Showing papers on "Azadirachta published in 1994"
TL;DR: A 1% neem oil-kerosene mixture may provide economical personal protection from mosquito bites and reduced biting of human volunteers and catches of mosquitoes resting on walls in the rooms.
Abstract: The repellent action of neem oil (extracted from the seeds of Azadirachta indica A. Juss) was evaluated on mosquitoes at two villages near Delhi, India. Kerosene lamps containing neem oil were burned in the living rooms, and mosquitoes resting walls or attracted to human bait were collected inside rooms from 1800 to 0600 h. Neem oil (0.01-1%) mixed in kerosene reduced biting of human volunteers and catches of mosquitoes resting on walls in the rooms. Protection was more pronounced against Anopheles than against Culex. A 1% neem oil-kerosene mixture may provide economical personal protection from mosquito bites.
125 citations
TL;DR: It is shown that azadirachtin, a compound from the neem tree, Azadirachta indica, and selected semi-synthetic derivatives, block the development of the motile male malarial gamete in vitro.
Abstract: We have shown that azadirachtin, a compound from the neem tree, Azadirachta indica, and selected semi-synthetic derivatives, block the development of the motile male malarial gamete in vitro. Changes in the hemiacetal group at position C11 in the molecule result in a loss of activity in this assay. The motility of fully formed male gametes, and other selected flagellated cells, is unaffected by azadirachtin in vitro. These findings raise the possibility of developing azadirachtin-based compounds as antimalarials with transmission-blocking potential, as well as permitting the further study of structure-activity relationships in these compounds.
95 citations
TL;DR: It is demonstrated that in principle, populations of S. lineatus can be manipulated with semiochemicals when these arc deployed in a ‘push-pull’ or ‘stimulo-deterrent diversionary’ strategy.
67 citations
Journal Article•
TL;DR: Five species of Philippine plants, reported in the literature to have insecticidal properties, were selected for investigation and Lansones and atis were the most effective against larvae of Ae.
Abstract: Five species of Philippine plants, reported in the literature to have insecticidal properties, were selected for investigation, namely: Anona squamosa ("atis" or sugar apple), Eucalyptus globulus ("bagras" or olive gum eucalyptus), Lansium domesticum ("lansones"), Azadirachta indica ("neem") and Codiaeum variegatum ("San Francisco" or croton). These were screened and assayed for their larvicidal potential against Aedes aedes aegypti (Linnaeus) and Culex quinquefasciatus (Say) by exposing 3rd-4th instar larvae to seven different concentrations (two-fold dilutions starting from 100 g% up to 1.5625 g%) of the crude aqueous extract derived from fresh leaves. Three trials were performed for each species of mosquito and for each of the five plants to determine the average mortality rate at various concentrations after 24 and 48 hours exposure. Probit analysis using the NCSS program was employed to determine the LD50 and LD90 values in order to compare the larvicidal potency of the five plants and to compare the susceptibility of Ae. aegypti and Cx. quinquefasciatus. The extracts exerted maximum insecticidal activity after 48 hours exposure. Lansones and atis were the most effective against larvae of Ae. aegypti and Cx. quinquefasciatus, respectively. Ae. aegypti was more susceptible than Cx. quinquefasciatus with respect to lansones and neem but Cx. quinquefasciatus was more susceptible than Ae. aegyti with respect to eucalyptus, San Francisco and atis. These varying results are probably due to differences in levels of toxicity among the active insecticidal ingredients of each plant and in the physiological characteristics of the two mosquito species.
62 citations
TL;DR: Callus produced from leaves of a Ghanaian strain of the neem tree, Azadirachta indica A. Juss has been shown to produce the natural insecticide azadirachtin when grown in a defined medium and has 100% antifeedant activity.
Abstract: Callus produced from leaves of a Ghanaian strain of the neem tree, Azadirachta indica A. Juss has been shown to produce the natural insecticide azadirachtin when grown in a defined medium. The azadirachtin was isolated by standard procedures of solvent partition and column chromatography monitored by supercritical fluid chromatography. Biological activity was monitored with antifeedant tests using the desert locust (Schistocerca gregaria Forsk.). The azadirachtin was identified by chromatography on three independent chromatographic systems (SFC, HPLC & TLC) and two thin-layer colour tests. It has 100% antifeedant activity at < 0.04mg litre−1. The yield of azadirachtin was 0.0007% based on dry weight of callus.
47 citations
TL;DR: Neem, Azadirachta indica (A. Juss.), seed oil (NSO) applied to leaf discs at a concentration of 1.0% resulted in 94% to 100% mortality of second instar nymphs of currant‐lettuce aphid, Nasonovia ribis‐nigri (Mosley), and green peach aphids, Myzus persicae (Sulzer), after nine days.
Abstract: Neem, Azadirachta indica (A. Juss.), seed oil (NSO) applied to leaf discs at a concentration of 1.0% resulted in 94% to 100% mortality of second instar nymphs of currant-lettuce aphid, Nasonovia ribis-nigri (Mosley), and green peach aphid, Myzus persicae (Sulzer), after nine days. The equivalent amount of pure azadirachtin (AZA) (a40 ppm), the principle active ingredient of neem, was as effective as NSO. The survival of adult aphids was unaffected by NSO or AZA, but the survival of offspring from treated adult M. persicae and N. ribis-nigri was reduced significantly. The lethal concentration of AZA resulting in 50% mortality of second instar nymphs of nine species of aphids ranged from 2.4 ppm for M. persicae on pepper to 635.0 ppm for the strawberry aphid, Chaetosiphon fragaefolii (Cockerell), on strawberry. For M. persicae, the growth regulating effect of AZA was influenced by the host plant and the nymphal instar treated.
47 citations
Journal Article•
TL;DR: The ethanolic extract was found to be more active inhibiting 90% of the isolates at a concentration of 100 ug/ml while the MIC 50s and MIC 90s of the aqueous extract were 500 and > 500 uG/ml whereas the values for ketoconazole were 1 and 2.5 ug /ml respectively.
Abstract: The antidermatophytic activity of the aqueous and ethanolic extracts of Neem (Azadirachta indica) leaves was investigated against 88 clinical isolates of dermatophytes by agar dilution. The isolates included Microsporum canis (50), M.audouinii (5), Trichophyton rubrum (6), Tmentagrophytes (5), T.violaceum (12), T.simii (5) T.verrucosum (1) T.soudanense (l), T.erinacei(1) and Epidermophyton floccosum (2). The results were compared with the minimal inhibitory concentrations of ketoconazole. The ethanolic extract was found to be more active inhibiting 90% (MIC 90) of the isolates at a concentration of 100 ug/ml. The MIC 50s and MIC 90s of the aqueous extract were 500 and > 500 ug/ml whereas the values for ketoconazole were 1 and 2.5 ug/ml respectively.
47 citations
TL;DR: The results suggest that honey bees may be successfully utilized in blooming crops that have been treated with doses of NSE sufficient to control phytophagous insect pests.
Abstract: A standardized, oil-free neem (Azadirachta indica A. Juss) seed extract (NSE) was tested for repellency to honey bees using a feeding-dish choice bioassay, and to honey bees and other pollinators in field applications on blooming canola. Foraging honey bee workers were able to discriminate between untainted sugar syrup and syrup containing formulated NSE at concentrations as low as 0.1 ppm azadirachtin, the principal active ingredient of NSE. However there were no significant differences in the numbers of foraging bees collected in neem-treated, solvent-treated, or untreated canola plots. Other pollinator. species present were similarly unaffected. Our results suggest that honey bees may be successfully utilized in blooming crops that have been treated with doses of NSE sufficient to control phytophagous insect pests. The results of this study also suggest that using feeding-dish bioassays to screen potential repellent compounds, although demonstrating the ability of honey bees to detect compounds, may not yield similar results in the field.
43 citations
TL;DR: Callus and micropropagated shoots were initiated from leaf explants of the neem tree and results indicated that antifeedants were still being formed and that levels increased after maximum biomass was attained.
Abstract: Callus and micropropagated shoots were initiated from leaf explants of the neem tree, Azadirachta indica A. Juss. A variety of whole plant and in vitro cell cultures from neem seedlings of Ghanian origin were tested for insect antifeedant compounds using the desert locust (Schistocerca gregaria (Forskal)). Feeding suppression occurred when whole extracts of seed, leaf, callus, suspension and shoot cultures were tested in no-choice feeding bioassays. Controls of sucrose, carrot callus and the plant growth medium showed no feeding deterrence. Azadirachtin, the main known antifeedant in neem seed kernels, was quantified from a seed extract by HPLC but was not detected in any of the other extracts. Antifeedancy was determined during batch growth of a suspension culture which had been in culture for 5 months; results indicated that antifeedants were still being formed and that levels increased after maximum biomass was attained.
40 citations
TL;DR: Methanol extracts of a number of tropical and subtropical plants, such as Ailanthus altissima, Acanthospennum hispidum, Hentiera littoralis, and seed cake of Azadirachta indica ("neem cake"), have been tested for antifeedant, insecticidal, insect growth regulating (IGR), nematicidal, bactericidal, and fungicidal activity.
Abstract: Methanol extracts of a number of tropical and subtropical plants, such as Ailanthus altissima, Acanthospennum hispidum, Hentiera littoralis, and seed cake of Azadirachta indica ("neem cake"), have been tested for antifeedant, insecticidal, insect growth regulating (IGR), nematicidal, bactericidal, and fungicidal activity. Antifeedant activities towards Epilachna vanvestis were observed with the Ailan- thus, Acanthospennum, Hentiera, and neem cake extracts, resp., IGR activities were found in addition with Ailanthus and neem cake extracts. Bactericidal and fungicidal effects were observed with extracts from A. hispidum. We report on isolation, structure, and biological activity of some of the active principles.
37 citations
TL;DR: A botanical insecticide derived from seeds of the neem tree, Azadirachta Indica A. Juss, was tested for the “bait and kill” strategy for control of outbreaks of the mountain pine beetle.
Abstract: A botanical insecticide derived from seeds of the neem tree, Azadirachta Indica A. Juss, was tested for the “bait and kill” strategy for control of outbreaks of the mountain pine beetle, Dendroctonus ponderosae Hopkins. Application of neem into frills at the base of beetle-attacked lodgepole pine, Pinus contorta Douglas var. latifolia Engelmann, trees reduced numbers of mountain pine beetle larvae per unit area of bark, decreased densities of larvae per unit length of adult gallery, and increased larval mortality when applied at doses > 0.25 g (AI) (azadirachtin) per tree. Suggestions for improving the efficacy of neem treatments are discussed.
Journal Article•
TL;DR: Effect of oral administration of crude aqueous neem extract on serum testosterone and other blood constituents was studied in the male Wistar rats for 10 weeks and showed significant decreases in total testosterone, total bilirubin and K+ in serum.
Abstract: Effect of oral administration of crude aqueous neem extract on serum testosterone and other blood constituents was studied in the male Wistar rats for 10 weeks. The neem treatment resulted in significant decreases (p < 0.01) in total testosterone, total bilirubin and K+ in serum. There were also increases (p < 0.05) in packed cell volume, mean corpuscular haemoglobin concentration, red blood cell, white blood cell and lymphocyte counts without showing any cytotoxic effects in the body.
TL;DR: In this article, a field experiment was conducted to investigate the influence of various rain water harvesting and conservation techniques on soil moisture storage, growth and biomass production of Azadirachta indica (neem) in the Indian desert.
TL;DR: It is the conclusion that for subsequent fractionation to reach the last active fraction, the hexane extract is the most useful starting material.
15 Dec 1994
TL;DR: Results indicated that neem extracts are very useful far carrying biocontrol agent to the root rhizosphere of egg plant (Solanum melongena) planted in pots and that the neem cake extracts support the growth of P. lilacinus.
Abstract: An experiment was conducted to convey the spores of Paecilomyces lilacinus to the soil by mixing the spores of this bio-control agent in neem cake (Azadirachta indica) extracts (5 and 10%). The results of the experiments indicated that neem extracts are very useful far carrying biocontrol agent to the root rhizosphere of egg plant (Solanum melongena) planted in pots. This method of application of spores facilitates rational integration of biocontrol agent and botanical leading to the exploitation of beneficial effects of both components in the management of Meloidogyne incognita. Addition of neem cake extracts (5 and 10%) mixed with spores of P. lilacinus to the soil was effective in the management of M. incognita on egg plant. Results also indicated that the neem cake extracts (5 and 10%) support the growth of P. lilacinus.
Journal Article•
TL;DR: Neem leaf alcoholic extract was investigated for its effects on the ECG and blood pressure of rat and pre-treatment with either atropine or mepyramine failed to prevent the hypotensive effect of NLE.
Abstract: Neem leaf alcoholic extract (NLE) was investigated for its effects on the ECG and blood pressure of rat. Intravenous administration of NLE (100, 300 and 1000 mg/kg) resulted in initial bradycardia followed by cardiac arrhythmia in rats. NLE produced a significant and dose-related fall in blood pressure which was immediate, sharp and persistent. Pre-treatment with either atropine or mepyramine failed to prevent the hypotensive effect of NLE.
TL;DR: Findings suggests that early exposures to precursors of N-nitroso compounds via medicinal plants might contribute to total risk posed by environmental carcinogens in Nigeria.
Journal Article•
01 Dec 1994
TL;DR: Bare-root treatment of chilli seedlings with extracts of decomposed and undecomposed oil-cakes and leaves of neem and castor provided protection against root-knot disease caused by Meloidogyne incognita.
Abstract: Bare-root treatment of chilli (Capsicum annuum) seedlings with extracts of decomposed and undecomposed oil-cakes and leaves of neem (Azadirachta indica) and castor (Ricinus communis) provided protection against root-knot disease caused by Meloidogyne incognita. A curative effect was also noted when roots of pre-infected seedlings were given a similar treatment. Suppression of root-knot development was greater in pre-infected (therapeutic use) seedlings than in those inoculated after dir treatment (prophylactic use). Extracts of decomposed materials were more effective than those of undecomposed ones. Moreover, oilcakes and neem were more effective than leaves and castor.
TL;DR: Dinitrophenylamino, dansyl, and biotin groups have been covalently attached to several azadirachtin derivatives via a linker group to give fluorescent or immunogenic compounds that generally retain the biological properties of azadIRachtin.
TL;DR: A simple method for the extraction and purification of small alpha-peptides from the young leaves of Azadirachta indica was developed using a Dowex-50 column, which would act as a cost-effective alternative for the isolation of alpha- peptides having less than six amino acids.
TL;DR: A new meliacin, 11α-hydroxy-12norazadirachtin has been isolated from the seeds of Azadirachta indica Structure has been assigned based on spectral data and comparison with its 11β-epimer as discussed by the authors.
Abstract: A new meliacin, 11α-hydroxy-12-norazadirachtin has been isolated from the seeds of Azadirachta indica Structure has been assigned based on spectral data and comparison with its 11-β-epimer
Dissertation•
01 Jan 1994
TL;DR: The results indicate that neem has potential for operational use in conifer greenhouses and seed orchards and that NSE-5 significantly reduced aphid numbers on trees that initially had high populations.
Abstract: An extract from seeds of the neem tree, Azadirachta indica (Juss.), enriched with azadirachtin, a proprietary product (NSE-5), was evaluated in three experiments (Exp.) for control of the green spruce aphid, Elatobiurn abietinum (Walker), on potted spruce trees in a greenhouse. The extract in Exp. 1 and 2 was first applied on 15 February 1993 when green spruce aphid populations were initially low; aphid populations were observed weekly for 15 weeks thereafter. In Exp. 1, foliar applications to the run-off point of 150 ppm azadirachtin applied three times (biweekly) held populations below 5.3 aphids per 6 cm twig samples; populations on trees treated at 75 ppm, or with the control (emulsifier) treatment only, reached 32.2 and 26.9 aphids per sample, respectively. When five applications were made weekly in Exp. 2, suppression to below 14 aphids per sample was achieved with both 150 and 75 ppm treatments, while populations on control trees peaked at 36.8 aphids per sample. NSE-5 at 150 ppm in Exp. 3 significantly reduced aphid numbers on trees that initially had high populations. The results indicate that neem has potential for operational use in conifer greenhouses and seed orchards. Dedicated to the memory of my sister, Ellen Margaret Partridge.
TL;DR: In this paper, fresh undried winter leaves of Azadirachta indica were fed with [2-14C, 4R-3H1] MVA.
Abstract: Fresh undried winter leaves of Azadirachta indica were fed with [2-14C, 4R-3H1] MVA. Atomic and isotopic ratios in nimocinol & nimocinolide, thus isolated showed the loss of one 14C from the side chain and four tritium atoms - one from side chain and three from apotetracyclic triterpene skeleton. The biosynthetic pathway thus established suggested the involvement of euphol (Δ8,9 compound) which is isomerised to butyrospermol (Δ7,8 compound) followed by an apo-rearrangement during which one methyl migrates from C-14 to C-8 and double bond from C-7 to C-14.
Journal Article•
TL;DR: The optimum conditions to establish in-vitro plantlets of Neem from cultures of embryos is described and embryos of the size range of 3 mm-5 mm were ready for transplantation within 45 days of their rescue.
Abstract: The optimum conditions to establish in-vitro plantlets of Neem ( Azadirachta indica ) from cultures of embryos is described. Embryos were cultured after careful dissection from fruits collected 30 days after pollination. Several combinations of culture media were tried and the optimum conditions for germination was in the presence of high sucrose (12%) with 0.01 mg/1 NAA and 0.1 mg/1 BAP. Embryos of the size range of 3 mm-5 mm were ready for transplantation within 45 days of their rescue.
Journal Article•
TL;DR: Rooting trial were conducted terminal and sub-terminal leafy softwood binodal segments made from actively growing branches of neem, finding that the segments rooted easily even without auxin treatment and their rooting response improved on their treatment with potassium permanganate and ascorbic acid.
Abstract: Rooting trial were conducted terminal and sub-terminal leafy softwood binodal segments made from actively growing branches of neem. The terminal segments rooted easily even without auxin treatment. The segments taken from the sub-terminal greenwood zone were only moderately easy to root but their rooting response improved on their treatment with potassium permanganate and ascorbic acid. Relevance of the findings for the mass clonal multiplication of neem has been discussed.
15 Jun 1994
TL;DR: Treatment of the soil with the oil seed cakes and pesticides considerably decreased the population of root knot nematode in Davana.
Abstract: Greenhouse studies were carried out to determine the comparative performance of oil-seed cakes of neem (Azadirachta indica Juss.), mahua (Madhuca indica Gmel.), castor (Ricinus communis L.) and the pesticides aldicarb, carbofuran and bavistin against the root knot nematode, Meloidogyne incognita infecting davana (Artemisia pallens). Neem oil seed cakes performed best and significantly increased the growth/yield of the crop, followed by aldicarb, castor cake, carbofuran, bavistin and mahua cake. Treatment of the soil with the oil seed cakes and pesticides considerably decreased the population of root knot nematode in Davana. Mahua cake and bavistin gave poor results.