Response of Monocot and Dicot Weed Species to Fresnel Lens Concentrated Solar Radiation

Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 797-801 ◽  
Author(s):  
David W. Johnson ◽  
James M. Krall ◽  
Ronald H. Delaney ◽  
Larry O. Pochop
Keyword(s):  
Solar Radiation ◽  
Field Experiments ◽  
Focal Length ◽  
Soil Surface ◽  
Fresnel Lens ◽  
Weed Species ◽  
Concentrate Solar Radiation ◽  
Redroot Pigweed ◽  
Concentrated Solar Radiation ◽  
Dry Soil

Fresnel lenses are used to concentrate solar radiation to a line or point. A linear Fresnel lens (0.91 by 1.52 m, 0.74-m focal length, 0.01- by 1.52-m line focus) was investigated as a method for weed control. Field experiments were conducted to assess the effect of Fresnel lens concentrated solar radiation at various exposure times, stages of plant growth, and soil surface moisture conditions. On a dry soil surface exposure times of 1 to 10 s at 290 C resulted in control of redroot pigweed from 100% for a 1-s exposure at the cotyledon stage to 89% for a 10-s exposure at the 10-leaf stage. Redroot pigweed and kochia control was similar at exposures of 3 to 10 s, but less for kochia at 1 and 2 s. Green foxtail control was less than that of kochia and redroot pigweed. Control was reduced on a moist compared to a dry soil surface. Concentrated solar radiation holds the greatest potential for control of small dicot weeds on a dry soil surface.

Response of Seed of 10 Weed Species to Fresnel-lens-concentrated Solar Radiation

1990 ◽  
Vol 4 (1) ◽  
pp. 109-114 ◽  
Author(s):  
David W. Johnson ◽  
James M. Krall ◽  
Ronald H. Delaney ◽  
David S. Thiel
Keyword(s):  
Solar Radiation ◽  
Soil Depth ◽  
Soil Surface ◽  
Fresnel Lens ◽  
Weed Seed ◽  
Weed Species ◽  
Green Foxtail ◽  
Fresnel Lenses ◽  
Concentrated Solar Radiation ◽  
Common Purslane

A curved-linear Fresnel lens was investigated to test the effect of concentrated solar radiation on surface and buried weed seed. The lens produced a line focus 1 by 150 cm with a mean temperature of 309 C. A 20-s exposure to seed on the soil surface was 100% lethal to green foxtail, kochia, common lambsquarters, common purslane, and wild buckwheat. In a separate study, emergence from kochia and yellow foxtail seed was reduced 100% at 10 mm soil depth after 15 min in soil of 35 and 93 g/kg moisture and 20 to 40% at 178 g/kg moisture content. Concentrated solar radiation from a Fresnel lens has the greatest potential for affecting weed seed on the soil surface. A series of Fresnel lenses and/or larger lenses may be required for many practical field applications.

Dissipation and Water Activation of UCC-C4243

Weed Science ◽  
1995 ◽  
Vol 43 (1) ◽  
pp. 149-155 ◽  
Author(s):  
Terry R. Wright ◽  
Alex G. Ogg ◽  
E. Patrick Fuerst
Keyword(s):  
Field Experiments ◽  
Soil Surface ◽  
Simulated Rainfall ◽  
Herbicide Application ◽  
Weed Species ◽  
Natural Rainfall ◽  
Near Ultraviolet ◽  
Glass Slides ◽  
Water Activation ◽  
Herbicide Activity

Field experiments were conducted in 1992 and 1993 to determine the timing and amount of rainfall required to activate UCC-C4243 applied preemergence. UCC-C4243 at 0, 70, and 140 g ai ha−1was applied 1, 7, 14, and 21 d before 0.5 or 2 cm of simulated rainfall. Temporary rainshelters protected field plots from natural rainfall during the 21 d dry period. Herbicide activity was determined in the field by seeding lentil, wheat, common lambsquarters, and field pennycress and in the greenhouse by a sugarbeet bioassay of soil samples (0 to 3 cm depth) taken from all plots immediately before irrigation. UCC-C4243 did not injure wheat; however, lentil population was reduced when simulated rainfall occurred within 7 d after application. Lentil injury was greater with higher herbicide rate and higher water level. UCC-C4243 at 70 and 140 g ha−1reduced populations of both weed species by 75 and 90%, respectively, when either 0.5 or 2 cm simulated rainfall was received within 1 d after herbicide application. Weed control was reduced with a 21 d delay between herbicide application and water activation. The sugarbeet bioassay showed a linear decrease of herbicide activity over time and also with accumulated photosynthetically active radiation. After 17.9 d, herbicide activity on a dry soil surface decreased 50%. Laboratory investigations show that [14C]-UCC-C4243 on glass slides was photodegraded by near ultraviolet light (290 to 400 nm). Volatilization of14C-labeled herbicide from glass slides was less than 5% after exposure to turbulent air for 48 h.

Seed bank characterization and emergence of a weed community in a moldboard plow system

Weed Science ◽  
1997 ◽  
Vol 45 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Dawit Mulugeta ◽  
David E. Stoltenberg
Keyword(s):  
Seed Bank ◽  
Field Experiments ◽  
Negative Binomial ◽  
Soil Disturbance ◽  
Weed Seed ◽  
Weed Species ◽  
Common Lambsquarters ◽  
Redroot Pigweed ◽  
Viable Seeds ◽  
Moldboard Plow

Field experiments were conducted in 1992 and 1993 to characterize the weed seed bank, to determine the influence of moldboard plowing and secondary soil disturbance on the emergence pattern of weeds, and to measure weed seed bank depletion by emergence in a long-term moldboard plow corn cropping system. Viable seeds of common lambsquarters, redroot pigweed, and each of 10 other species accounted for about 85, about 9, and less than 1%, respectively, of the total weed species in the seed bank. A negative binomial distribution described the spatial distribution of viable seeds of 10 species, but not of common lambsquarters or of redroot pigweed. Decreased density of seeds among species was associated with increased aggregation. Secondary soil disturbance increased the rate and magnitude of common lambs quarters emergence in 1992 but did not influence emergence in 1993. Secondary soil disturbance did not influence the magnitude and rate of emergence of redroot pigweed or velvetleaf. Whereas cumulative growing degree days from April through July were similar between years, the amount of rainfall was about 50% less in 1992 than in 1993. Secondary soil disturbance may have increased common lambsquarters emergence by increasing the availability of soil moisture and improving conditions for seed germination during the dry year. Even though seed bank depletion by seedling emergence was relatively low for all species, secondary soil disturbance in creased seed bank depletion of common lambsquarters and redroot pigweed about 7- and 3-fold, respectively, in 1992. Seasonal variation in the amount of rainfall may have influenced the effect of soil disturbance on emergence and seed bank depletion of common lambsquarters, which is the most abundant species in the weed community.

Growth Stage-Influenced Differential Response of Foxtail and Pigweed Species to Broadcast Flaming

2010 ◽  
Vol 24 (3) ◽  
pp. 319-325 ◽  
Author(s):  
Santiago M. Ulloa ◽  
Avishek Datta ◽  
Stevan Z. Knezevic
Keyword(s):  
Weed Control ◽  
Dry Matter ◽  
Growth Stage ◽  
Field Experiments ◽  
Growth Stages ◽  
Weed Species ◽  
Common Waterhemp ◽  
Species Response ◽  
Redroot Pigweed ◽  
Green Foxtail

Propane flaming could be an effective alternative tool for weed control in organic cropping systems. However, response of major weeds to broadcast flaming must be determined to optimize its proper use. Therefore, field experiments were conducted at the Haskell Agricultural Laboratory, Concord, NE in 2007 and 2008 using six propane doses and four weed species, including green foxtail, yellow foxtail, redroot pigweed, and common waterhemp. Our objective was to describe dose–response curves for weed control with propane. Propane flaming response was evaluated at three different growth stages for each weed species. The propane doses were 0, 12, 31, 50, 68, and 87 kg ha−1. Flaming treatments were applied utilizing a custom-built flamer mounted on a four-wheeler (all-terrain vehicle) moving at a constant speed of 6.4 km h−1. The response of the weed species to propane flaming was evaluated in terms of visual ratings of weed control and dry matter recorded at 14 d after treatment. Weed species response to propane doses were described by log-logistic models relating propane dose to visual ratings or plant dry matter. Overall, response of the weed species to propane flaming varied among species, growth stages, and propane dose. In general, foxtail species were more tolerant than pigweed species. For example, about 85 and 86 kg ha−1were the calculated doses needed for 90% dry matter reduction in five-leaf green foxtail and four-leaf yellow foxtail compared with significantly lower doses of 68 and 46 kg ha−1of propane for five-leaf redroot pigweed and common waterhemp, respectively. About 90% dry matter reduction in pigweed species was achieved with propane dose ranging from 40 to 80 kg ha−1, depending on the growth stage when flaming was conducted. A similar dose of 40 to 60 kg ha−1provided 80% reduction in dry matter for both foxtail species when flaming was done at their vegetative growth stage. However, none of the doses we tested could provide 90% dry matter reduction in foxtail species at flowering stage. It is important to note that foxtail species started regrowing 2 to 3 wk after flaming. Broadcast flaming has potential for control or suppression of weeds in organic farming.

Processing Tomato and Weed Response to Flufenacet plus Metribuzin

2004 ◽  
Vol 18 (3) ◽  
pp. 801-809 ◽  
Author(s):  
Peter H. Sikkema ◽  
Allan S. Hamill ◽  
Mirwais M. Qaderi ◽  
Colleen Doucet
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Weed Species ◽  
Early Season ◽  
Commercial Formulation ◽  
Common Lambsquarters ◽  
Processing Tomato ◽  
Redroot Pigweed ◽  
Application Rates ◽  
Green Foxtail

Field experiments were conducted in 1998, 1999, and 2000 at two locations (Harrow and Ridgetown) in southwestern Ontario to determine the biologically effective rates (I90) of a commercial formulation of flufenacet plus metribuzin for weed control and processing tomato tolerance. At the proposed label use rate, flufenacet plus metribuzin provided excellent (≥90%) early-season (22 to 29 d after planting) control of velvetleaf, good (80 to 89%) control of barnyardgrass and redroot pigweed, and fair (60 to 79%) control of common lambsquarters. Flufenacet plus metribuzin provided fair late-season (59 to 97 d after planting) control of redroot pigweed and common lambsquarters and poor (≤59%) control of barnyardgrass and velvetleaf. At Harrow and Ridgetown, I90values for early-season weed control ranged from 70 to 1,300 g ai/ha and 50 to 1,900 g ai/ha, respectively. Flufenacet plus metribuzin provided poor weed control at Ridgetown. This result was not attributable to higher weed density or particular weed species but may have been caused by lack of rainfall and too low application rates for the medium-textured soil type. It is estimated that flufenacet plus metribuzin at 1,400 g/ha can control green foxtail season-long, whereas barnyardgrass and common lambsquarters would require 1,900 g/ha. Season-long control of velvetleaf and redroot pigweed would require application rates of 3,200 and 7,100 g/ha, respectively. Only slight early-season crop injury was observed, which was not reflected in yields. Optimum yields of tomatoes were obtained at Harrow at rates lower or slightly higher than the registered rates for corn and soybean. Tomato yields were higher at Harrow than at Ridgetown, which may have been due to differences in soil texture. Tomatoes grown in a medium-textured (Ridgetown) soil appeared to be less competitive against weeds than those grown in a coarse-textured soil (Harrow).

Selectivity of Pyriclor on Witchweed, Tobacco, and Other Plants

Weed Science ◽  
1971 ◽  
Vol 19 (1) ◽  
pp. 90-93
Author(s):  
Jim E. Dale
Keyword(s):  
Acetic Acid ◽  
Solanum Tuberosum ◽  
Field Experiments ◽  
Soil Surface ◽  
Irish Potato ◽  
Weed Species ◽  
Digitaria Sanguinalis ◽  
Crop Species ◽  
Dichlorophenoxy Acetic Acid ◽  
Over The Top

Postemergence directed application of 0.56 kg/ha of 2,3,5-trichloro-4-pyridinol (pyriclor) gave control of witchweed (Striga lutea Lour.) equivalent to 2.24 kg/ha of (2,4-dichlorophenoxy)acetic acid (2,4-D) without injuring corn (Zea mays L.). Pyriclor applied to the soil surface or incorporated did not significantly injure tobacco (Nicotiana tabacum L.) at rates of 2.24 kg/ha and less. Peanut (Arachis hypogaea L.) was not injured by pyriclor incorporated in soil at 0.56 kg/ha; Irish potato (Solanum tuberosum L.) was slightly injured. Treatment with 0.56 kg/ha of pyriclor applied in the same manner killed six crop species and four weed species also included in the experiment. In 2 years of field experiments, application of pyriclor at 0.21 and 0.63 kg/ha to soil before transplanting, or these rates applied over the top of tobacco after transplanting, controlled large crabgrass (Digitaria sanguinalis L. Scop.) until maturity of the tobacco, and did not significantly reduce yield or cause permanent injury to the crop.

Single and Sequential Applications of Tribenuron on Broadleaf Weed Control and Crop Response in Tribenuron-Resistant Sunflower

2011 ◽  
Vol 25 (3) ◽  
pp. 391-397 ◽  
Author(s):  
Amar S. Godar ◽  
Phillip W. Stahlman ◽  
J. Anita Dille
Keyword(s):  
Weed Control ◽  
Seed Oil ◽  
Field Experiments ◽  
Acetolactate Synthase ◽  
Crop Response ◽  
Weed Species ◽  
Redroot Pigweed ◽  
Crop Injury ◽  
Significant Yield ◽  
Significant Injury

Field experiments were conducted near Hays, KS in 2007 and 2008 to evaluate the effects of single and sequential postemergent applications of tribenuron on broadleaf weed control and crop response in tribenuron-resistant sunflower. Weeds were acetolactate-synthase–susceptible biotypes of kochia, puncturevine, Russian thistle, and tumble pigweed in 2007 and puncturevine, redroot pigweed, and tumble pigweed in 2008. Tribenuron at 18 g ai ha−1applied early POST with methylated seed oil (MSO) provided > 96% control of all species in 2007 and 92 and 99% control of redroot pigweed and puncturevine, respectively, but only 69% control of tumble pigweed in 2008. Early-POST tribenuron at 9 g ha−1and late-POST tribenuron at 18 g ha−1generally provided less weed control compared to early-POST tribenuron at 18 g ha−1. Sequential applications slightly improved redroot pigweed and tumble pigweed control in 2008 compared to single applications of tribenuron. Some tribenuron treatments caused transitory crop injury, but imazamox at 35 g ha−1caused 24 to 44% crop injury at 7 d after treatment and permanent crop stunting in 2007. Significant yield losses occurred with imazamox and single treatments of tribenuron in 2008. Collectively, tribenuron at 18 g ha−1alone can provide satisfactory control of the evaluated broadleaf weed species when applied to appropriate weed sizes, and this rate does not cause significant injury to tribenuron-resistant sunflower, regardless of the crop size.

Feeding Preferences of Weed Seed Predators and Effect on Weed Emergence

Weed Science ◽  
2007 ◽  
Vol 55 (6) ◽  
pp. 606-612 ◽  
Author(s):  
Sharon S. White ◽  
Karen A. Renner ◽  
Fabian D. Menalled ◽  
Douglas A. Landis
Keyword(s):  
Common Ground ◽  
Field Experiments ◽  
Field Cricket ◽  
Feeding Preferences ◽  
Weed Species ◽  
Seed Predators ◽  
Redroot Pigweed ◽  
Greenhouse Study ◽  
Giant Foxtail ◽  
Weed Emergence

We determined feeding preferences of invertebrate seed predators and the effect of seed predation on weed emergence. Feeding choice studies were completed with three species of common ground beetles: (Amara aeneaDeGeer,Anisodactylus sanctaecrucisF., andHarpalus pensylvanicusDeGeer) (Coleoptera: Carabidae) and the northern field cricket (Gryllus pennsylvanicusDeGeer) (Orthoptera: Gryllidae).Anisodactylus sanctaecrucis,H. pensylvanicus, and the female and maleG. pennsylvanicusconsumed more redroot pigweed seeds compared with giant foxtail seeds;A. aeneaseed consumption did not differ between these two weed species. All invertebrates consumed fewer velvetleaf seeds compared with redroot pigweed and giant foxtail seeds; however, when seed biomass was compared,A. aeneaconsumed similar biomass of velvetleaf, giant foxtail, and redroot pigweed, whereasA. sanctaecrucisandH. pensylvanicusconsumed greater biomass of velvetleaf compared with giant foxtail seed. Seed burial depths of 0.5 or 1.0 cm reduced redroot pigweed and giant foxtail seed consumption byA. aeneaandA. sanctaecrucisbut not by the larger carabid beetle,H. pensylvanicus. In a greenhouse study,A. sanctaecrucisdecreased total weed emergence by 15%, andG. pennsylvanicusfemales and males decreased weed emergence by 16 and 5%, respectively. Emergence of redroot pigweed, but not velvetleaf or giant foxtail, decreased whenA. sanctaecrucisand the maleG. pennsylvanicuswere present, whereas the emergence of all three weed species decreased in the presence of the femaleG. pennsylvanicus. In field experiments, vertebrate access to velvetleaf seeds reduced emergence from 4 to 9% across field sites; invertebrate access reduced emergence 4 to 6%. Vertebrate access to giant foxtail seeds reduced emergence 3 to 7%, and invertebrate access reduced emergence 4 to 13%. These results suggest that predation of weed seeds by both vertebrates and invertebrates may reduce weed emergence and influence the weed community.

Weed Control and Crop Safety with Premixed Pyrasulfotole and Bromoxynil in Grain Sorghum

2013 ◽  
Vol 27 (4) ◽  
pp. 664-670 ◽  
Author(s):  
Seshadri S. Reddy ◽  
Phillip W. Stahlman ◽  
Patrick W. Geier ◽  
Curtis R. Thompson ◽  
Randall S. Currie ◽  
...  
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Grain Sorghum ◽  
Palmer Amaranth ◽  
Crop Response ◽  
Weed Species ◽  
Grain Yields ◽  
Common Lambsquarters ◽  
Redroot Pigweed

Field experiments were conducted in grain sorghum at five locations in Kansas in 2009 and 2010, to evaluate the efficacy and crop safety of early- to mid-POST (EMPOST) and late-POST (LPOST) applications of premixed pyrasulfotole and bromoxynil (PYRA&BROM) in tank mix combinations with atrazine or atrazine plus 2,4-D ester or dicamba compared to bromoxynil plus atrazine. PYRA&BROM at 244 or 300 g ai ha−1 plus atrazine at 560 g ai ha−1 applied EMPOST controlled pigweed species (Palmer amaranth, tumble pigweed, and redroot pigweed), kochia, velvetleaf, common sunflower, ivyleaf morningglory, and common lambsquarters 93% or greater. Puncturevine control among three locations ranged from 85 to 99%. Control of most weed species was not improved by increasing PYRA&BROM rate from 244 to 300 g ha−1 or by tank mixing 2,4-D or dicamba with PYRA&BROM plus atrazine. However, ivyleaf morningglory control was improved at the LPOST timing by adding 2,4-D or dicamba at 140 g ae ha−1. In no instance did any PYRA&BROM treatment provide greater weed control than bromoxynil plus atrazine at 281 + 560 g ha−1 when applied EMPOST, but in most instances PYRA&BROM treatments were more effective than bromoxynil plus atrazine when applied LPOST. Generally, PYRA&BROM treatments were more effective when applied EMPOST than LPOST, especially when 2,4-D or dicamba was added. PYRA&BROM plus atrazine treatments caused foliar bleaching in sorghum within 7 ± 3 d after treatment, but recovery was complete within 3 to 4 wk and grain yields were not reduced. Tank mixing dicamba with PYRA&BROM and atrazine occasionally reduced visible crop response compared to PYRA&BROM plus atrazine. Our results indicate that PYRA&BROM plus atrazine with or without 2,4-D or dicamba selectively controls several troublesome broadleaf weeds in grain sorghum. Foliar bleaching of sorghum leaves can occur but the symptoms are transient, and grain yields are not likely to be reduced.

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