Regrowth of Quackgrass (Agropyron repens) Following Postemergence Applications of Haloxyfop and Sethoxydim

Weed Science ◽  
1986 ◽  
Vol 34 (5) ◽  
pp. 664-668 ◽  
Author(s):  
David E. Stoltenberg ◽  
Donald L. Wyse
Keyword(s):  
Propanoic Acid ◽  
Stages Of Development ◽  
Leaf Stage ◽  
Stages Of Growth ◽  
Crown Tissue ◽  
Advanced Stages ◽  
Rhizome Bud ◽  
Herbicide Activity ◽  
Residual Herbicide ◽  
Agropyron Repens

Previous research has shown that haloxyfop {2-[4-[[3-chloro-5-(trifluoromethyl)-2-pyridinyl] oxy] phenoxy] propanoic acid} and sethoxydim {2-[1-(ethoxyimino)butyl-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} give less control of quackgrass [Agropyron repens(L.) Beauv. # AGRRE] when applied at the five- to seven-leaf stage compared to the three- to four-leaf stage. Current research indicates that reduced control of quackgrass in the eight-leaf stage, compared to the four-leaf stage, was not due to reduced herbicide retention on leaves or to changes in residual herbicide activity in the soil following postemergence applications. The efficacy of both herbicides on rhizome bud kill did not change between the four- and eight-leaf stages following application to the foliage. However, the efficacy of both herbicides on crown tissue bud viability was less at the eight-leaf stage. Rhizome sink intensity (the capacity to accumulate radiolabel) was similar at both stages of development following14C-haloxyfop and14C-sethoxydim application to either upper or lower leaves. Crown tissue sink intensity was significantly less at the eight-leaf stage compared to the four-leaf stage following14C-sethoxydim application to either upper or lower leaves and following14C-haloxyfop application to lower leaves. These data suggest that crown bud regrowth contributes substantially to reduced control of quackgrass in advanced stages of growth following applications of haloxyfop and sethoxydim.

Quackgrass (Agropyron repens) Control in Potatoes (Solanum tuberosum) by Fluazifop

Weed Science ◽  
1988 ◽  
Vol 36 (3) ◽  
pp. 363-366 ◽  
Author(s):  
Jerry A. Ivany
Keyword(s):  
Solanum Tuberosum ◽  
Field Studies ◽  
Potato Yield ◽  
Russet Burbank ◽  
Racemic Mixture ◽  
Propanoic Acid ◽  
Leaf Stage ◽  
Application Rates ◽  
Agropyron Repens

In greenhouse and field studies, fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid} controlled quackgrass [Agropyron repens(Beauv.) # AGRRE] in potato (Solanum tuberosumL. ‘Russet Burbank’). Quackgrass control with fluazifop at 0.25 and 0.5 kg ai/ha in the greenhouse was greatest with application at the two-leaf stage compared with the four-and six-leaf stages. Control was not affected by rhizome length, with similar control obtained of plants grown from 2- and 10-node rhizome pieces. Removal of quackgrass shoots at 6 or 24 h after treatment resulted in decreased control at application rates of 0.25 and 0.5 kg/ha. Fluazifop at 0.5 kg/ha controlled quackgrass treated at the four-leaf stage. The active enantiomer of fluazifop at half the rate of the racemic mixture controlled the quackgrass to the same extent. Fluazifop did not affect potato yield.

Response of quackgrass biotypes to glyphosate and quizalofop

1991 ◽  
Vol 71 (3) ◽  
pp. 803-810 ◽  
Author(s):  
François J. Tardif ◽  
Gilles D. Leroux
Keyword(s):  
Negative Correlation ◽  
Growth Control ◽  
Total Biomass ◽  
Leaf Stage ◽  
Stages Of Growth ◽  
Elytrigia Repens ◽  
Shoot Number ◽  
Rhizome Bud ◽  
Treatment Tolerance ◽  
Rhizome Buds

The response to glyphosate and quizalofop of five quackgrass (Elytrigia repens (L.) Nevski) biotypes treated at the three- to four-leaf and six- to seven-leaf stage was tested. Shoot and rhizome-bud control 1 yr after treatment did not differ among biotypes treated at the three-to four-leaf stage regardless of the herbicides and rates. At the six- to seven-leaf stage, difference in shoot control between the most tolerant and the most sensitive biotypes was 54 and 40% after treatment with quizalofop at 100 and 150 g a.i. ha−1, respectively. Shoot control at the six- to seven-leaf stage ranged between 59 and 97%, with glyphosate at 450 g a.i. ha−1. When averaged over all treatments and stages of growth, control of shoot number was positively correlated with control of rhizome bud number. A negative correlation existed between the percent shoot control at the six- to seven-leaf stage and the number of tillers, rhizomes, and rhizome buds, and with the total biomass of the biotypes at time of treatment with quizalofop at 100 g ha−1. Leaf retention on the lower leaves of plants at the three- to four-leaf stage varied among biotypes, but was not related to treatment tolerance. Key words: Glyphosate, quizalofop, rhizome buds, shoot control, Elytrigia repens

Quackgrass (Agropyron repens) Biotype Response to Sethoxydim and Haloxyfop

Weed Science ◽  
1989 ◽  
Vol 37 (1) ◽  
pp. 107-111 ◽  
Author(s):  
Elifas N. Alcantara ◽  
Donald L. Wyse ◽  
Joseph M. Spitzmueller
Keyword(s):  
Differential Response ◽  
Stages Of Development ◽  
Leaf Stage ◽  
Differential Development ◽  
Two Stages ◽  
Rhizome Development ◽  
Agropyron Repens

Crown bud, tiller, and rhizome development was studied in 10 quackgrass biotypes at two stages (three-to four- and seven- to eight-leaf stages) of development to determine if differential development of these structures influenced control with sethoxydim and haloxyfop. There was a differential response among the 10 biotypes to both sethoxydim and haloxyfop at both stages of development. The biotypes differed in the number of crown buds, tillers, and rhizomes that formed at both stages of development. In the three- to four-leaf stage, the biotypes with the greatest number of crown buds were the most difficult to control. These results suggest that in the susceptible stage (three-to four-leaf) the quackgrass biotypes with the least number of crown buds will be the easiest to control; however, by the time all the biotypes reach the seven- to eight-leaf stage even the biotypes with the lowest number of crown buds have enough crown buds that they become difficult to control with either sethoxydim or haloxyfop.

Enhancement of Herbicide Activity with an Isoparaffinic Oil Carrier

Weed Science ◽  
1971 ◽  
Vol 19 (6) ◽  
pp. 701-705 ◽  
Author(s):  
R. J. Burr ◽  
G. F. Warren
Keyword(s):  
Acetic Acid ◽  
Cyperus Rotundus ◽  
Setaria Viridis ◽  
Ipomoea Hederacea ◽  
Purple Nutsedge ◽  
Green Foxtail ◽  
Herbicide Activity ◽  
Dichlorophenoxy Acetic Acid ◽  
Agropyron Repens

Several herbicides were tested in the greenhouse on ivyleaf morningglory (Ipomoea hederacea(L.) Jacq.), green foxtail (Setaria viridis(L.) Beauv.), purple nutsedge (Cyperus rotundusL.), and quackgrass (Agropyron repens(L.) Beauv.) to determine the degree of enhancement in activity that could be obtained with an isoparaffinic oil carrier applied at 140 L/ha. The enhancement varied with the herbicide and with the species, ranging from 16-fold enhancement with 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) and 2-sec-butyl-4,6-dinitrophenol (dinoseb) on ivyleaf morningglory to no enhancement of atrazine activity on purple nutsedge and quackgrass or (2,4-dichlorophenoxy)acetic acid (2,4-D) activity on quackgrass and ivyleaf morningglory. An oil adjuvant was less effective in enhancing dinoseb and 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) activity than was the isoparaffinic oil carrier. Also, the isoparaffinic oil carrier emulsified in water was less effective than the undiluted oil in enhancing dinoseb activity on green foxtail, even though equal volumes of the isoparaffinic oil were applied.

Morphological variations of Phrosina semilunata Risso, 1822 juveniles (Crustacea: Amphipoda: Hyperiidea), new evidence from the Gulf of Mexico

Zootaxa ◽  
2021 ◽  
Vol 4995 (3) ◽  
pp. 594-600
Author(s):  
MARCO VIOLANTE-HUERTA ◽  
LAURA SANVICENTE-AÑORVE ◽  
MARGARITA HERMOSO-SALAZAR ◽  
AURORA MARRÓN-BECERRA
Keyword(s):  
Gulf Of Mexico ◽  
Monotypic Genus ◽  
Stages Of Development ◽  
Morphological Variations ◽  
Stages Of Growth ◽  
Early Stages ◽  
Southern Gulf Of Mexico ◽  
New Evidence ◽  
Lack Of Knowledge

Lack of knowledge of morphological variations during growth of amphipod crustaceans can result in misidentification of species. In this study, we advance the knowledge of morphological variations of juveniles of the monotypic genus Phrosina Risso, 1822 collected in the oceanic province of the southern Gulf of Mexico. The juveniles differed from the adults mainly in the morphology of pereopods 3 & 4 in that the carpal process is parallel to the propodus, also the rami of the pleopoda consist of only four segments, uropoda 3 are more lanceolate, and the uropoda bear a large prominent spine terminally. These morphological variations have not been described for the species previously. Therefore, the current observations enrich the description of P. semilunata in the early stages of growth and support the need for further taxonomical studiest that could help identify species at different stages of development.  

Water status and yield of sunflowers (Helianthus annuus) subjected to water stress during four stages of development

1977 ◽  
Vol 89 (3) ◽  
pp. 663-666 ◽  
Author(s):  
N. Sionit
Keyword(s):  
Water Stress ◽  
Seed Yield ◽  
Sunflower Seed ◽  
Oil Content ◽  
Water Status ◽  
Dry Weight ◽  
Stages Of Development ◽  
Stages Of Growth ◽  
Head Formation ◽  
Total Dry Weight

SummaryThe effects on seed yield of two levels of water stress at four stages of development were investigated in two varieties of sunflower, Krasnodarets and Record. The plants were grown from seed in large pots in an air-conditioned glasshouse at 26/20 °C and 70% relative humidity, with natural summer illumination. They were subjected to water stress before head formation, during head formation, during flowering, and during seed development.The leaf water potential of plants subjected to a water stress of – 16 bars returned to normal after rewatering, but plants subjected to – 23 bars did not return to their prestress level and some leaves died. A water stress of – 16 bars caused no significant reduction in dry weight of the vegetative structures, but stress at all stages of growth reduced seed yield. A water stress of – 23 bars reduced both total dry weight and seed yield at all stages of growth, seed yield being reduced more by a stress of – 23 bars than of – 16 bars. Oil content was slightly reduced by water stress.Water stress during anthesis reduced sunflower seed yield more than during later stages of development.

scholarly journals Efficiency of Isolated and Associated Herbicides to Control Glyphosate-Resistant Sourgrass

2019 ◽  
Vol 37 ◽  
Author(s):  
M. CASSOL ◽  
M.D. MATTIUZZI ◽  
A.J.P. ALBRECHT ◽  
L.P. ALBRECHT ◽  
L.C. BACCIN ◽  
...  
Keyword(s):  
Dry Matter ◽  
Economic Importance ◽  
Herbicide Application ◽  
Stages Of Development ◽  
Great Economic Importance ◽  
Full Flowering ◽  
Efficient Control ◽  
Advanced Stages ◽  
Control Evaluation ◽  
Treatment Application

ABSTRACT: Sourgrass is one of the weeds of great economic importance in Brazil due to its difficulty of control and conditions that allow its emergence and development throughout the year. Thus, this study aimed to evaluate the effectiveness of clethodim and haloxyfop applied alone or mixed with glyphosate and other herbicides to control glyphosate-resistant sourgrass at different stages of development. For this, three experiments were conducted in the field: in experiment 1, the herbicides were applied in sourgrass plants with 6 to 8 tillers; and in experiments 2 and 3, when plants were at full flowering, with up to 18 tillers. After treatment application, visual evaluations were performed at 14, 21, 28, 35, 42, 49, and 56 days after application (DAA) in experiment 1 and at 7, 14, 21, 28, and 35 DAA in experiments 2 and 3. Also in experiment 3, the shoot of remaining plants was collected in the last control evaluation to measure the dry matter. In experiment 1, the treatment glyphosate + clethodim presented a satisfactory control close to 90%, but after 35 DAA, sourgrass plants started showing significant resprouts, decreasing the control. In experiments 2 and 3, treatments showed no control above 90% and the herbicides clethodim and haloxyfop had similar final control when in mixture with glyphosate. Therefore, the isolated herbicide application at the tested doses was not sufficient for efficient control of sourgrass at more advanced stages of development.

scholarly journals Antifungal Pipeline

2021 ◽  
Vol 11 ◽  
Author(s):  
Todd Patrick McCarty ◽  
Peter G. Pappas
Keyword(s):  
Antifungal Agents ◽  
Fungal Infections ◽  
Mechanisms Of Action ◽  
Invasive Fungal Infections ◽  
Fungal Diseases ◽  
Stages Of Development ◽  
The Past ◽  
Clinical Mycology ◽  
Dosing Regimens ◽  
Advanced Stages

In many ways, fungal diseases are forgotten or neglected. Given the significantly lower frequency compared to similar bacterial etiologies across the spectrum of infectious syndromes, it makes sense that anti-bacterial agents have seen the bulk of development in recent decades. The vast majority of new antifungal medications approved for use in the past 10 years have been new versions in the same class as existing agents. Clinical mycology is crying out for new mechanisms of action in the setting of rising resistance and emergence of new organisms. Fortunately, this trend appears to be reversing. There are numerous agents in advanced stages of development offering novel dosing regimens and mechanisms of action to combat these threats. Herein we review seven antifungal agents that we hope to see come to market in the coming years to aid physicians in the treatment of mucocutaneous and invasive fungal infections.

THE SYNTHETIC PRODUCTION OF OAT VARIETIES RESISTANT TO RACE 6 AND CERTAIN OTHER PHYSIOLOGIC RACES OF OAT STEM RUST

1937 ◽  
Vol 15c (2) ◽  
pp. 58-69 ◽  
Author(s):  
J. N. Welsh
Keyword(s):  
Seedling Stage ◽  
The Other ◽  
Puccinia Graminis ◽  
Stages Of Growth ◽  
Boot Stage ◽  
Advanced Stages ◽  
Physiologic Races ◽  
Pure Lines ◽  
Heading Stage ◽  
Single Variety

At the present time, oat varieties that are classed as resistant to Puccinia graminis Avenae Erikss. & Henn. are only resistant to a certain number of the ten physiologic races. With the object of combining in a single variety resistance to as many races as possible, a cross was made between the varieties Hajira Strain and Joanette Strain. Hajira Strain is susceptible to Races 4, 6, 8, and 10, and Joanette Strain to Races 2, 6, 7, 8, and 9. The latter variety gives an indeterminate reaction to Races 5 and 10. Both parents are susceptible to Races 6 and 8.From this cross 93 pure lines were obtained. Under greenhouse conditions, 71 were resistant at the seedling stage to Race 6 at 60° F. At 65°–70° F., approximately one-third of these were resistant to Race 6, one-third semi-resistant, and one-third susceptible. At more advanced stages of growth, namely, fifth-leaf, boot, and heading, representative lines from each of these classes were resistant to Race 6 at 60° F. At 65°–70° F. all showed regional resistance: at the fifth-leaf stage, the tip end of the uppermost leaf only was susceptible; at the boot stage, numerous pustules were present on the uppermost node and internode but the remaining parts were free from infection; at the heading stage, only one or two fairly large pustules occurred on the uppermost node or internode.Six lines that were consistently resistant to Race 6 at 60° F. and 65°–70° F. were tested at the seedling stage at 60°, 65°–70° F., and 75°–80° F., to Races 1, 2, 3, 4, 5, 6, 7, 8, and 10. At the low and intermediate temperatures, these lines were resistant to the nine races. At the high temperature, they were susceptible to Race 6, gave an indeterminate reaction to Races 1, 4, and 5, and were resistant to all the other races.Under field conditions, six lines classed as resistant at 65°–70° F., five classed as semi-resistant, and four as susceptible, were tested to Race 6. All these lines behaved similarly: infections of a semi-resistant type appeared on the uppermost internodes, while other parts of the plants were free from infection.The standard varieties used as checks, namely, Hajira Strain, Joanette Strain, White Russian, and Victory, were susceptible to Race 6 in all the greenhouse experiments, and, with the exception of White Russian, in the field test. In the latter test, White Russian was semi-resistant.

Reduced Transpiration and Increased Water Efficiency by Diuron in Corn (Zea mays)

Weed Science ◽  
1980 ◽  
Vol 28 (2) ◽  
pp. 180-185 ◽  
Author(s):  
Shabir Ahmed ◽  
R. A. Fletcher
Keyword(s):  
Zea Mays ◽  
Active Component ◽  
Dry Weight ◽  
Water Efficiency ◽  
Commercial Formulation ◽  
Leaf Stage ◽  
Stages Of Growth ◽  
Shoot Dry Weight ◽  
Low Concentrations ◽  
Corn Plants

Of several herbicides tested on both monocotyledon and dicotyledon species, diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] was found to be the most effective in reducing transpiration in corn (Zea maysL.) plants; a reduction of 40% occurred. It was established that diuron was the active component in reducing transpiration, and not the additives in the commercial formulation (Karmex) used in this study. Foliar applications of low concentrations (0.035 to 0.56 kg/ha) of diuron effectively reduced transpiration in both cultivars (Pioneer 3780A and Pride 1108) of corn plants, at all stages of growth tested (from 3- to 10-leaf stage). This effect of diuron on reduced transpiration occurred when the supply of water or nutrients to the corn plants was either limiting or non-limiting. The reduction of transpiration of corn plants after treatment also prevented the leaves from wilting and becoming senescent. This effect was persistent over 16 days. Diuron treatment increased the water efficiency of the plants and this effect was more pronounced when water was limiting. Compared to the control, the treated plants used up to 68% less water for each gram of shoot dry weight produced. The increase in water efficiency indicates that transpiration was reduced more than photosynthesis.

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