Factors Influencing Postemergence Activity of Chloramben in Velvetleaf (Abutilon theophrasti)

Weed Science ◽  
1987 ◽  
Vol 35 (6) ◽  
pp. 853-857 ◽  
Author(s):  
Wendel B. Orr ◽  
Chaudhry A. Ozair ◽  
Loren J. Moshier
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Dry Weight ◽  
Abutilon Theophrasti ◽  
Growth Stages ◽  
Flowering Stage ◽  
Capsule Production ◽  
Second Year ◽  
One Year ◽  
Origin Of Oil

Efficacy of soil and/or foliage applications of the sodium salt of chloramben (3-amino-2,5-dichlorobenzoic acid) was compared, and the influence of growth stage and oil base within adjuvants on chloramben efficacy was evaluated on velvetleaf (Abutilon theophrastiMedic. # ABUTH). In greenhouse experiments, soil applications reduced growth of velvetleaf treated at the six- to seven-leaf stage (15-cm height) more than did foliage applications. Simulated rainfall applied 48 h after chloramben was applied to foliage significantly increased chloramben activity. Chloramben plus an oil concentrate applied at 3.4 kg ae/ha plus 2.3 L/ha reduced fresh and dry weight less as growth stage advanced in both greenhouse and field experiments. Origin of oil present in the oil concentrate did not influence the activity of chloramben plus oil concentrate in either the greenhouse or in the field. Chloramben plus oil concentrate reduced seed capsule (boll) production 70% or more in velvetleaf plants treated at each of three growth stages in one year and reduced capsule production 90, 90, and 28% in plants treated at early vegetative, late vegetative, and flowering stages, respectively, in the second year. Viability of seed was less from plants treated at a vegetative stage compared to the flowering stage.

scholarly journals Biological Control of the Weedy Plant (Rumex crispus) at the Seedling Growth Stage by the Green Dock Beetle (Gastrophysa viridula)

2019 ◽  
Vol 28 (1) ◽  
pp. 21-31
Author(s):  
Khalid S. Alshallash Khalid S. Alshallash
Keyword(s):  
Biological Control ◽  
Seedling Growth ◽  
Growth Stage ◽  
Biological Control Agent ◽  
Dry Weight ◽  
Control Agent ◽  
Growth Stages ◽  
Rumex Crispus ◽  
Shoot Number ◽  
The Impact

In four glasshouse experiments, the effectiveness of the adult green dock beetle Gastrophysa viridula (Coleoptera: Chrysomelidae), at the effective number of applied individuals, for use as a biological control agent of curled dock, Rumex crispus (Polygonaceae) were studied. The feeding of the beetle was investigated at four different numbers of beetle (0, 1, 2, 3) and at four seedling growth stages of the plant, defined by the average of leaf area per plant (1-1.22 , 2-4.45, 3-11.56, and 4-71.52 cm2/plant). Grazing by one, two or three dock beetles did not result in a significant reduction in dock dry weight or shoot numbers at the youngest growth stage. However, both at later seedling growth stages were significantly affected (P ? 0.0001), at any beetles number. The increase of beetle numbers caused nonsignificant increased effect, in some trials, confirming the impact of a single beetle. Three months after beetle grazing, dock seedlings of first, second and third growth stages were not able to regrow, however, some plants at the 4th growth stage, re-emerged. This suggested that the highest effect of beetle's feeding occurs on the early seedling stages. Statistical analysis showed a positive correlation (0.77) between dry weight and shoot number at all the four seedling growth stages, thus confirming the impact of the beetle on both the dry weight and shoot numbers. Combining beetle grazing with other control methods at older dock seedling stages could, therefore, provide better suppression

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.

The effect of cotton growth stage on response to a sublethal concentration of 2,4-D

2019 ◽  
Vol 33 (2) ◽  
pp. 321-328 ◽  
Author(s):  
John T. Buol ◽  
Daniel B. Reynolds ◽  
Darrin M. Dodds ◽  
J. Anthony Mills ◽  
Robert L. Nichols ◽  
...  
Keyword(s):  
Fiber Length ◽  
Growth Stage ◽  
Field Experiments ◽  
Fruit Set ◽  
Sublethal Concentration ◽  
Growth Stages ◽  
Visible Injury ◽  
Fiber Properties ◽  
Low Concentrations ◽  
Auxin Herbicides

AbstractRecent commercialization of auxin herbicide–based weed control systems has led to increased off-target exposure of susceptible cotton cultivars to auxin herbicides. Off-target deposition of dilute concentrations of auxin herbicides can occur on cotton at any stage of growth. Field experiments were conducted at two locations in Mississippi from 2014 to 2016 to assess the response of cotton at various growth stages after exposure to a sublethal 2,4-D concentration of 8.3 g ae ha−1. Herbicide applications occurred weekly from 0 to 14 weeks after emergence (WAE). Cotton exposure to 2,4-D at 2 to 9 WAE resulted in up to 64% visible injury, whereas 2,4-D exposure 5 to 6 WAE resulted in machine-harvested yield reductions of 18% to 21%. Cotton maturity was delayed after exposure 2 to 10 WAE, and height was increased from exposure 6 to 9 WAE due to decreased fruit set after exposure. Total hand-harvested yield was reduced from 2,4-D exposure 3, 5 to 8, and 13 WAE. Growth stage at time of exposure influenced the distribution of yield by node and position. Yield on lower and inner fruiting sites generally decreased from exposure, and yield partitioned to vegetative or aborted positions and upper fruiting sites increased. Reductions in gin turnout, micronaire, fiber length, fiber-length uniformity, and fiber elongation were observed after exposure at certain growth stages, but the overall effects on fiber properties were small. These results indicate that cotton is most sensitive to low concentrations of 2,4-D during late vegetative and squaring growth stages.

scholarly journals Response and Modeling of Hybrid Maize Seed Vigor to Water Deficit at Different Growth Stages

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3289
Author(s):  
Rongchao Shi ◽  
Ling Tong ◽  
Taisheng Du ◽  
Manoj K. Shukla
Keyword(s):  
Water Deficit ◽  
Drip Irrigation ◽  
Field Experiments ◽  
Seed Vigor ◽  
Growth Stages ◽  
Arid Areas ◽  
Flowering Stage ◽  
Maize Production ◽  
Film Mulching ◽  
Hybrid Maize

Research is imperative to predict seed vigor of hybrid maize production under water deficit in arid areas. Field experiments were conducted in 2018 and 2019 in arid areas of northwestern China to investigate the effects of different irrigation strategies at various growth stages with drip irrigation under film mulching on grain yield, kernel weight, seed protein content, and seed vigor of hybrid maize (Zea mays L.). Water deficit at vegetative, flowering, and grain-filling stages was considered and a total of 16 irrigation treatments was applied. A total of 12 indices of germination percentage, germination index (GI), shoot length (SL), and root length (RL) under different germination conditions (standard germination and accelerated aging); electrical conductivity (EC) of the leachate; and activities of peroxidase, catalase, and superoxide dismutase in seeds were measured and analyzed using the combinational evaluation method (CEM). Furthermore, five water production functions (Blank, Stewart, Rao, Jensen, and Minhas) were used to predict seed vigor evaluated by CEM under water deficit. The results showed that leachate EC was higher under water deficit than that under sufficient irrigation. The SL, RL, and GI of different germination conditions increased under water deficit at the flowering stage. The Rao model was considered the best fitted model to predict the vigor of hybrid maize seeds under water deficit, and an appropriate water deficit at the flowering stage is recommended to ensure high seed vigor of hybrid maize production with drip irrigation under film mulching. Our findings would be useful for reducing crop water use while ensuring seed vigor for hybrid maize production in arid areas.

scholarly journals Rhizopus Head Rot of Confectionery Sunflower: Effects on Yield Quantity and Quality and Implications for Disease Management

1997 ◽  
Vol 87 (12) ◽  
pp. 1226-1232 ◽  
Author(s):  
D. Shtienberg
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Rhizopus Oryzae ◽  
Development Stage ◽  
Crop Growth ◽  
Growth Stages ◽  
Yield Quality ◽  
Crop Growth Stage ◽  
Head Rot ◽  
The Individual

The effects of Rhizopus head rot, caused by Rhizopus oryzae, on the yield of confectionery sunflower and its quality were studied in field experiments conducted from 1994 to 1996. The extent of yield loss was related to the crop growth stage at inoculation. When heads were inoculated at the budding stage, loss was not apparent, because inoculated heads were not infected. When inoculated at the anthesis stage, loss was relatively high (42.5 to 99.1%), and both the number of achenes per head and the individual achene weight were reduced. When heads were inoculated at the seed development stage, yield was not reduced significantly (although the entire receptacle was rotted). Effects of Rhizopus head rot on measures of yield quality were examined as well. Inoculation with R. oryzae did not affect the size of the achenes at any crop growth stage. In contrast, the incidence of discolored achenes (an external sign of nutmeats with a bitter off-flavor) was affected by the disease at all crop growth stages. A survey in eight commercial fields from 1992 to 1996 found that, by the end of the season, incidence of disease ranged from 2.3 to 17.4%. However, since disease intensified late, resultant yield losses were minor and did not exceed 3.1%. Loss figures were estimated by means of a model that was developed and validated in the field experiments. The disease did affect the incidence of discolored achenes. Thus, the conclusion drawn is that the effects of Rhizopus head rot in confectionery sunflower on crop yield is of minimal concern, at least when disease intensifies late, as was the case in the studied fields, but management of the disease should be considered in some situations. The objectives would be to prevent a reduction in yield quality, not yield quantity.

Absorption and Translocation of Buthidazole

Weed Science ◽  
1980 ◽  
Vol 28 (3) ◽  
pp. 352-357 ◽  
Author(s):  
Lloyd C. Haderlie
Keyword(s):  
Nutrient Solution ◽  
Growth Stage ◽  
Dry Weight ◽  
Abutilon Theophrasti ◽  
Plant Tissues ◽  
Steady State Condition ◽  
Foliar Absorption ◽  
Rate Of Absorption ◽  
Glycine Max L ◽  
Soybean Leaves

Absorption and translocation of buthidazole [3-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-4-hydroxy-1-methyl-2-imidazolidinone] was determined in several plant tissues. Buthidazole caused slight effects on seed germination. Germination of soybean (Glycine max L.Merr. ‘Williams’) seeds was inhibited up to 15% and velvetleaf (Abutilon theophrastiMedic.) was stimulated up to 13%. Buthidazole was absorbed by germinating soybeans, velvetleaf, and corn (Zea maysL.) with rate of absorption increasing when roots were capable of absorption. Buthidazole concentrations of 0.5 μM or greater inhibited growth of soybean in the early second-trifoliolate growth stage when supplied to the roots in nutrient solution. Within 96 h, 29% of the buthidazole available to soybeans was absorbed from nutrient solution and 89% of that absorbed was found in the shoots. The expanded leaves of soybean accumulated the majority of the radioactivity. Radioactivity in roots of soybean approached a steady state condition within 96 h, whereas14C continued to increase in shoots. Foliar absorption of buthidazole in soybean greatly increased when any one of several surfactants were used. Soybean dry weight reduction nearly doubled by adding surfactants. Over 60% of the14C-buthidazole applied to soybean leaves was absorbed within 1.5 h, and increased to 73% by 96 h when the nonionic surfactant, AL-411-F3[Phytobland Spray Oil (83%) plus ATPLUS 300F (17%)] was used compared to only 7% in 96 h without the surfactant. There was little or no movement of buthidazole from the treated leaves. Translocation was typical of apoplastic movement.

A review of copper fertilizer management for optimum yield and quality of crops in the Canadian Prairie provinces

2006 ◽  
Vol 86 (3) ◽  
pp. 605-619 ◽  
Author(s):  
S. S. Malhi ◽  
R. E. Karamanos
Keyword(s):  
Seed Yield ◽  
Growth Stage ◽  
Field Experiments ◽  
Seed Quality ◽  
Soil Analysis ◽  
Growth Stages ◽  
Canadian Prairie ◽  
Cu Deficiency ◽  
Yield And Quality

Deficiency of copper (Cu) in Canadian prairie soils is not widespread, but whenever it occurs it can cause a drastic reduction in seed yield and quality of most cereals, especially wheat. Field experiments conducted in western Canada indicated that broadcast-incorporation of granular Cu fertilizers prior to seeding at 3-5.6 kg Cu ha-1 was usually sufficient to prevent Cu deficiency in wheat, and improve seed yield and quality. At lower rates (< 2.0 kg Cu ha-1), broadcast-incorporation of granular Cu fertilizers was not effective, while surface spray-broadcast followed by incorporation of liquid Cu fertilizers was much more effective in increasing seed yield of wheat in the first year of application. Surface broadcast without incorporation and seedrow-placed granular Cu fertilizers were much less effective in improving seed yield of wheat than their foliar or soil-incorporated applications. In the growing season, foliar applications of Cu at 0.20 to 0.28 kg Cu ha-1 to wheat at the Feekes 6 (first node of stem visible at base of shoot or stem elongation), Feekes 10 (sheath of last leaf completely grown or flag-leaf) and early boot growth stages were very effective in restoring seed yield, while Cu applications at the Feekes 2 (four-leaf) or Feekes 10.5 (complete heading) growth stage did not have a consistent effect to correct damage caused by Cu deficiency. Some Cu fertilizers (e.g., Cu oxide) were less effective than others in preventing/correcting Cu deficiency. Soil application at relatively high rates produced residual benefits in increasing seed yield for a number of years. The sensitivity of crops to Cu deficiency is usually in the order (wheat, flax, canary seed) > (barley, alfalfa) > (timothy seed, oats, corn) > (peas, clovers) > (canola, rye, forage grasses). Stem melanosis in wheat was associated with deficiency of Cu in soil, and the disease was reduced substantially with Cu application. A high level of available P in soil was observed to induce/increase severity of Cu deficiency in wheat. Soil analysis for diethylene triamine pentacetic acid- (DTPA) extractable Cu in soil can be used as a good diagnostic tool to predict Cu deficiency, but there was a poor relationship between total Cu concentration in shoots and the degree of Cu deficiency in crops. Application of Cu fertilizers to wheat on Cu-deficient soils also generally improved seed quality. Key words: Application time, Cu source, foliar application, granular Cu, growth stage, placement method, rate of Cu, seedrow-placed Cu, soil incorporation, wheat

scholarly journals Modelling Irrigation Water Requirements at Physiological Growth Stages of Okra Life Cycle Using CROPWAT Model for Derived Savannah and Humid Forest Zones of Nigeria

2016 ◽  
Vol 49 (1-4) ◽  
pp. 20-29
Author(s):  
OrevaOghene Aliku ◽  
Suarau Odutola Oshunsanya
Keyword(s):  
Life Cycle ◽  
Irrigation Water ◽  
Field Experiments ◽  
Growth Stages ◽  
Irrigation Water Requirement ◽  
Flowering Stage ◽  
Water Requirements ◽  
Humid Forest ◽  
Weather Parameters ◽  
Accurate Quantification

Abstract Accurate quantification of irrigation water requirement at different physiological growth stages of okra (Abelmoschus esculentus L.) life cycle is important to prevent over or under irrigation. Field experiments were therefore initiated to model okra irrigation water requirements at the four physiological growth stages of okra life cycle using CROPWAT model. Derived savannah 1 (DS1), derived savannah 2 (DS2) and humid forest (HF) occupying 493.36 ha, 69.83 ha and 305.25 ha respectively were used. Some selected soil physical properties coupled with weather parameters were used to develop irrigation water requirements for okra crop. In DS1, the estimated crop co-efficient (Kc) values were 0.30, 0.52, 0.84 and 0.70 for the germination, crop growth, flowering and fruiting stages, respectively. Corresponding Kc values in DS2 were 0.30, 0.54, 0.90 and 0.84 and in the HF were 0.30, 0.56, 0.87 and 0.86 respectively. Daily crop evapo-transpiration values ranged from 1.16 to 3.36, 1.17 to 3.64, and 1.2 to 3.38 mm day-1 for DS1, DS2 and HF respectively with significant (p = 0.05) peak at the flowering stage for the three locations. Sustainable okra cultivation would require maximum daily irrigation water at flowering stage (reproductive phase) to meet the crop physiological needs and evapo-transpiration demand of the atmosphere.

Response of nonglyphosate-resistant cotton to reduced rates of glyphosate

Weed Science ◽  
2004 ◽  
Vol 52 (1) ◽  
pp. 178-182 ◽  
Author(s):  
Donnie K. Miller ◽  
Robert G. Downer ◽  
B. Roger Leonard ◽  
E. Merritt Holman ◽  
Steve T. Kelly
Keyword(s):  
Data Analysis ◽  
Plant Height ◽  
Growth Stage ◽  
Field Research ◽  
Dry Weight ◽  
White Flower ◽  
Growth And Yield ◽  
Growth Stages ◽  
Flower Number ◽  
Height Reduction

Field research was conducted in 1999 and 2000 to determine the effect of reduced glyphosate rates on growth and yield of nonglyphosate-resistant cotton. Rates of 9, 18, 35, 70, 140, and 280 g ha−1, representing 0.008, 0.016, 0.031 0.063, 0.125, and 0.25, respectively, of the maximum use rate per application (1,120 g ha−1), were applied to cotton at the two-, five-, or nine-node growth stage. On the basis of visual injury estimates, cotton was more tolerant to glyphosate at the nine-node than at earlier growth stages. Plant dry weight was reduced with 70 g ha−1of glyphosate or higher, when applied at the two- and five-node growth stages in two of three experiments. Dry weight was not affected by glyphosate at the nine-node stage. Plant height also was unaffected by glyphosate rates below 70 g ha−1, but height reduction was noted for all growth stages by experiment combinations, with the exception of the nine-node application for both experiments in 2000, with herbicide rates of 70 g ha−1or higher. Cotton maturity delay, as noted by an increase in node above white flower number, was observed only at the highest glyphosate rate applied to two- and five-node cotton in one of three experiments. Percent open boll data analysis indicated a decreased opportunity of observing an open boll with increasing glyphosate rate, and this effect was greater at the five-node compared with the two- and nine-node stages in two of three experiments. Seedcotton yield after all glyphosate applications was equivalent to that for the nontreated control.

scholarly journals Distribution of radioactive products of photosynthesis in Scots pine (Pinus sihestris L.) seedlings during the first vegetation season

2015 ◽  
Vol 42 (4) ◽  
pp. 541-553
Author(s):  
Igor Góral
Keyword(s):  
Scots Pine ◽  
Growth Stage ◽  
Growth Stages ◽  
Vegetation Season ◽  
Photosynthetic Products ◽  
One Year ◽  
Different Growth Stages ◽  
Needle Growth

Dynamics of translocation and distribution of radioactive photosynthetic products in one year old pine (<i>P. silvestris</i> L.) seedlings was investigated at different growth stages. It was found that the utilization of photosynthetic products in particular organs depends greatly on the growth stage. Loses of photosynthetic products as a result of respiration were the smallest at the stage of intensive needle growth and the greatest at the stage of approaching dormancy.

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