Predicting weed emergence for eight annual species in the northeastern United States

Weed Science ◽  
2004 ◽  
Vol 52 (6) ◽  
pp. 913-919 ◽  
Author(s):  
Matthew W. Myers ◽  
William S. Curran ◽  
Mark J. VanGessel ◽  
Dennis D. Calvin ◽  
David A. Mortensen ◽  
...  

A 2-yr experiment assessed the potential for using soil degree days (DD) to predict cumulative weed emergence. Emerged weeds, by species, were monitored every 2 wk in undisturbed plots. Soil DD were calculated at each location using a base temperature of 9 C. Weed emergence was fit with logistic regression for common ragweed, common lambsquarters, velvetleaf, giant foxtail, yellow foxtail, large crabgrass, smooth pigweed, and eastern black nightshade. Coefficients of determination for the logistic models fit to the field data ranged between 0.90 and 0.95 for the eight weed species. Common ragweed and common lambsquarters were among the earliest species to emerge, reaching 10% emergence before 150 DD. Velvetleaf, giant foxtail, and yellow foxtail were next, completing 10% emergence by 180 DD. The last weeds to emerge were large crabgrass, smooth pigweed, and eastern black nightshade, which emerged after 280 DD. The developed models were verified by predicting cumulative weed emergence in adjacent plots. The coefficients of determination for the model verification plots ranged from 0.66 to 0.99 and averaged 0.90 across all eight weed species. These results suggest that soil DD are good predictors for weed emergence. Forecasting weed emergence will help growers make better crop and weed management decisions.

2005 ◽  
Vol 19 (2) ◽  
pp. 274-282 ◽  
Author(s):  
Matthew W. Myers ◽  
William S. Curran ◽  
Mark J. Vangessel ◽  
Brad A. Majek ◽  
David A. Mortensen ◽  
...  

A 2-yr experiment evaluated the effect of spring soil disturbance on the periodicity of weed emergence. At four locations across the northeastern United States, emerged weeds, by species, were monitored every 2 wk in both undisturbed plots and plots tilled in the spring with a rotary cultivator. Eight weed species including large crabgrass, giant and yellow foxtail, common lambsquarters, smooth pigweed, eastern black nightshade, common ragweed, and velvetleaf occurred at three or more site-years. Spring soil disturbance either had no effect or reduced total seedling emergence compared with undisturbed soils. Total seedling emergence for large crabgrass, giant foxtail, smooth pigweed, and common ragweed were on average, 1.4 to 2.6 times less with spring soil disturbance, whereas eastern black nightshade and velvetleaf were mostly unaffected by the soil disturbance. The influence of soil disturbance on yellow foxtail and common lambsquarters emergence varied between seasons and locations. Although the total number of emerged seedlings was often affected by the soil disturbance, with the exception of yellow foxtail and common ragweed, the periodicity of emergence was similar across disturbed and undisturbed treatments.


1998 ◽  
Vol 12 (2) ◽  
pp. 293-299 ◽  
Author(s):  
Kelly A. Nelson ◽  
Karen A. Renner

Field and greenhouse experiments were conducted to evaluate postemergence (POST) soybean injury and weed control with CGA-277476 and cloransulam-methyl alone and in tank mixtures. In the field, visible soybean injury was 12 to 14% from CGA-277476 and 9 to 13% from cloransulam-methyl 7 d after treatment. Tank mixtures of either herbicide with acifluorfen or acifluorfen plus thifensulfuron were more injurious than CGA-277476 or cloransulam-methyl applied alone. Both CGA-277476 and cloransulam-methyl reduced velvetleaf dry weight 82%, and cloransulam-methyl reduced common ragweed dry weight 92%. Neither herbicide adequately controlled common lambsquarters, redroot pigweed, nor eastern black nightshade. The addition of acifluorfen to the spray solution improved common ragweed, common lambsquarters, redroot pigweed, and eastern black nightshade control with CGA-277476 and improved common lambsquarters, redroot pigweed, and eastern black nightshade control with cloransulam-methyl. Tank mixing thifensulfuron with CGA-277476 or cloransulam-methyl increased common lambsquarters and redroot pigweed control. In the greenhouse, CGA-277476 at 20 g ai/ha reduced velvetleaf dry weight 98%, and 79 g/ha was required to reduce common ragweed dry weight 93%. Cloransulam-methyl at 4.4 g ai/ha reduced velvetleaf dry weight 98% and common ragweed dry weight 94% at 8.8 g/ha. Chlorimuron reduced yellow nutsedge dry weight more than CGA-277476 or cloransulam-methyl. Antagonism of POST graminicide activity by CGA-277476 was grass species and graminicide related. CGA-277476 reduced giant foxtail control by clethodim but not by quizalofop. Cloransulam-methyl tank mixed with clethodim or quizalofop controlled giant foxtail.


1999 ◽  
Vol 13 (3) ◽  
pp. 542-547 ◽  
Author(s):  
Brent E. Tharp ◽  
Oliver Schabenberger ◽  
James J. Kells

The recent introduction of glufosinate-resistant and glyphosate-resistant crops provides growers with new options for weed management. Information is needed to compare the effectiveness of glufosinate and glyphosate on annual weeds. Greenhouse trials were conducted to determine the response of barnyardgrass (Echinochloa crus-galli), common lambsquarters (Chenopodium album), common ragweed (Ambrosia artemisiifolia), fall panicum (Panicum dichotomiflorum), giant foxtail (Setaria faberi), large crabgrass (Digitaria sanguinalis), and velvetleaf (Abutilon theophrasti) to glufosinate and glyphosate. The response of velvetleaf and common lambsquarters was investigated at multiple stages of growth. Glufosinate and glyphosate were applied to each weed species at logarithmically incremented rates. The glufosinate and glyphosate rates that provided a 50% reduction in aboveground weed biomass, commonly referred to as GR50values, were compared using nonlinear regression techniques. Barnyardgrass, common ragweed, fall panicum, giant foxtail, and large crabgrass responded similarly to glufosinate and glyphosate. Common lambsquarters 4 to 8 cm in height was more sensitive to glufosinate than glyphosate. In contrast, 15- to 20-cm tall-velvetleaf was more sensitive to glyphosate than glufosinate.


2006 ◽  
Vol 20 (3) ◽  
pp. 605-611 ◽  
Author(s):  
Cory M. Whaley ◽  
Gregory R. Armel ◽  
Henry P. Wilson ◽  
Thomas E. Hines

Field experiments were conducted in 2002 and 2003 to evaluate total POST weed control in corn with mixtures of mesotrione, atrazine, and the commercial mixture of nicosulfuron plus rimsulfuron plus atrazine at registered and reduced rates. Treatments were compared with nicosulfuron plus rimsulfuron plus atrazine POST, andS-metolachlor plus atrazine PRE alone and followed by (fb) nicosulfuron plus rimsulfuron plus atrazine POST. All treatments controlled common lambsquarters 8 wk after the postemergence treatments (WAPT). Common ragweed control with POST mesotrione plus nicosulfuron plus rimsulfuron plus atrazine combinations was greater than 89%. Mesotrione plus the registered rate of nicosulfuron plus rimsulfuron plus atrazine POST controlled common ragweed more effectively than the PRE treatment alone. Addition of atrazine to mesotrione improved common ragweed control by at least 38 percentage points over mesotrione alone. Nicosulfuron plus rimsulfuron plus atrazine at the registered rate and in mixtures with mesotrione controlled morningglory species (pitted and ivyleaf morningglory) 89 to 91%. Large crabgrass control varied between 2002 and 2003. In 2002, large crabgrass control was 58 to 76% with all POST treatments, but in 2003, nicosulfuron plus rimsulfuron plus atrazine POST alone controlled large crabgrass greater than 86%. Large crabgrass was more effectively controlled by treatments withS-metolachlor plus atrazine PRE than by the total POST treatments in 2002. Giant foxtail was controlled at least 97% with nicosulfuron plus rimsulfuron plus atrazine treatments.S-metolachlor plus atrazine PRE fb nicosulfuron plus rimsulfuron plus atrazine POST controlled all weed species greater than 85%. Corn yields by total POST treatment combinations of mesotrione plus either rate of nicosulfuron plus rimsulfuron plus atrazine were comparable toS-metolachlor plus atrazine PRE alone or fb nicosulfuron plus rimsulfuron plus atrazine POST.


1998 ◽  
Vol 12 (1) ◽  
pp. 151-156 ◽  
Author(s):  
Ronald F. Krausz ◽  
George Kapusta

Field experiments were conducted in 1994 and 1995 to evaluate weed control in imidazolinone-resistant corn with postemergence applications of imidazolinone and sulfonylurea herbicides. Imazethapyr controlled 100% of redroot pigweed, jimsonweed, and eastern black nightshade. Control of fall panicum with imazethapyr was inconsistent, with control ranging from 42 to 85%. Imazethapyr provided less than 55% control of common lambsquarters and 43% of large crabgrass. Imazethapyr plus either atrazine, 2,4-D, or dicamba increased control of common lambsquarters compared to imazethapyr alone. Fall panicum control was > 95% with nicosufluron. CGA-152005 and MON 12000 did not control eastern black nightshade. In 1995, corn yield was greater with the hand-weeded check compared to all herbicide treatments. The greatest return over herbicide cost with imazethapyr was obtained with imazethapyr plus atrazine. Nicosulfuron plus CGA-152005 provided the greatest return over herbicide cost when averaged across years.


Weed Science ◽  
2009 ◽  
Vol 57 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Joel Felix ◽  
Jerry Ivany ◽  
George O. Kegode ◽  
Doug Doohan

A weed emergence prediction model, WeedCast, was used as a decision aid to schedule potato cultivation with and without herbicides at Wooster, OH, USA; Charlottetown, PE, Canada; and Fargo, ND, USA, from 2001 to 2003. Studies were laid out in a split-plot design with herbicides (±) forming the main plots and cultivation timing as subplots. Cultivation was done at 15, 30, or 60% of predicted weed emergence. Subplots were either left unsprayed or treated with metolachlor + metribuzin at 1.68 + 0.5 kg ai ha−1and only cultivated at predetermined timing. Cultivation timing was based on predicted emergence of common lambsquarters at Wooster and Charlottetown, whereas eastern black nightshade was the indicator weed at Fargo. Weed control for the different cultivation timings varied among sites and years and was consistently better in plots where herbicides were followed by cultivation. Cultivation alone resulted in poor weed control and significantly reduced potato tuber yield compared with those in plots where weed control also included herbicides. Use of herbicides followed by cultivation and hilling increased tuber yield by 4.6, 4.3, and 8.7 t ha−1, when cultivations were done at 15, 30, and 60% of predicted weed emergence, respectively, and 12.2 t ha−1for hilled-only plots. The average potato yield increase at Charlottetown was 9.7, 5.9, 6.9, and 7.4 t ha−1for hilled-only plots and for hilled after cultivations at 15, 30, and 60% of predicted weed emergence with herbicides, respectively. There was no apparent pattern for treatment effects at Fargo, and the potato tuber yields were greatly reduced mainly because of excessive precipitation during potato establishment. Use of WeedCast as a decision-aid tool could be an asset in determining when to do the first and subsequent cultivations. It may work best for growers who use cultivations in potato to remove weeds that were not controlled by herbicides.


Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 327-335 ◽  
Author(s):  
Alex G. Ogg ◽  
Jean H. Dawson

Under irrigated field conditions at Prosser, WA, Russian thistle [Salsola kali(L.) var.tenuifoliaTausch. ♯3SASKR] began to emerge by mid-March each year and usually had completed its emergence by May 1. Common lambsquarters (Chenopodium albumL. ♯ CHEAL) was the next to appear, usually during the third or fourth week of March. Barnyardgrass [Echinochloa crus-galli(L.) Beauv. ♯ ECHCG], redroot pigweed (Amaranthus retroflexusL. ♯ AMARE), hairy nightshade (Solarium sarrachoidesSendt. ♯ SOLSA), black nightshade (5.nigrumL. ♯ SOLNI), eastern black nightshade (S. ptycanthumDun.), and cutleaf nightshade (S. triflorumNutt. ♯ SOLTR) generally began to emerge during the first 2 weeks of April and emergence generally peaked mid-April to mid-May. Russian thistle and cutleaf nightshade had the most restricted emergence patterns, whereas seedlings of common lambsquarters, redroot pigweed, hairy nightshade, and black nightshade emerged each month from April through September. Shallow tillage at monthly intervals increased the overall emergence of common lambsquarters, redroot pigweed, black nightshade, and eastern black nightshade; decreased the emergence of barnyardgrass; and had no effect on the emergence of Russian thistle, cutleaf nightshade, or hairy nightshade.


1996 ◽  
Vol 10 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Darren K. Robinson ◽  
David W. Monks ◽  
Thomas J. Monaco

Field studies were conducted to determine response of ‘Atlantic’ and ‘Fontenot’ potato varieties and eight weed species to rimsulfuron and metribuzin. Rimsulfuron was applied at 9, 18, 27, 35 and 70 g ai/ha and metribuzin at 69, 140, 210, 280 and 560 g ai/ha. Each herbicide was applied PRE or POST alone or in 1:8 combinations of rimsulfuron to metribuzin. Yield of either variety was not reduced by any treatment. Rimsulfuron applied PRE or POST at the suggested field use rate of 35 g/ha controlled smooth pigweed, redroot pigweed, ivyleaf morningglory, and common cocklebur 100%, common lambsquarters 90%, and jimsonweed 60%. Large crabgrass and fall panicum were controlled 92% by rimsulfuron at 35 g/ha. Reduced rates of 9 g/ha rimsulfuron plus 69 g/ha metribuzin, applied PRE or POST, controlled all weeds 100% except jimsonweed, fall panicum, and large crabgrass. For complete control of these weeds, rimsulfuron at 35 g/ha plus metribuzin at 280 g/ha was required.


Weed Science ◽  
1999 ◽  
Vol 47 (1) ◽  
pp. 95-106 ◽  
Author(s):  
Dawit Mulugeta ◽  
Chris M. Boerboom

A better understanding of the influence of various crop and weed management practices on spatiotemporal dynamics of weeds could improve the design of integrated weed management systems. We examined the influence of 18- and 76-cm soybean row spacings on emergence pattern and spatial aggregation of giant foxtail, common lambsquarters, and velvetleaf seedling cohorts. In addition, we characterized the soil seedbank and determined the quantitative and spatial relationship between the seedbank and seedling populations. Viable seeds of about 10 weed species and twice as many species of seedlings were identified in the weed community. Giant foxtail and common lambsquarters were the predominant species in the seedling and seedbank population, respectively, each accounting for 60 to 70% of the total weed species density. Emergence of giant foxtail, common lambsquarters, and velvetleaf depleted 12 to 33%, < 2% and 12 to 49% of the seedbank in the upper 10 cm of the soil profile. Peak time and periodicity of weed emergence was not influenced by soybean row spacing, and peak time of emergence of giant foxtail, common lambsquarters, and velvetleaf occurred 3 to 4, 3 to 6, and 3 to 9 weeks after soybean planting (WAP), respectively. Magnitude of giant foxtail emergence 5, 6, and 9 WAP was 98, 96, and 76% greater in 76- than in 18-cm row soybeans only when the population of 76-cm row soybeans was 57% lower than the 18-cm soybeans in 1997. Giant foxtail and common lambsquarters seeds in the seedbank were aggregated in 1996 and 1997 according to the Taylor power law (TPL) and the negative binomial distribution (NBD). The TPL and the NBD were similar in describing the spatial aggregation of giant foxtail and common lambsquarters but not some velvetleaf seedling cohorts. The spatial aggregation of seedlings varied among cohorts for different weed species and was likely due to species-specific biological characteristics that influence seed dispersal, germination, and seedling emergence. Within a 1.5-ha area, aggregation declined with decreasing density. Within a 24-m2area, the level of aggregation of all weed species decreased as seedling densities increased. These results indicated that soybean row spacing influenced neither weed emergence pattern nor weed spatial aggregation; thus, several management decisions can be similar in 18- and 76-cm row soybeans.


2005 ◽  
Vol 19 (3) ◽  
pp. 744-748 ◽  
Author(s):  
Robert J. Richardson ◽  
Henry P. Wilson ◽  
Gregory R. Armel ◽  
Thomas E. Hines

Field and greenhouse studies were conducted in 2000, 2001, and 2002 to evaluate the response of imidazolinone-resistant (IR) corn and selected weeds to trifloxysulfuron applied postemergence (POST). Treatments included a nontreated control andS-metolachlor applied preemergence at 1,075 g ai/ha followed by (fb) trifloxysulfuron POST at 0, 3.8, 7.5, 11.2, and 15 g ai/ha. IR corn visible injury was less than 6% from field applications of trifloxysulfuron. Visual symptoms were transient, and IR corn yield was not affected by trifloxysulfuron. Common ragweed, common lambsquarters, annual grass species (giant foxtail and large crabgrass), and carpetweed were controlled at least 95% byS-metolachlor fb trifloxysulfuron applications. Morningglory species (ivyleaf morningglory, pitted morningglory, and tall morningglory) were controlled at least 97% in 2000 and greater than 77% in 2001 fromS-metolachlor fb trifloxysulfuron. Jimsonweed was not adequately controlled.S-metolachlor alone controlled annual grass species 90% but did not control the broadleaf weeds that were present. Wheat was planted following IR corn harvest, and non-IR corn was planted the following spring. No visible response was observed to rotational wheat or non-IR corn crops. Rotational non-IR corn yield was not affected by trifloxysulfuron and was not different from the yield of corn treated withS-metolachlor alone. In greenhouse studies, IR corn was injured 10% at 10 d after treatment with 380 g/ha trifloxysulfuron POST, but recovery was rapid. Based upon results, trifloxysulfuron may be used as an herbicide in IR corn, and rotational wheat and non-IR corn may be planted at normal intervals after cotton harvest.


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