Evaluation of Cycloate Followed by Evening Two-Leaf–Stage Phenmedipham Application in Fresh Market Spinach

2016 ◽  
Vol 30 (2) ◽  
pp. 464-471 ◽  
Author(s):  
Ran N. Lati ◽  
Beiquan Mou ◽  
John S. Rachuy ◽  
Steven A. Fennimore
Keyword(s):  
Light Intensity ◽  
Weed Control ◽  
Growing Season ◽  
Field Studies ◽  
High Light Intensity ◽  
Time Of Day ◽  
Light Conditions ◽  
Fresh Market ◽  
Reference Treatment ◽  
Leaf Stage

Fresh market spinach has one primary herbicide, cycloate, which does not control all weeds. Previous studies demonstrated that cycloate PRE followed by (fb) phenmedipham at the four-leaf spinach stage is a safe and effective treatment. However, this treatment is not useful for the main growing season of fresh spinach due to its short crop cycle and the 21-d preharvest interval requirement of phenmedipham. This study evaluates the potential to use the combination of cycloate PRE fb phenmedipham on two-leaf spinach. Greenhouse and field studies were conducted in 2014 using three spinach varieties with low (‘Nordic' and ‘Sardinia') and high (‘Regal') tolerance to phenmedipham. Greenhouse studies revealed that phenmedipham at 90 g ai ha−1was safe to Regal when applied at the two-leaf stage. Sardinia was more susceptible to phenmedipham injury under high (310 W m−2) light conditions than low (258 W m−2) light conditions. Impact of time of day on phenmedipham safety was evaluated in the field: day-long exposure to high light intensity following morning applications vs. evening applications fb exposure to low light intensity. Injury estimations taken 3 d after treatment (DAT) were lower for evening than for morning applications. Nonetheless, injury 11 DAT and spinach yield evaluations found no differences between morning and evening applications. Subsequently, cycloate (1,700 g ha−1) PRE fb phenmedipham (90 and 180 g ha−1) applied in the evening at the two-leaf stage was evaluated. A reference treatment was cycloate PRE fb phenmedipham (270 g ha−1) at the four-leaf stage. Treatments with cycloate fb two-leaf phenmedipham at 90 and 180 g ha−1were safe to spinach and improved weed control compared to cycloate alone. Cycloate fb 180 g ha−1phenmedipham at the two-leaf stage reduced weed biomass by 88% compared to cycloate alone. This level of weed control was similar to the reference treatment. Results here show that phenmedipham applied at the two-leaf stage is safe to fresh market spinach and it has the potential to be used during most of the fresh spinach growing season.

Weed Management in Fresh Market Spinach (Spinacia oleracea) with Phenmedipham and Cycloate

2015 ◽  
Vol 29 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Ran N. Lati ◽  
John S. Rachuy ◽  
Steven A. Fennimore
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Spinacia Oleracea ◽  
Field Studies ◽  
High Tolerance ◽  
Fresh Market ◽  
Leaf Stage ◽  
Hand Weeding ◽  
Potential Use ◽  
Better Than

Fresh market spinach has limited herbicides available and weed management in this crop is dependent on hand-weeding. Phenmedipham is a POST herbicide registered for use on spinach grown for processing or for seed, but not fresh market spinach. This study evaluates the potential use of phenmedipham alone and in combination with cycloate for weed control in fresh spinach production. Greenhouse and field studies were conducted in 2013 using two spinach varieties known to have low and high tolerance to phenmedipham. The greenhouse studies showed that phenmedipham at 270 and 550 g ai ha−1 was safe to spinach when applied at the four-leaf stage for the low- and high-tolerance varieties, respectively. Phenmedipham was evaluated alone (550 g ha−1) and applied to the four-leaf stage in two varieties. Subsequently, a second experiment evaluated cycloate (1,700 g ha−1) followed by (fb) phenmedipham at several rates (90, 180, and 270 g ha−1). Phenmedipham alone (550 g ha−1) did not result in crop injury when applied to four-leaf spinach; however, the weed control was not better than cycloate alone. When applied as a sequential treatment following cycloate, all phenmedipham rates were safe to spinach and significantly improved weed control compared to cycloate alone. Cycloate fb phenmedipham at 270 g ha−1 provided 87% weed control relative to cycloate alone. This level of weed control was similar to the cycloate plus hand-weeding treatment, which provided 98% control. Results here show that cycloate fb phenmedipham improves weed control compared to cycloate alone, and has the potential to reduce hand-weeding costs in the fresh spinach production.

scholarly journals Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by <i>Emiliania huxleyi</i>

2017 ◽  
Vol 14 (24) ◽  
pp. 5693-5704 ◽  
Author(s):  
Gabriella M. Weiss ◽  
Eva Y. Pfannerstill ◽  
Stefan Schouten ◽  
Jaap S. Sinninghe Damsté ◽  
Marcel T. J. van der Meer
Keyword(s):  
Light Intensity ◽  
Environmental Conditions ◽  
Hydrogen Isotope ◽  
Isotope Fractionation ◽  
Emiliania Huxleyi ◽  
High Light Intensity ◽  
High Light ◽  
Light Conditions ◽  
Low Light ◽  
Long Chain

Abstract. Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

Fluazifop-P Tank-Mixtures with Clethodim for Annual Grass Control in Flax (Linum usitatissimum)

1994 ◽  
Vol 8 (4) ◽  
pp. 673-678 ◽  
Author(s):  
David A. Wall
Keyword(s):  
Weed Control ◽  
Active Ingredient ◽  
Linum Usitatissimum ◽  
Field Studies ◽  
Wild Oat ◽  
Annual Grass ◽  
Foliar Injury ◽  
Leaf Stage ◽  
Green Foxtail

Field studies were undertaken in 1992 and 1993 to investigate the control of wild oat and green foxtail in flax with reduced rates of fluazifop-P and clethodim applied as tank-mixtures. Fluazifop-P plus clethodim at 50 + 18 g ai/ha controlled wild oat and green foxtail and was as effective as full rates of either herbicide applied alone. These rates represent a 20% reduction in total amount of active ingredient required to control wild oat and green foxtail. Application of fluazifop-P, and/or clethodim prior to the 3- to 4-leaf stage failed to control late emerging grass weeds. Application of graminicide mixtures at or after the 3- to 4-leaf stage controlled late emerging grass weeds and did not affect flax yield. When applied late, fluazifop-P at 175 g/ha tended to reduce flax yield, although weed control was acceptable and no foliar injury was observed following treatment. The efficacy of graminicide mixtures was reduced by addition of bromoxynil plus MCPA to the spray mix.

Ethalfluralin Activity in Cucumber (Cucumis sativus)

Weed Science ◽  
1982 ◽  
Vol 30 (5) ◽  
pp. 498-502 ◽  
Author(s):  
Jeffrey F. Derr ◽  
Thomas J. Monaco
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Weed Control ◽  
Cucumis Sativus ◽  
Environmental Conditions ◽  
Heavy Rain ◽  
Field Studies ◽  
Herbicidal Activity ◽  
Fresh Weight ◽  
Fresh Market

In greenhouse studies, soil organic matter reduced the herbicidal activity of ethalfluralin (N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl)benzenamine). Fifty percent inhibition (I5.0) values for barnyardgrass [Echinochloa crus-galli(L.) Beauv.] stand, injury, and shoot fresh weight increased as the soil organic-matter level increased. No difference in ethalfluralin tolerance was found among 16 cucumber (Cucumis sativusL.) cultivars. When grouped according to market type, fresh market cultivars tended to be injured more than pickling cultivars by excess ethalfluralin. Both shoots and roots of cucumber absorbed the herbicide, but exposure of roots to ethalfluralin was more toxic than exposure of shoots. Field studies indicated that with certain edaphic and environmental conditions, cucumbers can be injured by preemergence applications of ethalfluralin. Injury was greatest in a low organic-matter soil following a heavy rain. Ethalfluralin at 1.3 kg/ha gave adequate weed control in 1 and 3% organic-matter soils, but not in a 9% organic-matter soil.

Response of Corn to Preemergence and Postemergence Applications of Saflufenacil

2009 ◽  
Vol 23 (3) ◽  
pp. 331-334 ◽  
Author(s):  
Nader Soltani ◽  
Christy Shropshire ◽  
Peter H. Sikkema
Keyword(s):  
Weed Control ◽  
Petroleum Hydrocarbons ◽  
Field Studies ◽  
Corn Yield ◽  
Yield Losses ◽  
Leaf Stage ◽  
Field Corn ◽  
Corn Field ◽  
Use Pattern

Saflufenacil (BAS 800H) is a new herbicide being developed by BASF for PRE broadleaf weed control in corn. Field studies were conducted at two Ontario locations in 2006 and 2007 to evaluate the tolerance of field corn to PRE and POST (spike and two- to three-leaf corn) applications of saflufenacil at 50, 100, and 200 g ai/ha with and without an adjuvant (surfactant blend + solvent [petroleum hydrocarbons]; 1% v/v). Saflufenacil applied PRE reduced corn height by as much as 12% with the highest rate of 200 g/ha; however, corn yield was not affected. When saflufenacil was applied without an adjuvant to corn at the spike stage, injury was as much as 12%, 7 d after treatment (DAT). However, corn height and yield were not affected. Saflufenacil applied POST to two- to three-leaf corn at 50 to 200 g/ha without an adjuvant resulted in as much as 25% injury and reduced corn height 31% but did not affect yield. Adding an adjuvant to POST applications of saflufenacil caused as much as 4 and 99% injury, reduced corn height 13 and 77%, and reduced corn yield 0 and 59% when applied to corn at the spike and at the two- to three-leaf stages, respectively. Based on these results, saflufenacil applied PRE can be safely used in corn at rates up to 200 g/ha. Saflufenacil applied to corn at the spike and two- to three-leaf stage at 50 or 100 g/ha without an adjuvant demonstrated acceptable corn tolerance and may allow for the use of saflufenacil beyond the proposed PRE use pattern. In contrast, applying saflufenacil POST with an adjuvant to spike and two- to three-leaf stage corn resulted in unacceptable injury and yield losses in field corn.

The Critical Period of Weed Control in Grain Corn (Zea mays)

Weed Science ◽  
1992 ◽  
Vol 40 (3) ◽  
pp. 441-447 ◽  
Author(s):  
Michael R. Hall ◽  
Clarence J. Swanton ◽  
Glenn W. Anderson
Keyword(s):  
Zea Mays ◽  
Leaf Area ◽  
Weed Control ◽  
Critical Period ◽  
Field Studies ◽  
Southern Ontario ◽  
Leaf Stage ◽  
Individual Leaf ◽  
Logistic Equations ◽  
Weed Interference

Field studies were conducted in southern Ontario to determine the critical period of weed control in grain corn and the influence of weed interference on corn leaf area. The Gompertz and logistic equations were fitted to data representing increasing durations of weed control and weed interference, respectively. The beginning of the critical period varied from the 3- to 14-leaf stages of corn development However, the end of the critical period was less variable and ended on average at the 14-leaf stage. Weed interference reduced corn leaf area by reducing the expanded leaf area of each individual leaf and accelerating senescence of lower leaves. In addition, weed interference up to the 14-leaf stage of corn development impeded leaf expansion and emergence in 1989.

Efficacy and Dissipation of Pyroxasulfone and Three Chloroacetamides in a Tennessee Field Soil

Weed Science ◽  
2011 ◽  
Vol 59 (4) ◽  
pp. 574-579 ◽  
Author(s):  
Thomas C. Mueller ◽  
Lawrence E. Steckel
Keyword(s):  
Weed Control ◽  
Half Life ◽  
Dissipation Rate ◽  
Resistance Management ◽  
Growing Season ◽  
Field Studies ◽  
Poor Correlation ◽  
Field Soil ◽  
Rainfall Patterns ◽  
Residual Control

Field studies were conducted in Knoxville, TN, over a 2-yr period (2007 and 2008) to determine the field dissipation rate and efficacy of pyroxasulfone, acetochlor, dimethenamid, ands-metolachlor to broadleaf signalgrass. Depending on rainfall patterns, pyroxasulfone at 209 g ai ha−1provided broadleaf signalgrass control of > 75%, which was equal to or superior to acetochlor at 1,740 g ai ha−1, dimethenamid at 1,500 g ai ha−1ands-metolachlor at 1,420 g ai ha−1. Pyroxasulfone provided residual control into the growing season and provides a tool for resistance management of later-emerging weeds. Herbicide dissipation was rapid in all soils (half-life usually < 20 d), although it was slower in a dry year. The order of herbicide dissipation and half-life in days in the 2 yr was acetochlor (3.5, 5 d) > dimethenamid (5, 9 d) >s-metolachlor (8.8, 27 d) > pyroxasulfone (8.2, > 71 d). There was poor correlation between observed weed control at 45 d after treatment and chemically determined herbicide concentrations at that same time, with ∼ 40% difference in 2007 and ∼ 50% difference in 2008.

Cotton Planting Date Affects The Critical Period of Benghal Dayflower (Commelina benghalensis) Control

Weed Science ◽  
2009 ◽  
Vol 57 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Theodore M. Webster ◽  
Timothy L. Grey ◽  
J. Timothy Flanders ◽  
A. Stanley Culpepper
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Maximum Yield ◽  
Growing Season ◽  
Field Studies ◽  
Cotton Field ◽  
Commelina Benghalensis ◽  
Critical Range ◽  
Benghal Dayflower

Benghal dayflower (formerly known as tropical spiderwort) is one of the most troublesome weeds in Georgia cotton. Field studies were conducted from 2003 to 2005 to evaluate the relationship between the duration of Benghal dayflower interference and cotton yield to establish optimum weed-control timing. To determine the critical period of weed control (CPWC), Benghal dayflower interference with cotton was allowed or prohibited in 2-wk intervals between 0 to 12 wk after crop planting. Maximum yield loss from Benghal dayflower in May-planted cotton was 21 to 30% in 2004 and 2005, whereas cotton planting delayed until June resulted in maximum yield losses of 40 to 60%. June-planted cotton had a CPWC of 190 to 800 growing degree days (GDD) in 2004 (52-d interval beginning at 16 d after planting [DAP]) and 190 to 910 GDD in 2005 (59-d interval beginning at 18 DAP). In contrast, May-planted cotton in 2005 had a narrower CPWC interval of 396 to 587 GDD (18 d) that occurred 3 wk later in the growing season (initiated at 39 DAP). May-planted cotton in 2004 did not have a critical range of weed-free conditions. Instead, a single weed removal at 490 GDD (44 DAP) averted a yield loss greater than 5%. It is recommended that fields infested with Benghal dayflower be planted with cotton early in the growing season to minimize weed interference with the crop.

Time of Day Impacts Postemergence Weed Control in Corn

2009 ◽  
Vol 23 (3) ◽  
pp. 346-355 ◽  
Author(s):  
Christie L. Stewart ◽  
Robert E. Nurse ◽  
Peter H. Sikkema
Keyword(s):  
Light Intensity ◽  
Weed Control ◽  
Air Temperature ◽  
Ambient Air ◽  
Field Trials ◽  
Time Of Day ◽  
Weed Species ◽  
Application Timing ◽  
Reducing Costs ◽  
Species Specific

Field trials were conducted from 2005 to 2007 at two locations in southwestern Ontario to investigate how weed control in corn was affected by the time of day that herbicides were applied. Weed control following the application of six POST herbicides (atrazine, bromoxynil, dicamba/diflufenzopyr, glyphosate, glufosinate, and nicosulfuron) at 06:00, 09:00, 12:00, 15:00, 18:00, 21:00, and 24:00 h was assessed. For many weed species herbicide efficacy was reduced when applications were made at 06:00, 21:00, and 24:00 h. Velvetleaf was the most sensitive to the time of day effect, followed by common ragweed, common lambsquarters, and redroot pigweed. Annual grasses were not as sensitive to application timing; however, control of barnyardgrass and green foxtail was reduced in some environments at 06:00 h and after 21:00 h. Only in the most severe cases was the grain yield of corn reduced due to decreased weed control. Daily changes in air temperature, relative humidity, and light intensity that cause species-specific physiological changes may account for the variation in weed control throughout the day. The results of this research suggest that there is a strong species-specific influence of ambient air temperature, light intensity, and leaf orientation on the efficacy of POST herbicides. These results should aid growers in applying herbicides when they are most efficacious, thus reducing costs associated with reduced efficacy.

scholarly journals Badania możliwości stosowania norflurazonu do zwalczania Agropyron repens L. Część I. Wpływ norflurazonu na zawartość chlorofilu i karotenu w perzu rozgłogowym [Effect of Norflurazon in weed control. P. I. Influence of Narflurazon on pigment's content in Agropyrcn repens L.]

2015 ◽  
Vol 30 (1) ◽  
pp. 135-150
Author(s):  
Stanisław Karczmarczyk ◽  
Irena Zbieć
Keyword(s):  
Light Intensity ◽  
Chlorophyll Content ◽  
Weed Control ◽  
High Light Intensity ◽  
High Light ◽  
Low Light ◽  
Content Development ◽  
Higher Doses ◽  
Agropyron Repens

The influence of Narflurazon on chlorophyll content, development of <i>Agropron repens</i> L. plants grown under high and low light intensites was studied. Under high light intensity (10 000 lx) both chlorophyll and carotenoides production was markedly reduced, 0.5 ppm and more of Norflurazon bleac ed the platns almost competely. Higher doses of Norflurazon (0.025 ppm and more) significantly inhibited growth and respiration of <i>Agropyron repens</i>.

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