater soybean injury and yield loss was observed on a silt loam soil with 0.8% organic carbon than on silt loams with greater than 2.5% organic carbon.
Control of Volunteer Glyphosate-Resistant Cotton in Glyphosate-Resistant Soybean
Authors: York Alan C. , Stewart Alexander M. , Vidrine P. Roy , Culpepper A. Stanley
Published: July 2006

Cotton boll weevil has been eradicated from much of the U.S. Cotton Belt. After eradication, a containment program is necessary to detect and destroy reintroduced boll weevils. Crops other than cotton are not monitored for boll weevil, hence fruit on volunteer glyphosate-resistant (GR) cotton in GR soybean could provide oviposition sites for boll weevils and allow the insects to build up undetected. An experiment was conducted at five locations to evaluate control of GR cotton and reduction in cotton fruit production by herbicides commonly used on GR soybean. Cotton control by preemergence (PRE) or postemergence (POST) herbicides alone was inconsistent across locations. Flumetsulam at 45 g ai/ha, imazaquin at 137 g ai/ha, and metribuzin at 360 g ai/ha plus chlorimuron at 60 g ai/ha applied PRE controlled cotton 55 to 100% and reduced cotton fruit production 84 to 100%. Sulfentrazone at 167 g ai/ha plus chlorimuron at 34 g/ha PRE controlled cotton 50 to 91% and reduced fruit 48 to 98%. Metribuzin PRE at 420 g/ha controlled cotton 23 to 97% and reduced fruit 32 to 100%. Flumiclorac at 30 g ai/ha, 2,4-DB dimethylamine salt at 35 g ae/ha, chlorimuron at 12 g ai/ha, and the sodium salt of fomesafen at 420 g ai/ha mixed with glyphosate and applied POST controlled cotton 48 to 100% and reduced fruit production 67 to 100%. Cloransulam at 12 or 18 g ai/ha controlled cotton 3 to 66% and reduced fruit production 5 to 85%. Cotton control and fruit reduction were greatest and most consistent with sequential applications of metribuzin plus chlorimuron PRE followed by chlorimuron, flumiclorac, fomesafen, or 2,4-DB POST. These treatments controlled cotton at least 95% at all locations. Cotton fruit was totally eliminated at three locations and reduced at least 97% at a fourth location.
In-Season Applications of Glyphosate for Control of Redvine (Brunnichia ovata) in Glyphosate-Resistant Soybean
Authors: Akin D. Scott , Shaw David R.
Published: July 2006

An experiment was initiated at two sites in 1998 near Crowder, MS, to evaluate the effect of in-season applications of glyphosate on redvine populations in glyphosate-resistant soybean. In the year of application, most treatments containing multiple in-season applications of glyphosate reduced redvine populations. However, at 16 mo after treatment (October 1999), 0.63 kg ai/ha paraquat preplant followed by sequential postemergence applications of glyphosate at 1.1 and 2.2 kg ai/ ha reduced redvine stems by 45% compared with the untreated check. Redvine control with this treatment also was comparable with 2.2 kg ai/ha dicamba preharvest. The same results were observed at 12 and 14 mo after application with many treatments containing sequential applications of glyphosate, but glyphosate at 1.1 and 2.2 kg ai/ha was the only in-season treatment to maintain redvine suppression during the entire growing season the year after herbicide application. However, a number of treatments delayed redvine reinfestation; thus, soybean yield was improved over the untreated check with all treatments from the previous year containing in-season applications of glyphosate, except for 0.84 kg/ha followed by 0.56 kg/ha. Increasing rates of in-season glyphosate applications to 1.1 followed by 2.2 kg/ha will adequately suppress redvine populations in glyphosate-resistant soybean, controlling annual weeds in the process.
Sulfentrazone Persistence in Southern Soils: Bioavailable Concentration and Effect on a Rotational Cotton Crop
Authors: Main Christopher L. , Mueller Thomas C. , Hayes Robert M. , Wilcut John W. , Peeper Thomas F. , Talbert Ronald E. , Witt William W.
Published: July 2006

Field studies were conducted from 1998 to 2000 in Tennessee, North Carolina, Arkansas, and Oklahoma to determine the effects of sulfentrazone carryover to a cotton rotational crop from sulfentrazone applied the previous year. Sulfentrazone applied the previous year at 400 g/ha caused no yield loss in Tennessee, >30% yield reduction in Oklahoma, and 20% yield loss in Arkansas and North Carolina. In most experiments in this study, visual evaluations of injury closely correlated with final cotton lint yield (r2=0.84).
Response of Selected Grass and Broadleaf Species to Cogongrass (Imperata cylindrica) Residues
Authors: Koger Clifford H. , Bryson Charles T. , Byrd John D.
Published: July 2006

Effects of cogongrass foliage and rhizome plus root residues on germination and shoot and root growth of barnyardgrass, bermudagrass, browntop millet, hemp sesbania, Italian ryegrass, and prickly sida were investigated in greenhouse experiments. Ground residues of dried cogongrass foliage and rhizomes plus roots were mixed separately with sterilized sand to obtain residue concentrations of 0, 0.25, 0.5, 1, 2, 4, and 8%. These residue concentrations were investigated on bermudagrass and Italian ryegrass, and the 8% residue concentrations were also evaluated on hemp sesbania, prickly sida, barnyardgrass, and browntop millet. Foliage and rhizome plus root residues at concentrations as low as 0.25% inhibited seed germination and shoot and root growth of all species except hemp sesbania. Germination of bermudagrass and Italian ryegrass was reduced by as much as 97% and shoot and root growth by as much as 94% at the highest residue concentrations. Rhizome plus root residues reduced germination and shoot and root growth of bermudagrass and Italian ryegrass more than foliage residues. Foliage and rhizome plus root residues reduced germination and shoot and root biomass of prickly sida, barnyardgrass, and browntop millet at similar levels. Results indicate that cogongrass tissue may contain allelochemicals that contribute to its invasiveness and extreme competitiveness.
Remote Sensing to Distinguish Soybean from Weeds After Herbicide Application
Authors: Henry W. Brien , Shaw David R. , Reddy Kambham R. , Bruce Lori M. , Tamhankar Hrishikesh D.
Published: July 2006

Two experiments, one focusing on preemergence (PRE) herbicides and the other on postemergence (POST) herbicides, were conducted and repeated in time to examine the utility of hyperspectral remote sensing data for discriminating common cocklebur, hemp sesbania, pitted morningglory, sicklepod, and soybean after PRE and POST herbicide application. Discriminant models were created from combinations of multiple indices. The model created from the second experimental run's data set and validated on the first experimental run's data provided an average of 97% correct classification of soybean and an overall average classification accuracy of 65% for all species. These data suggest that these models are relatively robust and could potentially be used across a wide range of herbicide applications in field scenarios. From the data set pooled across time and experiment types, a single discriminant model was created with multiple indices that discriminated soybean from weeds 88%, on average, regardless of herbicide, rate, or species. Signature amplitudes, an additional classification technique, produced variable results with respect to discriminating soybean from weeds after herbicide application and discriminating between controls and plants to which herbicides were applied; thus, this was not an adequate classification technique.
Biennial Wormwood (Artemisia biennis) Early-Season Control with Herbicides
Authors: Fronning Bradley E. , Kegode George O.
Published: July 2006

Biennial wormwood has become a problem for soybean producers in the northern Great Plains of the United States. Research was conducted to evaluate control of biennial wormwood with preemergence (PRE) herbicides alone or followed by postemergence (POST) herbicides in 2000 and 2001 at Fargo, Leonard, and Wyndmere, ND. Favorable soil moisture conditions at Leonard resulted in continual emergence and greater densities of biennial wormwood, whereas the soil at Fargo and Wyndmere was dry and few biennial wormwood seedlings emerged at these locations. Biennial wormwood control with PRE herbicides was greater than 89% at Fargo and Wyndmere but was 80% or lower at Leonard. PRE biennial wormwood control was higher with flumetsulam than with sulfentrazone. When POST treatments were applied after PRE herbicides, biennial wormwood control 4 wk after treatment was 92% or better at Fargo and Wyndmere but was 76% or less at Leonard. The combination of PRE and POST herbicide treatments did not improve control greatly at Fargo or Wyndmere but at Leonard reduced the number of biennial wormwood plants.
Influence of Sulfentrazone Rate and Application Method on Peanut Weed Control
Authors: Grey Timothy L. , Bridges David C. , Hancock H. Gary , Davis Jerry W.
Published: July 2006

Field studies were conducted in 2000 and 2001 in Plains, GA, to determine peanut and weed response to the residual herbicides sulfentrazone, imazapic, diclosulam, and flumioxazin. Herbicide treatments included sulfentrazone applied preemergence (PRE) or preplant incorporated (PPI) at 112, 168, 224, and 280 g ai/ha, imazapic postemergence (POST) at 71 g ai/ha, diclosulam PPI at 26 g ai/ha, and flumioxazin PRE at 88 g ai/ha. Peanut exhibited early-season injury from all herbicide treatments, ranging from 0 to 10% for sulfentrazone PPI or PRE, 10% for imazapic, 3 to 23% for flumioxazin, and 1 to 7% for diclosulam. Yields were similar for sulfentrazone PPI- or PRE-treated and flumioxazin-, imazapic-, and diclosulam-treated peanut. Yellow nutsedge control was 83% or greater with all rates of sulfentrazone PRE or PPI, 83 and 90% with diclosulam, and 96 and 99% with imazapic, respectively. Flumioxazin did not control yellow nutsedge or wild poinsettia. Tall morningglory control was 82% or greater with imazapic, diclosulam, flumioxazin, and sulfentrazone PPI or PRE at 168 g/ha or higher. Florida beggarweed control was 88% or greater with diclosulam, flumioxazin, and sulfentrazone PRE at 224 and 280 g/ha. Overall, peanut tolerance to sulfentrazone at 112 to 280 g/ha PPI and PRE was high and yield was equivalent to the currently registered peanut residual herbicides.
Quinclorac: Soil Behavior and Foliar vs. Root Absorption by Torpedograss (Panicum repens)
Authors: Williams Walker , Wehtje Glenn , Walker Robert H.
Published: July 2006

Selective placement studies were conducted under greenhouse conditions to determine the relative importance of root vs. foliar absorption of postemergence-applied quinclorac by torpedograss. Foliar + soil and soil-only applications were more effective than foliar-only in reducing torpedograss foliage at 4 wk after treatment (WAT). However, foliar-only and foliar + soil were more effective than soil-only in suppressing regrowth at 10 WAT. Quinclorac foliar absorption by torpedograss and subsequent translocation, as determined with radiotracer techniques, was minimal. After 72 h, only 26% of the applied quinclorac had been absorbed, and 13.7% of the amount applied remained within the treated leaf. Only 0.3% of applied was recovered in the roots, and none was detected in the developing rhizomes. Quinclorac was readily root absorbed and translocated. After 6 h, a 26.7 μg/plant dose of quinclorac had been absorbed, and 54% of this quantity remained in the roots; the remaining 46% having been translocated throughout the plant. The youngest leaf and the immature rhizomes accumulated 5 and 9% of the amount absorbed, respectively. Quinclorac was not readily soil sorbed as determined by soil solution experiments. Quinclorac was displaced nearly concomitant with the wetting front in soil chromatography. Soil solution concentration and soil mobility were greater at pH 6.7 than at 5.7. Results establish that consistent control of torpedograss with quinclorac is dependent on soil entry and root absorption. Unfortunately, the propensity of quinclorac to be water displaced could negatively affect this control.
Goosegrass (Eleusine indica) Control with Foramsulfuron in Bermudagrass (Cynodonspp.) Turf
Authors: Busey Philip
Published: July 2006

Field studies were conducted to evaluate foramsulfuron for postemergence control of goosegrass in bermudagrass turf as a possible replacement for MSMA. In field trials on a golf course and sports fields planted to bermudagrass, mature goosegrass was controlled effectively (>85% goosegrass dead on the basis of canopy area) with two applications of foramsulfuron plus metribuzin. The herbicide rates that were effective varied among studies, e.g., foramsulfuron at 0.029 or 0.044 kg ai/ha mixed with metribuzin at 0.105 to 0.210 kg ai/ha. Goosegrass was often controlled with MSMA at 2.24 kg ai/ha plus metribuzin at 0.105 to 0.210 kg/ha, but foramsulfuron was always as effective, or more effective, than MSMA, in controlling mature goosegrass, at the same rate of metribuzin. Bermudagrass phytotoxicity of foramsulfuron plus metribuzin was temporary and not different from MSMA plus metribuzin. In one location there was noticeable phytotoxicity 4 wk after initial treatment.
Establishment of Seeded Centipedegrass (Eremochloa ophiuroides) in Utility Turf Areas
Authors: Gannon Travis W. , Yelverton Fred H. , Cummings Hennen D. , McElroy J. Scott
Published: July 2006

Experiments were conducted to evaluate safety and effectiveness of herbicides during establishment of seeded centipedegrass. Centipedegrass tolerance to herbicides was evaluated at seeding and early postemergence. Imazapic at 105 g ai/ha, sulfometuron at 53 g ai/ha, or metsulfuron at 21 or 42 g ai/ha applied at seeding reduced centipedegrass ground cover compared with the nontreated. Imazapic at 18 or 35 g/ha or applications of atrazine or simazine at seeding did not reduce centipedegrass ground cover compared with the nontreated. Applications of chlorsulfuron plus mefluidide (7 + 140 g ai/ha) or metsulfuron at 21 or 42 g/ha applied 6 wk after seeding (WAS) centipedegrass (one-leaf to one-tiller growth stage) caused 20, 16, and 83% phytotoxicity, respectively, 56 d after treatment (DAT). Imazapic, sulfometuron, atrazine, or simazine applied 6 WAS caused <15% phytotoxicity 56 DAT. When large crabgrass and centipedegrass were seeded together, large crabgrass emergence was reduced 41% when atrazine (1,100 g ai/ha) was applied at seeding. Centipedegrass tiller production was reduced with increasing amounts of crabgrass. However, centipedegrass tiller production and ground cover were higher when atrazine was applied because of reduced interspecific interference from large crabgrass. These data indicate that centipedegrass can be established more quickly if appropriate herbicides are used at seeding or shortly after seeding.