scholarly journals The role of the growth stage of weeds in their response to reduced herbicide doses

2012 ◽  
Vol 64 (4) ◽  
pp. 259-266 ◽  
Author(s):  
Renata Kieloch ◽  
Krzysztof Domaradzki
Keyword(s):  
Growth Stage ◽  
Chenopodium Album ◽  
Growth Stages ◽  
Weed Species ◽  
Stellaria Media ◽  
State Research Institute ◽  
Plant Cultivation ◽  
Weed Growth ◽  
Herbicide Effects ◽  
Anthemis Arvensis

The influence of weed growth stage on the efficacy of selected herbicides applied at reduced doses was investigated under pot experiments at the Institute of Soil Science and Plant Cultivation - State Research Institute in Wrocław. Three weed species were used as tested plants: <i>Anthemis arvensis</i> L., <i>Chenopodium album</i> L. and <i>Stellaria media</i> L., which were sprayed at different growth stages: 2-4, 6-8, and 10-12 leaves. The experiment included the following herbicides: tribenuron-methyl, iodosulfuron methyl sodium + amidosulfuron, and metribuzin + amidosulfuron, used at full doses and reduced by 25 and 50%. Three weeks after treatment, fresh weight of weeds was determined. Weed control was significantly related to weed species, growth stage, type of herbicide and its dose. Among the tested weed species, <i>S. media</i> showed the weakest reaction to the herbicides used and it was only slightly affected by herbicide rate and growth stage. Later herbicide treatments, when the weeds reached the stage of 6-8 and 10-12 leaves, resulted in diversification at the level of herbicide effects and doses.

scholarly journals Effect of Herbicides on the Management of the Invasive Weed Solanum rostratum Dunal (Solanaceae)

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 284
Author(s):  
Jackline Abu-Nassar ◽  
Maor Matzrafi
Keyword(s):  
Growth Stage ◽  
Late Summer ◽  
Early Spring ◽  
Growth Stages ◽  
Weed Species ◽  
Invasive Weed ◽  
Solanum Rostratum ◽  
Stage 4 ◽  
Chemical Solutions ◽  
Late Growth

Solanum rostratum Dunal is an invasive weed species that invaded Israel in the 1950s. The weed appears in several germination flashes, from early spring until late summer. Recently, an increase in its distribution range was observed, alongside the identification of new populations in the northern part of Israel. This study aimed to investigate the efficacy of herbicide application for the control of S. rostratum using two field populations originated from the Golan Heights and the Jezreel Valley. While minor differences in herbicide efficacy were recorded between populations, plant growth stage had a significant effect on herbicide response. Carfentrazone-ethyl was found to be highly effective in controlling plants at both early and late growth stages. Metribuzin, oxadiazon, oxyfluorfen and tembutrione showed reduced efficacy when applied at later growth stage (8–9 cm height), as compared to the application at an early growth stage (4–5 cm height). Tank mixes of oxadiazon and oxyfluorfen with different concentrations of surfactant improved later growth stage plant control. Taken together, our study highlights several herbicides that can improve weed control and may be used as chemical solutions alongside diversified crop rotation options. Thus, they may aid in preventing the spread and further buildup of S. rostratum field populations.

The critical weed-free period in glyphosate-resistant soybean in Ontario is similar to previous estimates using glyphosate-susceptible soybean

2019 ◽  
Vol 99 (4) ◽  
pp. 437-443
Author(s):  
Nader Soltani ◽  
Robert E. Nurse ◽  
Amit J. Jhala ◽  
Peter H. Sikkema
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Yield Loss ◽  
Growth Stages ◽  
Weed Species ◽  
Weed Biomass ◽  
Weed Density ◽  
Weed Interference ◽  
Beginning Of Flowering ◽  
Minimal Reduction

A study consisting of 13 field experiments was conducted during 2014–2016 in southwestern Ontario and southcentral Nebraska (Clay Center) to determine the effect of late-emerging weeds on the yield of glyphosate-resistant soybean. Soybean was maintained weed-free with glyphosate (900 g ae ha−1) up to the VC (cotyledon), V1 (first trifoliate), V2 (second trifoliate), V3 (third trifoliate), V4 (fourth trifoliate), and R1 (beginning of flowering) growth stages, after which weeds were allowed to naturally infest the soybean plots. The total weed density was reduced to 24%, 63%, 67%, 72%, 76%, and 92% in Environment 1 (Exeter, Harrow, and Ridgetown) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 soybean growth stages, respectively. The total weed biomass was reduced by 33%, 82%, 95%, 97%, 97%, and 100% in Environment 1 (Exeter, Harrow, and Ridgetown) and 28%, 100%, 100%, 100%, 100%, and 100% in Environment 2 (Clay Center) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 stages, respectively. The critical weed-free periods for a 2.5%, 5%, and 10% yield loss in soybean were the V1–V2, VC–V1, and VC–V1 soybean stages in Environment 1 (Exeter, Harrow, and Ridgetown) and V2–V3, V2–V3, and V1–V2 soybean stages in Environment 2 (Clay Center), respectively. For the weed species evaluated, there was a minimal reduction in weed biomass (5% or less) when soybean was maintained weed-free beyond the V3 soybean growth stage. These results shows that soybean must be maintained weed-free up to the V3 growth stage to minimize yield loss due to weed interference.

Weed Control Efficacy and Pinto Bean (Phaseolus vulgaris) Tolerance to Early Season Mechanical Weeding

1995 ◽  
Vol 9 (3) ◽  
pp. 531-534 ◽  
Author(s):  
Mark J. Vangessel ◽  
Lori J. Wiles ◽  
Edward E. Schweizer ◽  
Phil Westra
Keyword(s):  
Phaseolus Vulgaris ◽  
Weed Control ◽  
Weed Management ◽  
Seed Weight ◽  
Growth Stage ◽  
Integrated Approach ◽  
Growth Stages ◽  
Weed Species ◽  
Control Efficacy ◽  
Pinto Bean

An integrated approach to weed management in pinto bean is needed since available herbicides seldom adequately control all weed species present in a field. A two-year study was conducted to assess weed control efficacy and pinto bean tolerance to mechanical weeding from a rotary hoe or flex-tine harrow at crook, unifoliolate, and trifoliolate stages of bean development. Weed control was similar for both implements and all timings in 1993. In 1994, mechanical weeding at trifoliolate and both crook and trifoliolate stages controlled more weeds than at other growth stages, regardless of type of implement. Using the flex-tine harrow reduced pinto bean stand, but results based on growth stage were not consistent each year. Damage to pinto bean hypocotyls and stems was observed with the flex-tine harrow used at both crook and trifoliolate stages in 1994. Rotary hoeing did not reduce pinto bean stand or cause injury. Yield and seed weight did not differ among treatments in either year.

scholarly journals Medicinal plants in segetal communities of the Kałuszyńska Upland

2010 ◽  
Vol 61 (1) ◽  
pp. 105-114
Author(s):  
Teresa Skrajna
Keyword(s):  
Medicinal Plants ◽  
Chenopodium Album ◽  
Vascular Plant ◽  
Ground Cover ◽  
Common Species ◽  
Life Forms ◽  
Convolvulus Arvensis ◽  
Stellaria Media ◽  
Anthemis Arvensis ◽  
Segetal Communities

Medicinal plants in segetal communities of the Kałuszyńska Upland The herbal flora of agrocenoses of the Kałuszyńska Upland includes 137 vascular plant species. Apophytes (91species-66,4%) prevail over anthropophytes (46 species-33,6 %). Meadow (32 species), waterside (20 species) and forest apophytes (17 species) were the most numerous. Short-lived plants (71 species) prevail over perennials (66 species) in the analysed flora. Therophytes (65 species) and hemicryptophytes (48 species) were the dominant life forms. Very rare, rare and quite rare species were the most frequent in the flora of the Kałuszyńska Upland. They build up over 63% of the total number of species. The share of common and very common species was about 8%. Some of them, e.g, Equisetum arvense, Chenopodium album, Viola arvensis, Anthemis arvensis, Centaurea cyanus, Cirsium arvense, Elymus repens Convolvulus arvensis, Capsella bursapastoris and Stellaria media were noted with a high ground cover. The occurrence of species rare in the region and in Poland among recorded medicinal plants, e.g., Camelina microcarpa sp. sylvestris, Hypericum humifusum, Consolida regalis, Asperugo procumbens and Herniaria glabra is especially noteworthy.

Weed seed contamination in white clover seedlots

1990 ◽  
pp. 99-102
Author(s):  
J.S. Rowarth ◽  
A.A. Johnson ◽  
P.T.P. Clifford ◽  
M.P. Rolston
Keyword(s):  
White Clover ◽  
Chenopodium Album ◽  
Cirsium Arvense ◽  
Weed Seed ◽  
Weed Species ◽  
Stellaria Media ◽  
Seed Testing ◽  
Rumex Acetosella ◽  
Weed Seeds ◽  
Californian Thistle

Weed seeds are the major reason for white clover (Trifolium repens) seedlots being downgraded or rejected from certification. The occurrence of weed species in 537 white clover seedlots tested at the Official Seed Testing Station, Palmerston North, was analysed. The most commonly occurring species were field madder (Sherardia arvensis), chickweed (Stellaria media), fathen (Chenopodium album), sheep's sorrel (Rumex acetosella) and scarlet pimpernel (Anagaflis arvensis). The percentage occurrence of four specified undesirable weeds including Californian thistle (Cirsium arvense) and dodder (Cuscuta epithymum) are reported, and the implications of seed contamination are discussed. Keywords: white clover, contamination, weed seeds

Growth Stage-Influenced Differential Response of Foxtail and Pigweed Species to Broadcast Flaming

2010 ◽  
Vol 24 (3) ◽  
pp. 319-325 ◽  
Author(s):  
Santiago M. Ulloa ◽  
Avishek Datta ◽  
Stevan Z. Knezevic
Keyword(s):  
Weed Control ◽  
Dry Matter ◽  
Growth Stage ◽  
Field Experiments ◽  
Growth Stages ◽  
Weed Species ◽  
Common Waterhemp ◽  
Species Response ◽  
Redroot Pigweed ◽  
Green Foxtail

Propane flaming could be an effective alternative tool for weed control in organic cropping systems. However, response of major weeds to broadcast flaming must be determined to optimize its proper use. Therefore, field experiments were conducted at the Haskell Agricultural Laboratory, Concord, NE in 2007 and 2008 using six propane doses and four weed species, including green foxtail, yellow foxtail, redroot pigweed, and common waterhemp. Our objective was to describe dose–response curves for weed control with propane. Propane flaming response was evaluated at three different growth stages for each weed species. The propane doses were 0, 12, 31, 50, 68, and 87 kg ha−1. Flaming treatments were applied utilizing a custom-built flamer mounted on a four-wheeler (all-terrain vehicle) moving at a constant speed of 6.4 km h−1. The response of the weed species to propane flaming was evaluated in terms of visual ratings of weed control and dry matter recorded at 14 d after treatment. Weed species response to propane doses were described by log-logistic models relating propane dose to visual ratings or plant dry matter. Overall, response of the weed species to propane flaming varied among species, growth stages, and propane dose. In general, foxtail species were more tolerant than pigweed species. For example, about 85 and 86 kg ha−1were the calculated doses needed for 90% dry matter reduction in five-leaf green foxtail and four-leaf yellow foxtail compared with significantly lower doses of 68 and 46 kg ha−1of propane for five-leaf redroot pigweed and common waterhemp, respectively. About 90% dry matter reduction in pigweed species was achieved with propane dose ranging from 40 to 80 kg ha−1, depending on the growth stage when flaming was conducted. A similar dose of 40 to 60 kg ha−1provided 80% reduction in dry matter for both foxtail species when flaming was done at their vegetative growth stage. However, none of the doses we tested could provide 90% dry matter reduction in foxtail species at flowering stage. It is important to note that foxtail species started regrowing 2 to 3 wk after flaming. Broadcast flaming has potential for control or suppression of weeds in organic farming.

scholarly journals Response of Annual Weeds to Glyphosate: Evaluation and Optimization of Application Rate Based on Fecundity-Avoidance Biomass Threshold Criterion

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 851
Author(s):  
Eduardo S Leguizamon ◽  
German Ferrari ◽  
Martin M Williams ◽  
Nilda R Burgos ◽  
Ilias Travlos ◽  
...  
Keyword(s):  
Chenopodium Album ◽  
Application Rate ◽  
Growth Stages ◽  
Weed Species ◽  
Weed Biomass ◽  
Evaluation Procedures ◽  
Potting Medium ◽  
Threshold Criterion ◽  
Rate Optimization ◽  
Annual Weeds

The increased availability and high adoption rate of glyphosate-tolerant crops have selected for several glyphosate-resistant weed species. The response of representative weed species to glyphosate was assessed to provide insights and tools for optimizing glyphosate use for economic, agronomic and environmental reasons. Anoda cristata, Chenopodium album, Digitaria sanguinalis, Eleusine indica and Portulaca oleracea were grown outdoors in pots containing commercial potting medium. An increasing dose of glyphosate was applied to these species at three growth stages. Weed response was evaluated visually compared to the nontreated control and shoot dry weights were recorded. Fecundity was also determined. Based on visual evaluations, the dose of glyphosate required to attain 90% control of the species tested exhibited an application rate margin up to 28.5-fold compared to recommended rate, denoting a potential for rate optimization. Except for A. cristata, the recommended dose of glyphosate could be reduced by 30%–60% and still achieve 90% or greater control. The order of species sensitivity, based on effective dose 50 (ED50 )values, was E. indica > C. album > D. sanguinalis > P. oleracea > A. cristata. The ratio of ED90/ED50 was constant, indicating that increasing the glyphosate dose 8.7-fold would reduce weed biomass 1.8-fold. In most cases, the fecundity-avoidance biomass threshold (i.e., the maximum allowable weed biomass for herbicide application in order to prevent weed seed production and dispersal) for glyphosate was below the ED90 value. Complimentary measures such as fecundity-avoidance biomass threshold will improve herbicide evaluation procedures and preserve the effectiveness of herbicides, including glyphosate, on sensitive species, an important issue particularly when action to reduce herbicide resistance development is highly required.

scholarly journals Weed flora and weed management of field peas in Finland

2008 ◽  
Vol 14 (2) ◽  
pp. 189 ◽  
Author(s):  
J. SALONEN ◽  
T. HYVÖNEN ◽  
H. JALLI
Keyword(s):  
Weed Management ◽  
Chenopodium Album ◽  
Good Control ◽  
Organic Production ◽  
Grass Species ◽  
Weed Species ◽  
Stellaria Media ◽  
Cropping Practices ◽  
Weed Flora ◽  
Crop Stand

The composition of the weed flora of dry pea (Pisum sativum L.) fields and cropping practices were investigated in southwestern Finland. Surveys were done in 2002–2003 in 119 conventionally cropped fields and 64 fields under organic cropping. Herbicides were applied to 92% of conventionally cropped fields where they provided relatively good control but were costly. Weeds were controlled mechanically only in five fields under organic production. A total of 76 weed species were recorded, of which 29 exceeded the 10% frequency level of occurrence. The average number of weed species per field was 10 under conventional cropping and 18 under organic cropping. The most frequent weed species in both cropping practices were Chenopodium album, Stellaria media and Viola arvensis. Elymus repens was the most frequent grass species. The difference in species composition under conventional and organic cropping was detected with Redundancy Analysis. Under conventional cropping, features of crop stand and weed control explained 38.7% and 37.6% of the variation respectively. Under organic cropping the age of crop stand and field location (y co-ordinate) respectively explained best the variation. Weeds could be efficiently managed with herbicides under conventional cropping, but they represented a significant problem for organic production. Mixed cultivation of pea with cereals is recommended, particularly for organic cropping, as it favours crop competition against weeds.;

scholarly journals Selectivity of Propane Flamer as a Means of Weed Control

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 820C-820 ◽  
Author(s):  
G.D. Leroux ◽  
J. Douheret ◽  
M. Lanouette ◽  
M. Martel
Keyword(s):  
Weed Control ◽  
Plant Protection ◽  
Chenopodium Album ◽  
Amaranthus Retroflexus ◽  
Threshold Temperature ◽  
Growth Stages ◽  
Weed Species ◽  
Higher Temperature ◽  
And Control ◽  
Brassica Kaber

With growing public concern about environmental quality, farmers must turn to new plant protection alternatives that minimize the use of agrochemicals. Flaming has been practiced for several years as a means of weed control in noncropped areas (railroad, ditches, etc.), but its selectivity toward crops has yet to be defined. Experiments were conducted in the ICG-Propane laboratory at Laval Univ. to determine the temperature needed to kill weeds and the temperature that corn could tolerate. Four weed species were studied: Amaranthus retroflexus, Brassica kaber, Chenopodium album, and Setaria viridis and each species was tested at three growth stages: 0–2, 4–6, and >8 leaves. Corn tolerance was tested at four growth stages: coleoptile, 0–2, 4–6, >8 leaves. All plants were grown in the green-house and were submitted to different combinations of operation speeds and of propane pressures, giving 10 temperature intensities ranging from 110 to 390C. The response of each species was evaluated by measuring its height and dry biomass 2 weeks after treatment. The threshold temperature for corn was below 200C; above this temperature, significant corn injury occurred at all growth stages tested. The corn growth stages most tolerant to heat were coleoptile and >8 leaves. While the most sensitive was 4–6 leaves. All weeds tested were sensitive to heat at 0–2 leaf stage. Amaranthus retroflexus and Chenopodium album were controlled until six leaves with temperatures that were not harmful to corn. Weeds with more than eight leaves needed higher temperature, and control rarely reached 60%. Flaming could be a selective method of weed control if operated at a temperature of 170C. Selectivity can be increased by creating a growth differential between corn and weeds.

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