scholarly journals Impact of Application Temperature on Broadleaf Herbicide Efficacy

2016 ◽  
Vol 34 (4) ◽  
pp. 123-130
Author(s):  
Jeffrey Derr ◽  
Thomas Serensits
Keyword(s):  
Weed Control ◽  
Air Temperature ◽  
Warm Temperature ◽  
Weed Species ◽  
Stellaria Media ◽  
Cold Temperatures ◽  
Cold Air ◽  
Time Of Application ◽  
Air Temperatures ◽  
Temperature Applications

Cold air temperatures at the time of herbicide application are generally thought to decrease efficacy of systemic herbicides. Contact herbicides such as carfentrazone and sulfentrazone combined with systemic herbicides may provide an increased level of weed control when applied at cold air temperatures compared to products containing only systemic ones. Identical herbicide treatments were made at air temperatures of approximately 7 C (45 F) and 18 C (65 F) in four different trials. Control of ivyleaf speedwell, common chickweed, henbit, purple deadnettle, and white clover was evaluated. In general, warm temperature applications initially provided better weed control during the first week after treatment (WAT). By 2 to 3 WAT though, air temperature at the time of application generally did not affect overall weed control. In study 1, at 56 days after treatment (DAT) regardless of air temperature at application, all tested herbicides provided 86% or greater control of ivyleaf speedwell (Veronica hederifolia L.), and 98% or greater control of henbit (Lamium amplexicaule L.), with the exception of Trimec Classic, which did not provide acceptable control of henbit. Common chickweed (Stellaria media L.) control with combination treatments containing carfentrazone or sulfentrazone was similar at both temperature regimes, with control of 95% or greater, averaged across application air temperature. In study 2, after higher initial control with warm temperature treatments during the first WAT, Powerzone and Speedzone provided the highest level of control of ivyleaf speedwell and purple deadnettle at 35 DAT with no difference noted between air temperatures at application. Control of ivyleaf speedwell and purple deadnettle (Lamium purpureum L.) with Powerzone was 85 and 82%, respectively, averaged across temperature applications, while Speedzone controlled these two weed species 88 and 92%, respectively. In general, herbicides evaluated provided similar weed control at approximately 50 DAT when applied at warm or cold temperatures. Only for common chickweed control in trial 3 was there a significant interaction between temperature and herbicide treatment when evaluated 50 DAT. In that study, Speedzone and Trimec Classic gave greater control at warm compared to cold temperature application. Herbicides containing carfentrazone plus ester forms of 2,4-D or MCPA provided the highest levels of control.

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 Longevities of Adult Chironomidae (Diptera) from Two Streams in Iceland

2021 ◽  
Author(s):  
Corrie Nyquist ◽  
Gísli Már Gíslason ◽  
Bruce Vondracek ◽  
Leonard Charles Ferrington
Keyword(s):  
Climate Change ◽  
Incubation Temperature ◽  
The Arctic ◽  
Adult Longevity ◽  
Geothermal Area ◽  
Cold Temperatures ◽  
Cold Air ◽  
Change Models ◽  
Air Temperatures ◽  
Thermal Regimes

Mean annual air temperatures are predicted to increase by several degrees in the Arctic. This increase in temperature will likely impact organisms adapted to current conditions. Studies of longevities of winter-active Chironomidae from cold, groundwater-fed streams in Minnesota demonstrate that winter-emerging species are long-lived as adults when incubated at cold or sub-freezing air temperatures post emergence. It is unknown if this holds for species emerging in sub-arctic latitudes during warm months, or if warm air temperatures affect the adults of species emerging from cold and geothermally heated streams. The goal of this study was to determine the effects of exposure to air temperatures predicted by climate change models on the longevities of Chironomidae emerging from both cold and geothermally heated larval environments. Chironomidae were trapped at emergence from two groundwater-fed streams with contrasting (warm and cold) thermal regimes at the Hengladalir valleys in the Hengill alpine geothermal area in southwestern Iceland over 4 days in July 2018. Adults (N=102) were randomly divided into two treatments and incubated at either 20°C or 6°C for 28-32 days to determine influence of source stream and incubation temperature on adult longevity. These temperatures were selected to simulate current and predicted water and air temperatures that adult chironomids are likely to be exposed to with climate change. Adults incubated at 6°C survived longer than adults incubated at 20°C irrespective of source stream. All adults incubated at 20°C died within 1-5 days post-emergence. Longevities of taxa incubated at 6°C ranged from 13 to more than 32 days. Species of Diamesa exhibited the greatest longevities, with 41.7% surviving more than 28-32 days post-emergence at 6°C. We were unable to determine maximum longevity for Diamesa within the 6°C treatment because surviving adults had to be sacrificed at the termination of the experiment on day 32. However, the minimum longevity we report is similar to longevities determined for other Diamesa species and indicates that Diamesa species in Iceland are also long-lived under cold air temperatures. We suggest there may be a difference in longevity between sex, with females living longer than males at cold temperatures. By contrast, we found that both sexes of Diamesa and all other chironomid taxa that we tested are susceptible to warm air temperatures regardless of stream of origin. Therefore, warming climatic temperatures could potentially lead to shortened adult lifespans for these sub-arctic taxa. 

Biologically effective dose of glyphosate as influenced by weed size in corn

2016 ◽  
Vol 96 (3) ◽  
pp. 455-460 ◽  
Author(s):  
Nader Soltani ◽  
Robert E. Nurse ◽  
Peter H. Sikkema
Keyword(s):  
Effective Dose ◽  
Weed Control ◽  
Field Trials ◽  
Biologically Effective Dose ◽  
Limited Information ◽  
Weed Species ◽  
Common Ragweed ◽  
Time Of Application ◽  
Green Foxtail ◽  
Lamb’S Quarters

There is limited information on the effect of weed size at the time of application on glyphosate efficacy in Ontario. Eleven field trials were conducted over a 3 yr period (2010–2012) in Ontario to determine the biologically effective dose of glyphosate applied postemergence (POST) in corn at doses of 112.5–1350 g acid equivalent (a.e.) ha−1 for the control of various grass and broadleaved weed species when the weeds were 10, 20 or 30 cm in height. The GR90 for redroot pigweed, common ragweed, common lamb’s-quarters, barnyardgrass, and green foxtail were 353, 630, 621, 763, and <112.5 g a.e. ha−1 when applied at 10 cm weed height, 235, 201, 906, 868, and 296 g a.e. ha−1 when applied at 20 cm weed height, and 792, >1350, >1350, 912, and 675 g a.e. ha−1 when applied at 30 cm weed height, respectively. Corn yields were maximized when glyphosate was applied to weeds that were up to 10 cm in height, but was reduced with later glyphosate application timings. The results of this study reinforce the importance of early POST weed control in corn.

scholarly journals Efficacy of the herbicide GF-2581 (penoxsulam + florasulam) against broadleaf weeds in olives

2014 ◽  
Vol 60 (No. 12) ◽  
pp. 574-579 ◽  
Author(s):  
Travlos IS ◽  
M. Lysandrou ◽  
V. Apostolidis
Keyword(s):  
Weed Control ◽  
Management Strategies ◽  
Growing Season ◽  
Field Trials ◽  
Conyza Canadensis ◽  
Weed Species ◽  
Stellaria Media ◽  
Excellent Control ◽  
Control Management

Effective weed control in perennial crops is a challenge due to the limited availability of registered herbicides and herbicide resistance. The objective of the study was to evaluate the efficacy of the herbicide GF-2581 (penoxsulam + florasulam) on broadleaf weeds in comparison with other commonly used herbicides. Field trials were conducted in olives, in Etoloakarnania (Agrinio region) for two years (2012 and 2013). Efficacy assessments were made at 30, 60, 90 and 120 days after treatment. The GF-2581 formulation provided excellent control of a broad spectrum of broadleaf weed species. The long-term control of Sonchus oleraceous, Conyza canadensis and Stellaria media, provided by GF-2581 during the growing season was significantly greater than that using flumioxazin. When combined with glyphosate or diquat, the level of control of these three weeds was improved. The GF-2581 agent applied pre-emergence followed 14 days later by application of glyphosate provided 100% control in 2012. Lower efficacy levels were observed in 2013 and may have been the result of higher rainfall when compared to 2012. GF-2581 is an effective herbicide product to control broadleaf weeds, as a part of integrated weed control management strategies in olives.

The Effect of Time of Day on the Activity of Postemergence Soybean Herbicides

2013 ◽  
Vol 27 (4) ◽  
pp. 690-695 ◽  
Author(s):  
Gregory J. Stopps ◽  
Robert E. Nurse ◽  
Peter H. Sikkema
Keyword(s):  
Weed Control ◽  
Yield Loss ◽  
Early Morning ◽  
Field Trials ◽  
Time Of Day ◽  
Weed Species ◽  
Time Of Application ◽  
Late Evening ◽  
Chlorimuron Ethyl ◽  
Herbicide Activity

The effect of time of day (TOD) on the activity of six common POST herbicides was investigated in field trials from 2007 to 2009 at two locations in southwestern Ontario. Percentage weed control was assessed following application of bentazon, chlorimuron-ethyl, fomesafen, glyphosate, imazethapyr, or quizalofop-p-ethyl applied at 3-h intervals from 6:00 A.M. to midnight, when weeds averaged 15 cm tall. The effect of time of day varied with weed species, but weed control was generally reduced when herbicides were applied at 6:00 A.M., 9:00 P.M., and midnight. Herbicide activity on velvetleaf was most frequently reduced, especially for chlorimuron-ethyl, glyphosate, and imazethapyr. Control of common ragweed with glyphosate and imazethapyr was also affected by the timing of application, and pigweed species only showed an effect with glyphosate. Variation in temperature, relative humidity, and dew presence/absence at different times of the day, as well as morphological/physiological characteristics such as weed size at time of application and diurnal leaf movement in response to light intensity, may account for the variation in weed control at different times of the day. Significant soybean yield loss was not observed in this study, but may occur if herbicide efficacy is severely reduced by application at inappropriate times of day. These results provide valuable information for growers, and suggest that POST herbicides are most effective when applied midday, rather than in the early morning or late evening.

scholarly journals EFFECTS OF TILLAGE SYSTEMS AND FERTILIZATION LEVEL ON THE WEEDINESS OF WINTER WHEAT

AGROFOR ◽  
2018 ◽  
Vol 2 (2) ◽  
Author(s):  
Dušan KOVAČEVIĆ ◽  
Snežana OLJAČA ◽  
Željko DOLIJANOVIĆ ◽  
Vesna MILIĆ ◽  
Nemanja GRŠIĆ ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Weed Control ◽  
Floristic Composition ◽  
Conventional Tillage ◽  
Weed Species ◽  
Stellaria Media ◽  
Tillage Systems ◽  
Fresh Biomass ◽  
Tillage System ◽  
Fertilization Level

This paper deals with results of the effects of three tillage systems and differentnitrogen fertilizer level on floristic composition of weed community in winterwheat in investigated period on the chernozem-luvic soil type. The trial was carriedout on the estate experimental field of the Faculty of Agriculture - Zemun"Radmilovac" near Belgrade in Serbia. Tillage systems and fertilization withnitrogen fertilizers have a big influence on weed control and floristic composition,number of species and individuals and biomass of weeds in winter wheat. Theweed community in winter wheat crops was composed of 14 weed species in bothyear of investigation, respectively, with dominancy of terophytes. The obtainedresults showed that the dominant weed species were Avena fatua L., Papaverrhoeas L., Sinapis arvensis L. and Stellaria media (L.) Vill. from annuels and.Convolvulus arvensis L. from perennials prevailed in the weed community inwinter wheat crops.Conventional tillage system with nitrogen level in top dressing120 kg ha-1 had better effect in weed control than both of both investigatedconservation tillage systems (MTS and NTS) had. However, mulch tillage has notlagged behind the conventional tillage increased total weed number of individualsannual and perennial species especially fresh biomass. No-tillage system makesweed control difficult.

Influence of Tillage and Herbicides on Weed Control in a Wheat (Triticum aestivum)–Soybean (Glycine max) Rotation

Weed Science ◽  
1986 ◽  
Vol 34 (4) ◽  
pp. 590-594 ◽  
Author(s):  
Henry P. Wilson ◽  
Martin P. Mascianica ◽  
Thomas E. Hines ◽  
Ronald F. Walden
Keyword(s):  
Triticum Aestivum ◽  
Glycine Max ◽  
Weed Control ◽  
Field Studies ◽  
Conventional Tillage ◽  
Weed Species ◽  
Stellaria Media ◽  
Grain Yields ◽  
No Till ◽  
Anthemis Arvensis

Field studies were conducted for 4 yr to investigate the effects of tillage and herbicide programs on weed control and wheat (Triticum aestivumL. ‘Potomac’ in 1981 and ‘Wheeler’ from 1982 to 1984) grain yields in a wheat-soy bean [Glycine max(L.) Merr.] double-crop rotation. Predominant weed species were common chickweed [Stellaria media(L.) Vill. # STEME], corn chamomile (Anthemis arvensisL. # ANTAR), and annual bluegrass (Poa annuaL. # POAAN) at the onset of research and cheat (Bromus secalinusL. # BROSE) and soft brome (Bromus mollisL. # BROMO) at the conclusion of the study. Control of all species was excellent with conventional tillage and no-till plus nonselective herbicides but was significantly less with no-till without nonselective herbicides and with minimum tillage. After 4 yr, maximum wheat grain yields were significantly higher in conventional- than in minimum- or no-till systems.

scholarly journals Air temperatures in Central Amazonia. III. - Vertical Temperature Distribution on a Clearcut Area and in a Secondary Forest near Manaus (Cold Front Conditions July 10 th. 1969)()

1972 ◽  
Vol 2 (3) ◽  
pp. 25-29 ◽  
Author(s):  
W. L. F. Brinkmann ◽  
M. N. Góes Ribeiro
Keyword(s):  
Air Temperature ◽  
Cold Front ◽  
Secondary Forest ◽  
Cold Air ◽  
Air Temperatures ◽  
Canopy Area ◽  
Yearly Average ◽  
Central Amazonia ◽  
Temperature Records ◽  
Vertical Temperature Distribution

Abstract Air temperatures under cold front conditions were recorded on July 10th 1969 inside and outside a secondary forest at Ducke Forest Reserve Air temperatures were measured at 2 towers and 8 corresponding levels ranging from 10 cm to 900 cm height. The absolute daily minimum air temperature recorded was 11.0°C, which is exceptionally low for Central Amazonia and 16.0°C below the yearly average air temperature at Manaus measured over a 45-year period of temperature records. The maximum 30-min range of air temperature was observed in the clearing (8.1°C), 7 meters above the ground. The strongest impact of air temperatures in the forest stand was recorded in the canopy area and in the ground stratum due to the formation of cold air cells and cold air sinks. The temperature profiles inside and outside the secondary forest at Ducke Forest Preserve during cold front conditions did not conform with the established temperature patterns in a tropical environment.

Winter Annual Weed Control in Dormant Bermudagrass Turf

Weed Science ◽  
1977 ◽  
Vol 25 (2) ◽  
pp. 145-150 ◽  
Author(s):  
B.J. Johnson
Keyword(s):  
Weed Control ◽  
Propionic Acid ◽  
Cynodon Dactylon ◽  
Single Treatment ◽  
Weed Species ◽  
Stellaria Media ◽  
Herbicide Treatments ◽  
Excellent Control ◽  
Winter Annual

Control of annual broadleaf winter weeds in dormant bermudagrass [Cynodon dactylon(L.) Pers. ‘Common’] by a variety of herbicides was examined. Nearly all treatments allowed good to excellent control of spur weed (Soliva sessilisP. and K.). Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] was the only tested herbicide that controlled all weed species consistently with a single treatment. Bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4) 3H-one 2,2-dioxide] applied alone as single or repeated treatments controlled spur weed, parsley-piert (Alchemilla microcorpaBoissier Reuter), and chickweed [Stellaria media(L.) Cyrillo], but a combination of bentazon and silvex [2-(2,4,5-trichlorophenoxy)propionic acid] were needed for acceptable control of henbit (Lamium amplexicauleL.) and corn speedwell (Veronica arvensisL.). None of the herbicide treatments affected green-up of bermudagrass the following spring.

The Potential Use of Vinegar and a Clove Oil Herbicide for Weed Control in Sweet Corn, Potato, and Onion

2009 ◽  
Vol 23 (1) ◽  
pp. 120-128 ◽  
Author(s):  
G. J. Evans ◽  
R. R. Bellinder
Keyword(s):  
Weed Control ◽  
Sweet Corn ◽  
Field Trials ◽  
Clove Oil ◽  
Weed Species ◽  
Marketable Yield ◽  
Yield Data ◽  
Application Timing ◽  
Time Of Application ◽  
Potential Use

Natural products might provide an organic means of weed control. Our objective was to evaluate the potential use of vinegar and a clove-oil product with regard to how volume, concentration, and application timing affect weed control and crop response. Treatments included broadcast applications of 200- and 300-grain vinegar at 318 liters per hectare (L/ha), 150- and 200-grain vinegar at 636 L/ha, a 3.4% v/v clove oil mixture in water (318 L/ha), and a 1.7% clove oil mixture in 200-grain vinegar (318 L/ha). Field trials were conducted in sweet corn, onion, and potato. Weed control, weed biomass, crop injury, and yield data were collected. Corn treated at 15 and at 30 to 45 cm was initially burned and stunted by these products. By 4 wk after application much of the initial injury was outgrown. Late applications significantly reduced yields of early-maturing sweet corn ‘Trinity’. With the exception of the 200-grain vinegar (318 L/ha) treatment, early applications to sweet corn ‘Avalon’ did not reduce marketable yield. Two hundred-grain vinegar (636 L/ha) applied to pre-emergence–flag stage onion reduced the duration of the first handweeding by 59 to 67%. All treatments reduced onion yields when treated at the 2-leaf stage. Potato treated early (2 to 10 cm) and late (30 cm) were injured by all vinegar treatments 59 to 83%, 1 d after treatment (DAT). Potato yield losses were insignificant with applications of 3.4% clove oil and with some low-volume (318 L/ha) vinegar treatments. Product efficacy was dependent on the weed species and their size at the time of application. Weed control was greatest (83%, 1 DAT) with 200-grain vinegar (636 L/ha). Broadcast applications of vinegar and clove oil have potential for use on young, actively growing sweet corn, onion, and potato.

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