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Effect of growth stage on the efficacy of postemergence herbicides on four weed species of direct-seeded rice Full text
2012
Chauhan, Bhagirath Singh | Abugho, Seth Bernard
The efficacy of bispyribac-sodium, fenoxaprop + ethoxysulfuron, and penoxsulam + cyhalofop was evaluated against barnyardgrass, Chinese sprangletop, junglerice, and southern crabgrass when applied at four-, six-, and eight-leaf stages. When applied at the four-leaf stage, bispyribac-sodium provided greater than 97% control of barnyardgrass, junglerice, and southern crabgrass; however, it was slightly weak (74% control) on Chinese sprangletop. Irrespective of the weed species, fenoxaprop + ethoxysulfuron provided greater than 97% control when applied at the four-leaf stage. At the same leaf stage, penoxsulam + cyhalofop controlled 89 to 100% barnyardgrass, Chinese sprangletop, and junglerice and only 54% of southern crabgrass. The efficacy of herbicides was reduced when applied at the eight-leaf stage of the weeds; however, at this stage, fenoxaprop + ethoxysulfuron was effective in controlling 99% of Chinese sprangletop. The results demonstrate the importance of early herbicide application in controlling the weeds. The study identified that at the six-leaf stage of the weeds, fenoxaprop + ethoxysulfuron can effectively control Chinese sprangletop and southern crabgrass, penoxsulam + cyhalofop can effectively control Chinese sprangletop, and bispyribac-sodium can effectively control junglerice.
Show more [+] Less [-]Efficacy of oxadiargyl on cotton under Gezira, Sudan
2012
Ibrahim, N.E., Agricultural Research corporation, Gezira Research Station, Wad Medani, (Sudan) | Babujerm A.G.T., Sudan University for Sciesnce and Technology, Khartoum, (Sudan) | Hamada, A.A., Agricultural Research corporation, Gezira Research Station, Wad Medani, (Sudan)
Field and green house experiments were conducted at the Gezira Research Station (GRS) to evaluate herbicidal efficacy of oxadiargyl on cotton and the effects of rain simulation on its toxicity, as compared to some other herbicides commonly used for weed control on cotton. Oxadiargyl at 0.15-0.30 kg a. i./fed, and its tank mixtures with diuron effected good to excellent (78-91%) weed control early in the season. However, late season weed control was moderate to good (57-74%). The standard oxadiazon and diuron tank mix displayed moderate weed control (58 and 59%) throughout the season. Early in the season oxadiargyl, alone, effected excellent control (100%) of the dominant weeds, except Commelina kotschyi and Aristolochia bracteolata. The tank mix of oxadiargyl and diuron adequately controlled C. kotschyi, but not A. bracteolata. Following frequent rains oxadiargyl displayed high toxicity to cotton. The herbicide significantly reduced leaf area index (LAI), crop stand and height. However, recovery occurred late in the season. At harvest all herbicide treatments out yielded the unweeded control, but were out yielded by the hand weeded check. Simulated rain enhanced toxicity of oxadiargyl, oxyfluorfen and oxadiazon. However, toxicity of fluomeuron and metolachlor mix, and pendimethalin was less affected. It was concluded that the influence of simulated rain on selectivity of the herbicides to cotton, was modulated by growth stage, route of entry into the plant and by mode of action. Fluometuron and metalochlor mix and pendimethalin may be used safely for weed control on cotton in both the irrigated and rain fed sectors. Oxadiazon and oxyfluorfen are more suitable on furrow irrigated cotton where rainfall is less frequent. Use of oxadiargyl must be restricted to irrigated areas where rainfall does not coincide with cotton emergence
Show more [+] Less [-]Influence of environmental parameters on efficacy of herbal medicines Full text
2012
Eloff, Jacobus Nicolaas | Netshiluvhi, Thiambi Reuben
Thesis (PhD)--University of Pretoria, 2012. | It is evident that herbal medicines continue to be the mainstay of healthcare systems and source of livelihoods of many local communities in South Africa and other developing countries. As a result, there is an overwhelming dependence on medicinal products harvested from natural populations. This dependence has led to local extinction of some important medicinal plants that include Warburgia salutaris and Cassine transvaalensis in South Africa. Cultivation has great potential to relieve the pressure on natural populations. However, some traditional practitioners and scientists believe that cultivation may weaken medicinal properties and that increased secondary metabolites may form only under stress conditions, respectively. This is certainly true in some cases especially where infections with pathogens, browsing by herbivores or competition takes place in nature. It is however not clear how true this is with environmental stresses. The overall aim of this study was to evaluate to what degree different environmental conditions influenced antimicrobial and antioxidant activities of plants cultivated outside their natural environment. In order to address the aim of the study, exploratory and in-depth studies were undertaken. The exploratory study comprised long-lived Combretum collinum Fresen. (Combretacea), Terminalia sericea Burch. ex DC. (Combretaceae) and Sclerocarya birrea (A. Rich.) Hochst. (Anacardiaceae). Short-lived herbaceous Tulbaghia violacea Harv. (Alliaceae) and Hypoxis hemerocallidea Fish, C.A.Mey,&Avé- Lall, (Hypoxidaceae), were included as part of the exploratory study. The in depth studies were further undertaken, also with short-lived herbaceous Leonotis dysophylla Benth. (Lamiaceae), Bulbine frutescens (L.) Willd. (Asphodelaceae) and T. violacea. Acetone leaf extracts of all plants were studied for antimicrobial activity against bacteria (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis) and fungi (Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus). Extracts were also studied for antioxidant activity against Trolox and L-ascorbic acid standard oxidants using 2,2’-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) and 2,2- diphenyl-2-picryl-hydrazyl (DPPH) free radicals, respectively. The exploratory study tested the effect of different rates of annual rainfall (≥870 mm/year, 651 mm/year and 484 mm/year) on the antibacterial activity of C. collinum, T. sericea and S. birrea growing in nature. The minimum inhibitory concentration (MIC) of acetone extracts of air-dried leaves was determined by using microplate serial dilution technique. Thin layer chromatography (TLC) and bioautography determined chemical constituents and antibacterial activity of extracts, respectively. The majority of extracts had low MIC values, which indicated good antibacterial activity against test bacteria (MIC of 240 μg/ml - 60 μg/ml). Leaf extracts of C. collinum and S. birrea against S. aureus (range of 390 – 100 μg/ml), E. coli (310 -70 μg/ml) and P. aeruginosa (520 - 70 μg/ml) had antibacterial activity increased significantly with low rate of annual rainfall. However, extracts of T. sericea against P. aeruginosa (240 - 100 μg/ml) and E. faecalis (150 - 820 μg/ml) had antibacterial activity significantly increased and decreased, respectively. Extracts of C. collinum and S. birrea against E. faecalis as well as T. sericea against S. aureus and E. coli did not show any clear correlation between activity and different rates of annual rainfall. Inconsistent results suggest that other factors in nature such as genetic variability, age difference, pathogens, herbivores or allelopathy (competition) might have influenced the antibacterial activity of extracts. The results indicate that the antimicrobial activity of plants growing in nature may be highly variable. In order to eliminate possible effect of those factors common in nature, another exploratory study was undertaken using clone T. violacea and H. hemerocallidea of similar age (Chapter 3). Plants were grown under controlled conditions that included irrigation with 1000 ml of distilled water in intervals of 3, 14 and 21 days outside natural environment. Dry mass of all plants was reduced significantly (P≤0.05) with watering interval of 21 days, which indicated the effect of water stress. Air-dried leaves of all plants were finely ground and extracted with acetone. Extracts had good antibacterial activity as attested by low MIC values (< 1 mg/ml) across watering intervals. Differences in the antibacterial activity of the extracts against test bacterial between water treatments were not statistically significant (P≤0.05). Furthermore, there was no clear correlation between the activity of extracts and water treatments in terms of the MIC and total activity values or chemical constituents. The results in general suggest that cultivation under optimal watering intervals may not necessarily weaken the biological activity of extracts. To complement the above findings, in depth studies were also undertaken with clone L. dysophylla, T. violaceae and B. frutescens of similar age growing under controlled conditions outside natural environment. The studies determined the influence of a wide range of water (50 ml – 500 ml) and temperature (15°C and 30°C) treatments on antibacterial, antifungal and antioxidant of extracts. With the exception of a crassulacean acid metabolism (CAM) plant, B. frutescens, transpiration, dry mass and leaf areas of the other two plants were reduced significantly (P 0.05) under high temperature of 30°C and lowest water supply of 50 ml. Acetone leaf extracts had some biological activity. Differences in the majority of antibacterial and antifungal activities of extracts between water and temperature treatments were not statistically significant. With the exception of the influence of temperature, the majority of the antioxidant activity of extracts was almost similar between water treatments. However, the significant reduction of the antioxidant activity of all extracts under high temperature of 30°C was indicative of great sensitivity to high temperatures. The overall findings suggest that the biological activity of plants is more likely to vary widely in nature than under controlled conditions outside the natural environment. This is an indication that natural environment cannot always guarantee high and stable biological activity. As a result, beliefs by some traditional practitioners and scientists that cultivation weakens medicinal properties and good secondary metabolites form only under stress, respectively, cannot be widely substantiated. Therefore, the study encourages cultivation of medicinal plants. It has potential to optimise yield of biomass production, and ensure uniform and quality biological activity as well as reduce misidentification. | Paraclinical Sciences | unrestricted
Show more [+] Less [-]Efficacy of diffusion barriers on shelf-life of peas
2012
Gupta, Silvy | Alam, Shafiq
A study was conducted to assess the effect of storage parameters i.e. pectin coating concentrations and packaging materials on shelf life and quality of peapods stored under ambient conditions (17–22°C and 75–85%). Pectin coating of various concentrations (0.5%, 1.0%, 1.5% and 2.0%) were tried on fresh peapods in order to extend the marketing period. Coating was applied by immersion method. Coated and uncoated peapods were stored in open crates, LDPE, HDPE (100 gauge) under ambient conditions. The quality of stored peapods was evaluated on the basis of physiological loss in weight, colour, texture, decay %, chlorophyll content and organoleptic attributes at regular intervals. It was observed that 1.0% pectin coated peas packed in LDPE packages recorded minimum changes in the quality parameters as compared to 0.5, 1.5 & 2.0% pectin coated and uncoated peas, it was possible to extend the shelf life of peas upto 6 days with acceptable quality attributes.
Show more [+] Less [-]The efficacy of bitter blockers on health-relevant bitterants Full text
2012
Nicole J. Gaudette | Gary J. Pickering
Current strategies for decreasing the bitterness of conventional foods often involve the addition of sucrose and sodium chloride. However this has limited application with functional foods, as they are health promoting, and other approaches are required. This study assesses the efficacy of high and low concentrations of five bitter inhibiting compounds [β-cyclodextrin (β-CYCLO), homoeriodictyol sodium salt (HED), zinc sulphate monohydrate (ZnSO4), magnesium sulphate (MgSO4), carboxymethylcellulose sodium salt (CMC)] on the perceived bitterness of high and low concentrations of (+)-catechin and caffeine – two ingredients used in functional food formulations. Intensity ratings (bitterness, sourness, saltiness, sweetness, savoriness, astringency, ‘other’) of bitterant-bitter blocker binary solutions were collected from a panel of twelve, in duplicate, using a 15 cm line scale. Overall, β-CYCLO and HED were the most effective blockers at decreasing the bitterness of (+)-catechin, while the bitterness of caffeine was reduced most effectively by HED. Results also demonstrate that the bitter reducing capacity of these blockers is bitterant dependent. In general, these bitter blockers elicit minimum side tastes and sensations, although astringency and viscosity intensities are increased under some conditions. We conclude that some bitter blockers show considerable potential for decreasing the bitterness of phenols and caffeine in functional food formulations.
Show more [+] Less [-]The efficacy of bitter blockers on health-relevant bitterants Full text
2012
Gaudette, Nicole J. | Pickering, Gary J.
Current strategies for decreasing the bitterness of conventional foods often involve the addition of sucrose and sodium chloride. However this has limited application with functional foods, as they are health promoting, and other approaches are required. This study assesses the efficacy of high and low concentrations of five bitter inhibiting compounds [β-cyclodextrin (β-CYCLO), homoeriodictyol sodium salt (HED), zinc sulphate monohydrate (ZnSO₄), magnesium sulphate (MgSO₄), carboxymethylcellulose sodium salt (CMC)] on the perceived bitterness of high and low concentrations of (+)-catechin and caffeine – two ingredients used in functional food formulations. Intensity ratings (bitterness, sourness, saltiness, sweetness, savoriness, astringency, ‘other’) of bitterant-bitter blocker binary solutions were collected from a panel of twelve, in duplicate, using a 15cm line scale. Overall, β-CYCLO and HED were the most effective blockers at decreasing the bitterness of (+)-catechin, while the bitterness of caffeine was reduced most effectively by HED. Results also demonstrate that the bitter reducing capacity of these blockers is bitterant dependent. In general, these bitter blockers elicit minimum side tastes and sensations, although astringency and viscosity intensities are increased under some conditions. We conclude that some bitter blockers show considerable potential for decreasing the bitterness of phenols and caffeine in functional food formulations.
Show more [+] Less [-]A Study on Efficacy of Employee Training: Review of Literature Full text
2012
Chidambaram,Vijayabanu | Ramachandran,Amudha
The success of any organization depends on appropriate use of human assets available in the organization. All other assets could only be supplementary to human assets. Towards augmenting the human resources and to cope with changes – both internal and external, the organization has to concentrate necessarily on developing the ability, wisdom and skills of its workforce. For the development of human asset, ‘training’ becomes the base. Training is a tool to attain individual, organizational needs related to the jobs undertaken and is also intended to improve the work culture of the group involved in a group task. An ideal training programme can be expected to change the attitude, skills and develop forward vision of the participants towards the task. This paper summarizes the results of the literature review on the effectiveness of training programmes of employees from diverse perspective.
Show more [+] Less [-]Design considerations on the proof of efficacy of functional foods Full text
2012
Baldi, Ileana | Gregori, Dario
Functional food research encompasses several types of study designs, including observational studies and randomized clinical trials (RCTs). Markers that can predict potential benefits or risks relating to certain health conditions are often the primary endpoints of such studies since a direct measurement of the effect of food on health and well-being and/or reduction of disease risk is often not possible. Whether RCT should be at the top of the pyramid also in nutritional research remains a controversial issue. Undoubtedly, further research is needed to redesign RCT methodology that would adequately serve the need to demonstrate the health effects of foods. We address this functional food research question by assuming that there is a known relationship between the surrogate and the true endpoint explored during the surrogacy assessment. Statistical inference on the true (unobserved) endpoint is derived on the basis of its predicted values. We illustrate this approach through a motivating example from the literature on coronary heart disease, integrated with simulated scenarios.
Show more [+] Less [-]Efficacy of extracts of immature mango on ovine gastrointestinal nematodes Full text
2012
Nery, Patrícia S. | Nogueira, Flávia A. | Oliveira, Neide J. F. | Martins, Ernane R. | Duarte, Eduardo R.
The principal health problem in small ruminants is helminthiasis and the rapid development of nematode resistance to anthelminthics has limited the success of control in several countries, stimulating the search for alternatives. In this study, extracts of immature fruits of the mango Mangifera indica L. var Ubá were evaluated for inhibition of larval development and fecal egg count reduction in sheep naturally infected with gastrointestinal nematodes. In the phytochemical analyses, tannins and flavonoids were the metabolites identified. Aqueous extracts of immature fruits at 100 mg ml⁻¹ showed 100 % inhibition of larval development. The LC₉₀ of the extract was 35.9 mg ml⁻¹ and the in vivo anthelminthic efficacy at 0.740 g kg⁻¹ (BW, orally) was 53 %. The identification of larvae showed that 99.8 % were Haemonchus spp. In vitro and in vivo results indicate that this fruit could assist ovine nematode control.
Show more [+] Less [-]Efficacy of commercial herbal pesticides on sucking pests of pomegranate.
2012
Jafari nodoushan, Ali | Shamszadeh, Mehdi
Pomegranate aphid and mite is one of important pests of pomegranate trees in Iran and main damage of aphid and mite is caused in spring and summer, respectively. These pests feed on the sap of the leaves and fruit skin and cause weakness and loss of trees product. In the present study, in 2010 year, the effect of different concentrations (2000 & 2500 ppm) of palizin® and tondexir® were tested with four replications, in Tehran, Khorasan- Razavi, Yazd, Lorestan and Markazi regions. The treatments were compared considering aphids and mites population before and after treatment. Based on result, application of palizin® (insecticidal and acaricidal soap) and tondexir® (Hot pepper extract insecticide emulsifiable concentrate) with 2000 ppm concentration, were effective in decreasing pomegranate aphids damage, respectively. Key Words: Pomegranate, pomegranate aphid, pomegranate mite, control, herbal pesticides
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