scholarly journals Effect of precipitation on the dissipation, efficacy and selectivity of three chloroacetamide herbicides in sunflower

2013 ◽  
Vol 59 (No. 4) ◽  
pp. 175-182 ◽  
Author(s):  
M. Jursík ◽  
M. Kočárek ◽  
K. Hamouzová ◽  
J. Soukup ◽  
V. Venclová
Keyword(s):  
Active Ingredient ◽  
Field Trial ◽  
Chenopodium Album ◽  
Soil Layer ◽  
Growing Season ◽  
Amaranthus Retroflexus ◽  
Low Level ◽  
Small Plot ◽  
Higher Temperature ◽  
The Mean

The aim was to compare the efficacy, selectivity to sunflower and dissipation of three chloracetamide herbicides (acetochlor, metolachlor and pethoxamid) in dependence on precipitation after application. A small plot field trial was carried out with sunflower in Central Bohemia in 2010 and 2011. The remaining concentration of active ingredient in the soil of all studied herbicides was lower in the year with a higher temperature and a low level of total natural precipitation at the beginning of the growing season. Higher leaching of metolachlor and pethoxamid was recorded in irrigated plots. No leaching was found in the case of acetochlor. The highest leaching was found for metolachlor (9.2–25.5% in soil layer 5–10 cm). The highest phytotoxicity was found for acetochlor (9.8%) > pethox-amid (4.6%) > metolachlor (1.8%). The mean phytotoxicity in the irrigated plots was 6.9%, compared with 3.9% in the non-irrigated plots. The efficacy of the tested herbicide was affected by wet conditions. The highest efficacy on Chenopodium album, Amaranthus retroflexus, Echinochloa crus-galli and Solanum physalifolium was recorded after application of acetochlor and irrigation.

scholarly journals Effect of different soil and weather conditions on efficacy, selectivity and dissipation of herbicides in sunflower

2020 ◽  
Vol 66 (No. 9) ◽  
pp. 468-476
Author(s):  
Miroslav Jursík ◽  
Martin Kočárek ◽  
Michaela Kolářová ◽  
Lukáš Tichý
Keyword(s):  
Cation Exchange Capacity ◽  
Chenopodium Album ◽  
Soil Layer ◽  
Weather Conditions ◽  
Growing Season ◽  
Application Rate ◽  
Exchange Capacity ◽  
Vertical Transport ◽  
Application Rates ◽  
High Precipitation

Six sunflower herbicides were tested at two application rates (1N and 2N) on three locations (with different soil types) within three years (2015–2017). Efficacy of the tested herbicides on Chenopodium album increased with an increasing cation exchange capacity (CEC) of the soil. Efficacy of pendimethalin was 95%, flurochloridone and aclonifen 94%, dimethenamid-P 72%, pethoxamid 49% and S-metolachlor 47%. All tested herbicides injured sunflower on sandy soil (Regosol) which had the lowest CEC, especially in wet conditions (phytotoxicity 27% after 1N application rate). The highest phytotoxicity was recorded after the application of dimethenamid-P (19% at 1N and 45% at 2N application rate). Main symptoms of phytotoxicity were leaf deformations and necroses and the damage of growing tips, which led to destruction of some plants. Aclonifen, pethoxamid and S-metolachlor at 1N did not injure sunflower on the soil with the highest CEC (Chernozem) in any of the experimental years. Persistence of tested herbicides was significantly longer in Fluvisol (medium CEC) compared to Regosol and Chernozem. Dimethenamid-P showed the shortest persistence in Regosol and Chernozem. The majority of herbicides was detected in the soil layer 0–5 cm in all tested soils. Vertical transport of herbicides in soil was affected by the herbicide used, soil type and weather conditions. The highest vertical transport was recorded for dimethenamid-P and pethoxamid (4, resp. 6% of applied rate) in Regosol in the growing season with high precipitation.  

scholarly journals Weed Interference Affects Dry Bean Yield and Growth

2012 ◽  
Vol 4 (3) ◽  
pp. 70-75 ◽  
Author(s):  
Hossein GHAMARI ◽  
Goudarz AHMADVAND
Keyword(s):  
Chenopodium Album ◽  
Growing Season ◽  
Amaranthus Retroflexus ◽  
Growth And Yield ◽  
Weed Competition ◽  
Weed Species ◽  
Dry Bean ◽  
Logistic Equations ◽  
Weed Interference ◽  
Minimum Number

Dry bean is one of the most important pulse crops in Iran. Field study was conducted in 2011 to evaluate effects of weed competition from a natural flora on growth and yield of dry bean (Phaseolus vulgaris L.). The treatments consisted of weed infestation and weed removal periods (10, 20, 30, 40 and 50 days) after crop emergence. Control plots kept weed-infested and weed-free throughout growing season. To assess the weed competition effect on crop characteristics, Richards, Gompertz and logistic equations were fitted to the data. The most abundant weed species were Chenopodium album and Amaranthus retroflexus. Increase in duration of weed interference decreased the stem height of dry bean. At the end of the growing season, dry bean was 20 cm taller in season-long weed-free treatment compared to the season-long weed-infested treatment. As the number of days of weed interference increased, a declining trend of LAI and number of pods was observed. The minimum number of pods was obtained in season-long weed-infested treatment (5.01 pods/plant). Weed interference during the whole growing season, caused a 60% reduction in yield. Considering 5% and 10% acceptable yield lost, the critical period of weed competition was determined from 20 to 68 and 23 to 55 days after planting (DAE), respectively.

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.

scholarly journals Present and potential weed infestation of spring cereals in different cropping system

2013 ◽  
Vol 54 (1) ◽  
pp. 175-190
Author(s):  
Andrzej Wesołowski ◽  
Andrzej Woźniak
Keyword(s):  
Crop Rotation ◽  
Chenopodium Album ◽  
Soil Layer ◽  
Cropping System ◽  
Amaranthus Retroflexus ◽  
Stellaria Media ◽  
Galium Aparine ◽  
Weed Seeds ◽  
Spring Cereals ◽  
Weed Infestation

This paper presents the results of investigations on the weed infestation and vertical distribution of weed seed bank in rendzina under spring cereals cultivation in crop rotations and monoculture. Used herbicides (MCPA and <i>fenoxaprop-P-etylu</i>) decreased the number of weeds and species composition in comparison with harrowing. In the soil layer of 0-25 cm used in the monoculture there was found about 22,9% weed seeds more than in crop rotation. In the canopy of spring cereals the following weeds dominated: in crop rotation - <i>Chenopodium album, Echinochloa crus-galli and Veronica persica; and in monoculture - Stellaria media, Galium aparine</i> and <i>Chenopodium album</i>. In the soil layer of 0-25 cm used in crop rotation and monoculture the following weed seeds dominated : <i>Amaranthus retroflexus, Chenopodium album</i> and <i>Stellaria media</i>.

scholarly journals Efficacy and selectivity of post-emergent application of flumioxazin and oxyfluorfen in sunflower

2011 ◽  
Vol 57 (No. 11) ◽  
pp. 532-539 ◽  
Author(s):  
M. Jursík ◽  
J. Andr ◽  
J. Holec ◽  
J. Soukup
Keyword(s):  
Chenopodium Album ◽  
Field Trials ◽  
Amaranthus Retroflexus ◽  
Alcohol Ethoxylate ◽  
Thlaspi Arvense ◽  
Full Control ◽  
Application Rates ◽  
Herbicide Treatments ◽  
Small Plot ◽  
Mercurialis Annua

Four efficacy and selectivity small plot field trials were carried out in four sunflower hybrids at two localities in Middle Bohemia during 2008 and 2009 with herbicides containing the active ingredients flumioxazin and fluorochloridone. For Chenopodium album, an efficacy of 97% was found after pre-emergent application of fluorochloridone + acetochlor; the efficacy of oxyfluorfen was 88&ndash;95%; the efficacy of flumioxazin was below 50% at both tested application rates (30 and 60 g/ha) and application timings (2 sunflower leaves and 4 to 6 sunflower leaves); efficacy of flumioxazin increased to 67% and 69%, when surfactants were added (isodecyl alcohol ethoxylate and heptamethyltrisiloxan). Full control of Amaranthus retroflexus was found after all pre-emergent and early post-emergent herbicide treatments; efficacy of late post-emergent herbicide treatments was below 93%. Full control of Mercurialis annua was found only after application of oxyfluorfen. Thlaspi arvense was fully controlled by fluorochloridone + acetochlor (pre-emergent) and oxyfluorfen (in both application terms). Selectivity of the four tested sunflower hybrids to fluorochloridone + acetochlor, bifenox and flumioxazin was acceptable (phytotoxicity 6 to 27%). Higher phytotoxicity (23&ndash;45%) was recorded when surfactants were added to flumioxazin. The highest phytotoxicity (68&ndash;81%) was recorded after the application of oxyfluorfen. &nbsp;

scholarly journals Seedling establishment early on an abandoned field

2001 ◽  
Vol 37 (No. 3) ◽  
pp. 121-127
Author(s):  
J. Štolcová
Keyword(s):  
Species Diversity ◽  
Species Composition ◽  
Seedling Establishment ◽  
Dominant Species ◽  
Chenopodium Album ◽  
Amaranthus Retroflexus ◽  
Abandoned Field ◽  
Thlaspi Arvense ◽  
Weed Infestation ◽  
Small Plot

The effect of sporadic cultivation on seedling establishment on a field abandoned for 1–4 years was investigated in small-plot trials at Prague-Ruzyně in the spring periods 1993–1995. Cultivation included autumn ploughing, spring harrowing and rolling on all plots that were subsequently left to spontaneous weed infestation. Some plots were then mowed or shallowly cultivated in mid-June and late July, others were left without treatment. No significant differences in seedling establishment were found between plots with different treatments. The number of species varied between years, but without a trend to species enrichment or impoverishment. In all years most species were annuals, and species composition did not change in the course of the experiment. The dominant species were Amaranthus retroflexus, Lamium amplexicaule, Echinochloa crus-galli, Chenopodium album, Silene noctiflora and Thlaspi arvense. Species diversity during the experimental years increased due to decreasing dominance of A. retroflexus.

Bentazon Tank-Mixtures for Improved Redroot Pigweed (Amaranthus retroflexus) and Common Lambsquarters (Chenopodium album) Control in Navy Bean (Phaseolus vulgaris)

1995 ◽  
Vol 9 (3) ◽  
pp. 610-616 ◽  
Author(s):  
David A. Wall
Keyword(s):  
Phaseolus Vulgaris ◽  
Active Ingredient ◽  
Chenopodium Album ◽  
Field Studies ◽  
Amaranthus Retroflexus ◽  
Severe Injury ◽  
Navy Bean ◽  
Common Lambsquarters ◽  
Redroot Pigweed ◽  
Crop Maturity

Field studies were conducted from 1991 to 1994 to investigate the effectiveness of reduced rates of bentazon in tank-mixtures with imazethapyr, thifensulfuron, or HOE 075032 for improved control of redroot pigweed and common lambsquarters in navy bean. Tank-mixtures of bentazon at 600 g ai/ha plus imazethapyr at 25 g/ha or HOE 075032 at 5 to 15 g/ha controlled both redroot pigweed and common lambsquarters. These rates represent an approximate 45% reduction in total amount of active ingredient needed to control these weeds compared with full label rates. Bentazon tank-mixtures with 2 or 4 g/ha of thifensulfuron controlled these weeds but caused severe injury and delayed crop maturity. In greenhouse studies, the GR25for HOE 075032 in navy bean was > 90 g/ha, while in soybean it was 16 to 24 g/ha.

scholarly journals Irrigation Timing as a Practice of Effective Weed Management in Established Alfalfa (Medicago sativa L.) Crop

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 550
Author(s):  
Panagiotis Kanatas ◽  
Ioannis Gazoulis ◽  
Ilias Travlos
Keyword(s):  
Medicago Sativa ◽  
Weed Management ◽  
Cultural Practices ◽  
Block Design ◽  
Chenopodium Album ◽  
Stand Density ◽  
Climatic Conditions ◽  
Amaranthus Retroflexus ◽  
Forage Yield ◽  
Medicago Sativa L

Irrigation is an agronomic practice of major importance in alfalfa (Medicago sativa L), especially in the semiarid environments of Southern Europe. Field experimentation was conducted in Western Greece (2016–2018) to evaluate the effects of irrigation timing on weed presence, alfalfa yield performance, and forage quality. In a randomized complete block design (four replications), two cultivars (“Ypati 84” and “Hyliki”) were the main plots, while three irrigation timings were the subplots (split-plot). The irrigation timings were IT-1, IT-2, and IT-3, denoting irrigation 1 week before harvest, 1 week after harvest, and 2 weeks after harvest, respectively. IT-1 reduced Solanum nigrum L. density by 54% and 79% as compared to IT-3 and IT-2, respectively. Chenopodium album L. density was the highest under IT-2. IT-3 resulted in 41% lower Amaranthus retroflexus L. density in comparison to IT-2, while the lowest values were observed under IT-1. Stand density and stems·plant−1 varied between years (p ≤ 0.05). Mass·stem−1 and alfalfa forage yield were affected by the irrigation timings (p ≤ 0.001). Total weed density and forage yield were negatively correlated in both the second (R2 = 87.013%) and the fourth (R2 = 82.691%) harvests. IT-1 and IT-3 increased forage yield, leaf per stem ratio, and crude protein as compared to IT-2. Further research is required to utilize the use of cultural practices for weed management in perennial forages under different soil and climatic conditions.

scholarly journals Dynamics of the Degradation of Acetyl-CoA Carboxylase Herbicides in Vegetables

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 405
Author(s):  
Miroslav Jursík ◽  
Kateřina Hamouzová ◽  
Jana Hajšlová
Keyword(s):  
Linear Models ◽  
Growing Season ◽  
Field Trials ◽  
Baby Food ◽  
Vegetable Production ◽  
The Czech Republic ◽  
Herbicide Residues ◽  
Harvest Intervals ◽  
Small Plot

(1) Background: Aryloxyphenoxy-propionates and cyclohexanediones are herbicides most widely used in dicot crops worldwide. The main objective of the study was to determine the dynamics of herbicide residues in carrot, lettuce, cauliflower, and onion in order to suggest a low level of residues in harvested vegetables. (2) Methods: Small plot field trials were carried out in four vegetables in the Czech Republic. The samples of vegetables were collected continuously during the growing season. Multiresidue methods for the determination of herbicide residues by LC-MS/MS were used. Non-linear models of degradation of individual herbicides in vegetables were calculated using the exponential decay formula. Action GAP pre-harvest intervals for the 25% and 50% maximum residue limit (MRL) and 10 µg kg−1 limit (baby food) were established for all tested herbicides. (3) Results: The degradation dynamics of fluazifop in carrot, onion, and cauliflower was significantly slower compared to quizalofop and haloxyfop. The highest amount (2796 µg kg−1) of fluazifop residues was detected in cauliflower 11 days after application. No residue of propaquizafop and cycloxydim was detected in any vegetable samples. (4) Conclusions: Aryloxyphenoxy-propionate herbicide (except propaquizafop) could contaminate vegetables easily, especially vegetables with a short growing season. Vegetables treated with fluazifop are not suitable for baby food. Lettuce and cauliflower treated by quizalofop are not suitable for baby food, but in onion and carrot, quizalofop could be used. Propaquizafop and cycloxydim are prospective herbicides for non-residual (baby food) vegetable production.

Floristic composition and relative abundance of weeds in annual crops of Manitoba

1991 ◽  
Vol 71 (3) ◽  
pp. 831-839 ◽  
Author(s):  
A. G. Thomas
Keyword(s):  
Relative Abundance ◽  
Chenopodium Album ◽  
Floristic Composition ◽  
Sampling Procedure ◽  
Amaranthus Retroflexus ◽  
Wild Buckwheat ◽  
Wild Oats ◽  
Wild Mustard ◽  
Green Foxtail ◽  
Lamb’S Quarters

Annual surveys for weeds of fields seeded to spring wheat, barley, oats, flax, and canola in Manitoba were conducted during 1978, 1979, and 1981. Fields were surveyed during July and early August each year using a stratified random sampling procedure. Data for the crops and years were combined for analysis. The frequency, the area infested, and the density of the infestation were determined for each species. These three measures of the abundance of the weed were combined into a single synthetic value called relative abundance. Nine of the 152 species recorded by the surveyors accounted for 77% of the total relative abundance. Ranked in order by relative abundance, these species were green foxtail (Setaria viridis (L.) Beauv.), wild oats (Avena fatua L.), wild buckwheat (Polygonum convolvulus L.), annual smartweed (Polygonum spp.), Canada thistle (Cirsium arvense (L.) Scop.), lamb's-quarters (Chenopodium album L.), wild mustard (Sinapis arvensis L.), perennial sow-thistle (Sonchus arvensis L.), and redroot pigweed (Amaranthus retroflexus L.). Green foxtail was the predominant weed with an abundance value three times larger than wild oats or wild buckwheat. The pattern of dominance found in Manitoba fields was similar to results from comparable surveys in Saskatchewan and North Dakota. Key words: Relative abundance, weed survey, weed density, green foxtail, wild oats, wild buckwheat

Sign in / Sign up

Export Citation Format

Share Document