Canopy and Chemistry of Pasture Weeds

Weed Science ◽  
1980 ◽  
Vol 28 (2) ◽  
pp. 139-141 ◽  
Author(s):  
R. J. Carlisle ◽  
V. H. Watson ◽  
A. W. Cole
Keyword(s):  
Crude Protein ◽  
Warm Season ◽  
Leaf Size ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Chemical Characteristics ◽  
Solidago Altissima ◽  
Weed Species ◽  
Total Leaf Area ◽  
Ruminant Animals

Morphological and chemical characteristics of 11 warm season pasture weed species were defined. Goldenrod (Solidago altissima L.) was significantly taller and common ragweed (Ambrosia artemisiifolia L.) had the largest canopy diameter of the 11 species studied. Species ranged from 14 to 134 cm in height with canopy diameters of 25 to 70 cm. No direct correlation was found between individual leaf size and total leaf area. Macro- and micromineral content varied widely among species but all values obtained were considered high enough to meet the requirements of ruminant animals. Redroot pigweed (Amaranthus retroflexus L.) and horsenettle (Solanum carolinense L.) contained potentially toxic levels of nitrate. Five of the 11 species contained sufficient crude protein for ruminants and six of the 11 species were more than 50% digestible. Digestible energy values averaged 1.9 Mcal/kg for the 11 weeds evaluated.

Response of Weeds to Soil pH

Weed Science ◽  
1975 ◽  
Vol 23 (6) ◽  
pp. 473-477 ◽  
Author(s):  
G. A. Buchanan ◽  
C. S. Hoveland ◽  
M. C. Harris
Keyword(s):  
Soil Ph ◽  
Sandy Loam ◽  
Plantago Lanceolata ◽  
Warm Season ◽  
Amaranthus Retroflexus ◽  
Low Ph ◽  
Sandy Loam Soil ◽  
Weed Species ◽  
Stellaria Media ◽  
Loam Soil

Ten warm-season and six cool-season weed species were grown in the glasshouse on Hartsells fine sandy loam soil and Lucedale sandy loam soil at pH levels from 4.7 to 6.3. Growth of species varied widely in response to soil pH as measured by herbage yield. Showy crotalaria (Crotalaria spectabilis Roth), coffee senna (Cassia occidentalis L.), and large crabgrass (Digitaria sanguinalis (L.) Scop.] were highly tolerant to low pH soils. Sicklepod (Cassia obtusifolia L.), annual bluegrass (Poa annua L.), Carolina geranium (Geranium carolinianum L.), and buckhorn plantain (Plantago lanceolata L.), were medium to high in tolerance. Jimsonweed (Datura stramonium L.), tall morningglory [Ipomoea purpurea (L.) Roth], crowfootgrass [Dactyloctenium aegyptium (L.) Richter], and prickly sida (Sida spinosa L.) were medium to low in tolerance to low soil pH. Growth of Florida beggarweed [Desmodium tortuosum (Sw.) DC], redroot pigweed (Amaranthus retroflexus L.), chickweed [Stellaria media (L.) Cyrillo], common dandelion (Taraxacum officinale (Weber), and wild mustard [Brassica kaber (DC.) L.C. Wheeler var. pinnatifida (Stokes) L.C. Wheeler] was severely reduced in soils with low pH.

scholarly journals Weed Management in Transplanted Bell Pepper (Capsicum annuum) with Pretransplant Tank Mixes of Sulfentrazone, S-metolachlor, and Dimethenamid-p

HortScience ◽  
2008 ◽  
Vol 43 (5) ◽  
pp. 1492-1494 ◽  
Author(s):  
Darren E. Robinson ◽  
Kristen McNaughton ◽  
Nader Soltani
Keyword(s):  
Weed Management ◽  
Chenopodium Album ◽  
Fruit Size ◽  
Field Trials ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Bell Pepper ◽  
Weed Species ◽  
Marketable Yield ◽  
Excellent Control

Pepper growers currently have limited access to many effective broadleaf herbicides. Field trials were conducted over a 3-year period in Ontario to study the effect of tank mixtures of sulfentrazone (100 or 200 g·ha−1 a.i.) with either s-metolachlor (1200 or 2400 g·ha−1 a.i.) or dimethenamid-p (750 or 1500 g·ha−1 a.i.) on transplanted bell pepper. Under weed-free conditions, there was no visual injury or reduction in plant height, fruit number, fruit size, or marketable yield of transplanted pepper with pretransplant applications of sulfentrazone applied in tank mixtures with s-metolachlor or dimethenamid-p. The tank mixture of sulfentrazone + s-metolachlor gave greater than 85% control of redroot pigweed (Amaranthus retroflexus) and eastern black nightshade (Solanum ptycanthum), but only 70% to 76% control of velvetleaf (Abutilon theophrasti), common ragweed (Ambrosia artemisiifolia), and common lambsquarters (Chenopodium album). The combination of sulfentrazone + dimethenamid-p provided good to excellent control of all weed species except velvetleaf. Based on this study, sulfentrazone and dimethenamid-p have potential for minor use registration in pepper.

Utility of Maintained Weed Infestations Under Field Conditions

Weed Science ◽  
1970 ◽  
Vol 18 (2) ◽  
pp. 206-214 ◽  
Author(s):  
R. P. Upchurch ◽  
F. L. Selman ◽  
H. L. Webster
Keyword(s):  
Chenopodium Album ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Field Conditions ◽  
Moderate Degree ◽  
Weed Species ◽  
Common Ragweed ◽  
Common Lambsquarters ◽  
Dimethyl Urea ◽  
Polygonum Pensylvanicum

Relatively pure stands of eight weed species were maintained under field conditions on a Goldsboro loamy sand at Lewiston, North Carolina, for all or part of a 6-year period. Herbicides evaluated as preemergence surface treatments for these species were 2-sec-butyl-4,6-dinitrophenol (dinoseb), isopropyl m-chlorocarbanilate (chloropropham), 3-(3,4-dichlorophenyl)-1,1-dimethyl-urea (diuron), 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine), and 3-amino-2,5-dichlorobenzoic acid (amiben). S-ethyl dipropylthiocarbamate (EPTC) and a,a,a-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) were evaluated as preemergence incorporated treatments. The first four herbicides were evaluated in 1961, 1964, and 1966 while the last three were evaluated in 1962, 1963, and 1965. A series of rates was used for each chemical with three replications. With the exception of diuron which failed to control goosegrass (Eleusine indica (L.) Gaertn.), all of the herbicides provided at least a moderate degree of control of goosegrass, smooth crabgrass (Digitaria ischaemum (Schreb.) Muhl.), and redroot pigweed (Amaranthus retroflexus L.) at the respective typical field use rates. In general, trifluralin and amiben gave the best grass control and dinoseb the poorest. None of the herbicides effectively controlled common cocklebur (Xanthium pensylvanicum Wallr.) or ivyleaf morningglory (Ipomoea hederacea (L.) Jacq.). Trifluralin and EPTC did not control Pennsylvania smartweed (Polygonum pensylvanicum L.), common ragweed (Ambrosia artemisiifolia L.), and common lambsquarters (Chenopodium album L.). Chloropropham was ineffective on common ragweed. Simazine, chloropropham, and amiben controlled Pennsylvania smartweed while diuron, simazine, dinoseb, and amiben were especially effective on common lambsquarters. Distinctive patterns of nematode infestations were observed as a function of weed species.

Physiological Bases of Sugarbeet (Beta vulgaris) Tolerance to Foliar Application of Ethofumesate

Weed Science ◽  
1981 ◽  
Vol 29 (6) ◽  
pp. 648-654 ◽  
Author(s):  
David N. Duncan ◽  
William F. Meggitt ◽  
Donald Penner
Keyword(s):  
Beta Vulgaris ◽  
Foliar Application ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Water Soluble ◽  
Weed Species ◽  
Common Ragweed ◽  
Species Response ◽  
Redroot Pigweed ◽  
Photosynthesis And Respiration

Absorption, translocation, and metabolism of foliar-applied ethofumesate [(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulphonate] were studied to explain field observations showing differences in susceptibility among sugarbeet (Beta vulgarisL.), common ragweed (Ambrosia artemisiifoliaL.), redroot pigweed (Amaranthus retroflexusL.), and common lambsquarters (Chenopodium albumL.). In laboratory studies, two- to four-leaf seedlings of the highly susceptible species, redroot pigweed and common lambsquarter, absorbed greater amounts of14C-ethofumesate from foliar application than the moderately susceptible common ragweed and tolerant sugarbeet. Sugarbeet translocated very little14C from treated foliage to untreated plant tissue. All weed species translocated14C-ethofumesate to untreated leaf tissue when14C-ethofumesate was applied to seedlings at the two-leaf stage. Ethofumesate was translocated basipetally to the stem and root of two-leaf redroot pigweed and common lambsquarter seedlings. A high percentage of the14C was found in the water-soluble fraction in sugarbeet seedlings, indicating inactivation. The amount of metabolites recovered in the non-polar fraction depended on the stage of plant growth. Total photosynthesis and respiration in redroot pigweed was inhibited 4 h after foliar application and did not recover after 96 h. Uptake and evolution of CO2were also inhibited in sugarbeet leaves, but they recovered rapidly, depending on age of plant at treatment. The stage of plant development was the key factor determining species response to foliar treatments of ethofumesate in terms of absorption, metabolism, and total photosynthesis and respiration.

Examination of commercially available bird feed for weed seed contaminants

2020 ◽  
Vol 13 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Eric Oseland ◽  
Mandy Bish ◽  
Christine Spinka ◽  
Kevin Bradley
Keyword(s):  
Chenopodium Album ◽  
Carthamus Tinctorius ◽  
Grain Sorghum ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Amaranthus Palmeri ◽  
Weed Seed ◽  
Weed Species ◽  
Test Analysis ◽  
Proso Millet

AbstractIn 2016 and 2017, 98 separate commercially available bird feed mixes were examined for the presence of weed seed. All weed seed contaminants were counted and identified by species. Amaranthus species were present in 94 of the 98 bags of bird feed. Amaranthus species present in bird feed mixes included waterhemp [Amaranthus tuberculatus (Moq.) Sauer], redroot pigweed (Amaranthus retroflexus L.), Palmer amaranth (Amaranthus palmeri S. Watson), smooth pigweed (Amaranthus hybridus L.), and tumble pigweed (Amaranthus albus L.). Amaranthus palmeri was present in 27 of the 98 mixes. Seed of common ragweed (Ambrosia artemisiifolia L.), kochia [Bassia scoparia (L.) A.J. Scott], grain sorghum [Sorghum bicolor (L.) Moench], wild buckwheat (Fallopia convolvulus L., syn: Polygonum convolvulus), common lambsquarters (Chenopodium album L.), large crabgrass [Digitaria sanguinalis (L.) Scop.], and Setaria species were also present in bird feed mixes. A greenhouse assay to determine Amaranthus species seed germinability and resistance to glyphosate revealed that approximately 19% of Amaranthus seed in bird feed mixes are readily germinable, and five mixes contained A. tuberculatus and A. palmeri seed that were resistant to glyphosate. Results from linear regression and t-test analysis indicate that when proso millet (Panicum miliaceum L.), grain sorghum, and corn (Zea mays L.) were present in feed mixes, Amaranthus seed contamination was increased. The presence of proso millet and grain sorghum also increased contamination of grass weed species, while sunflower (Helianthus annuus L.) increased A. artemisiifolia contamination and safflower (Carthamus tinctorius L.) increased contamination of Bassia scoparia.

Response of Weeds to Soil Phosphorus and Potassium

Weed Science ◽  
1976 ◽  
Vol 24 (2) ◽  
pp. 194-201 ◽  
Author(s):  
C. S. Hoveland ◽  
G. A. Buchanan ◽  
M. C. Harris
Keyword(s):  
Sandy Loam ◽  
Plantago Lanceolata ◽  
Warm Season ◽  
Amaranthus Retroflexus ◽  
Weed Species ◽  
Cool Season ◽  
Stellaria Media ◽  
P Deficiency ◽  
Deficiency Symptoms ◽  
Redroot Pigweed

Ten warm-season and seven cool-season weed species were grown in the glasshouse on Hartsells fine sandy loam taken from field plots that had been in long-term fertility studies. The soil pH was 5.9 and phosphorus (P) levels ranged from 8 to 95 kg/ha and the potassium (K) levels from 40 to 213 kg/ha. Growth response to P and K levels was measured by dry herbage yield. Redroot pigweed (Amaranthus retroflexus L.), jimsonweed (Datura stramonium L.), and Florida beggarweed [Desmodium tortuosum (Sw.) DC] were the most responsive warm-season weed species to P, whereas chickweed [Stellaria media (L.) Cyrillo] was the most responsive cool-season weed to P. Extreme P deficiency symptoms were evident on species giving a high response to P. P-deficient plants were severely stunted and exhibited a characteristic reddish-purple color. Showy crotalaria (Crotalaria spectabilis Roth), tall morningglory [Ipomoea purpurea (L.) Roth], sicklepod (Cassia obtusifolia L.), Carolina geranium (Geranium carolinianum L.), and coffee senna (Cassia occidentalis L.) were the most tolerant to low soil P. Redroot pigweed, jimsonweed, and Florida beggarweed were the most responsive warm-season weeds to K. Wild mustard [Brassica kaber (DC.) L.C. Wheeler var. Pinnatifida (Stokes) L.C. Wheeler] and annual bluegrass (Poa annua L.) were the most responsive cool-season weeds to K. Potassium deficiency symptoms were characterized primarily by severe stunting. Buckhorn plantain (Plantago lanceolata L.), Carolina geranium, and curly dock (Rumex crispus L.) were the most tolerant cool-season weeds to low soil K. Generally, weeds were more sensitive to low soil-test P than K.

Weed seed destruction by arthropods and rodents in low-input soybean agroecosystems

1988 ◽  
Vol 3 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Gerald E. Brust ◽  
Garfield J. House
Keyword(s):  
Conventional Tillage ◽  
Ground Beetles ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Carabid Beetles ◽  
No Tillage ◽  
Weed Seed ◽  
Weed Species ◽  
Crop Species ◽  
Low Input

AbstractWeed seed consumption experiments involving comparison of rates of seed loss by seed feeders were conducted over a five-week period in low-input (no insecticide, low herbicide usage) conventional- and no-tillage soybean agroecosystems. Seeds of four broadleaf weed species (ragweed[Ambrosia artemisiifoliaL.], pigweed[Amaranthus retroflexusL.], sicklepod[Cassia obtusifoliaL.], and jimsonweed[Datura stramoniumL.]) and one grain crop species (wheat[Triticum aestivumL.]) were provided in a free choice design at densities of 10, 25, and 50 seeds/24 cm3. Approximately 2.3 times more seeds overall, and 1.4 times more large seeds as a group were consumed in notillage systems than in conventional-tillage systems. In our experimental low-input, notillage treatments, large ground beetles (Carabidae: Coleoptera) (15–25 mm) and mice preferentially fed on the larger seed species, while small carabids (< 15 mm), ants and crickets, fed almost exclusively on the smaller seed species. Carabid beetles were responsible for more than half of all seeds consumed. Laboratory and field studies indicated that ground beetles selectively consumed specific seed species. In conventional-tillage, ants were one of the dominant consumers of seeds, suggesting different patterns of resource partitioning in each tillage system. We suggest that selective feeding by arthropod seed feeders, in combination with their high number, could affect the species composition and possibly the abundance of weeds in low-input, no-tillage agroecosystems.

scholarly journals STUDY OF WEED FLORA OF MAIZE CROPS IN THE NISAVA DISTRICT

2018 ◽  
Vol 6 (4) ◽  
pp. 340-345
Author(s):  
Jelica Živić ◽  
Milić Vojinović ◽  
Ivica Stančić ◽  
Saša Petrović
Keyword(s):  
Chenopodium Album ◽  
Datura Stramonium ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Weed Species ◽  
Convolvulus Arvensis ◽  
Maize Crop ◽  
Time Of Application ◽  
Cultivated Plant ◽  
The Right

The damage from the present weeds in maize crop is shown by the reduction of yield in almost every year and their suppression is completely economically justified. The right selection of herbicides mostly depends on the presence of dominant weed species and the time of application. The paper presents the distribution and existence of economically harmful, invasive and quarantine weed species (Abutilon theophrasti, Agropyrum repens, Amaranthus retroflexus, Ambrosia artemisiifolia, Capsela bursa-pastoris, Chenopodium album, Chenopodium hybridum, Cirsium arvense, Convolvulus arvensis, Datura stramonium, Avena fatua, Calystegia sepium, …) on ten locations of maize crops in the Nisava district. Estimation of the species presence was done in two shootings (May and August) on scale 1-4 (1 - species appears individually and occupy up to 5% of the surface, 2 - appears and occupies 5-25% of the surface, 3 - appears often and occupies 25-50% of the surface, 4 - the species prevails over the cultivated plant and occupies over 50% of the surface).

scholarly journals Weeds in Organic Bean Crops (Phaseolus vulgaris L.) (Fabaceae Lindl., Fabales)

2020 ◽  
Vol 69 (3-4) ◽  
pp. 110-118
Author(s):  
Dejana Džigurski ◽  
Branka Ljevnaić-Mašić ◽  
Ljiljana Nikolić
Keyword(s):  
Invasive Species ◽  
Phaseolus Vulgaris ◽  
Humus Content ◽  
Climatic Conditions ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Weed Species ◽  
Invasive Weed ◽  
Weakly Alkaline ◽  
Weed Flora

SummaryIn the organic bean crops (Phaseolus vulgaris) grown in open cultivation during the vegetation period of 2012, 14 weed species were found in the villages Ljutovo and Orom. The percentage of invasive species was 28.57%. Ambrosia artemisiifolia was characterized as highly invasive, Sorghum halepense as sporadically invasive, and Amaranthus retroflexus and Datura stramonium as potentially invasive species. Low diversity and low density of weed flora in organic bean crops are the factors causing a high percentage of invasive species in the floristic composition, so monitoring of these species is necessary. The weed flora dominated by therophytes (71.43%), the dominance of weed-ruderal plants (64.29%), and the presence of widespread taxa in the bean crops indicate strong anthropogenic influence and instability of the weed flora. The largest number of the weed species bloom from June to August (71.43%). According to the ecological analysis of the weed flora, the studied agroecosystems were characterized as moderately arid (F-2.36), neutral to weakly alkaline (R-3.07), eutrophic-mesotrophic (N-3.71), well-aerated (D-3.64), non-saline (S-, 78.57%) with medium humus content (H-2.86), favorable light (L-3.86) and temperature (T-4.14) regime, and with temperate continental climatic conditions (K-2.93). Correlation analysis showed that invasive weed species began to bloom later and favored well-aerated and warmer habitats compared to other weeds. PCA analysis singled out habitat aeration and salinity as the main factors separating weeds in organic bean crops.

scholarly journals Weed resistance to herbicides

2020 ◽  
Vol 29 (2) ◽  
pp. 79-96
Author(s):  
Sava Vrbničanin
Keyword(s):  
Herbicide Resistance ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Target Site ◽  
Weed Species ◽  
Ps Ii ◽  
Target Site Resistance ◽  
Resistance To Herbicides ◽  
Als Inhibitors ◽  
Weed Resistance

Weed resistance to herbicides represents the acquired resistance of individuals to complete the life cycle and leave offspring in the conditions of extended exposure to the same herbicide, i.e. herbicides of the same mechanism of action to which they were sensitive at the beginning of the application. Based on the herbicide resistance mechanisms, all processes can be grouped as follows: target-site resistance, non-target-site resistance, cross-resistance and multiple-resistance. Currently, herbicide resistance has been reported in 514 cases (species x site of action) worldwide, in 262 weed species (152 dicotyledons, 110 monocotyledons). Many of those biotypes are resistant to als inhibitors, PS II inhibitors, EPSPS inhibitors and ACC-ase inhibitors. The higher degree of resistance to als inhibitors has been confirmed in the following weed species: Amaranthus retroflexus, Sorghum halepense, Ambrosia artemisiifolia and Helianthus annuus.

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