Showing papers on "Azadirachta published in 1998"

Ovicidal Activity of Neem Products (Azadirachtin) Against Culex Tarsalis and Culex Quinquefasciatus (Diptera: Culicidae)

Abstract: Bioactive compounds contained in the seed kernel and other parts of the neem tree (Azadirachta indica A. Juss) have been found to show insecticidal activities and other effects in many species of insects. These activities include antifeedancy, growth regulation, fecundity suppression, male sterility, oviposition repellency, changes in biological fitness such as loss of flying ability, immunodepression, enzyme inhibition, splitting of biological rhythms, and so forth. We investigated the ovicidal effects of various formulations of azadrirachtin (AZ) against the mosquitoes Culex tarsalis Coquillett and Culex quinquefasciatus Say. The formulations tested were wettable powder Azad WP10, emulsifiable concentrate Azad EC4.5, and technically pure AZ. The ovicidal activity of the test neem products was influenced by concentration of AZ, age of the egg rafts, and age of the neem preparations. Other factors such as formulation and mosquito species were also involved in the degree of ovicidal activity. When the egg rafts were deposited directly in fresh neem suspension and left there for 4 h before transfer to untreated water, 1 ppm of AZ produced almost 100% mortality in eggs. When egg rafts aged for 0, 4, 8, 12, and 24 h were exposed to 10 ppm neem suspensions for 36 h, the ovicidal activity was only attained in the egg rafts deposited directly (0 h old) in the neem suspension, not in those with ages of 4-24 h. On aging, depending on the formulations and mosquito species, the neem suspensions at 1 ppm completely lost ovicidal activity within 7-20 days. The egg rafts of Cx. quinquefasciatus were more susceptible to the test neem products than those of Cx. tarsalis. The formulated neem products were more persistent and effective than the technical AZ. The wettable powder (WP) formulation was slightly more persistent and effective than the emulsifiable concentrate (EC). The ovicidal activity of the neem products against mosquitoes from the current research clearly demonstrated the potential of neem products as possible ovicides against Culex mosquitoes.

Identification of antifungal compounds from the seed oil of Azadirachta Indica

Abstract: Evaluation of the activity of the cold expeller neem oil(Azadirachta indica A. Juss.) and the fractions derived through solvent partitioning, againstDrechslera oryzae, Fusarium oxysporum andAlternaria tenuis showed that the active antifungal fraction is a mixture of tetranortriterpenoids. Further, testing the triterpenoidal mixture derived from the 90% methanol (MeOH) extract of neem oil against 13 phytopathogenic fungi revealed that various species were inhibited to different degrees. Direct preparative High Performance Liquid Chromatography (HPLC) of the active fractions and subsequent bioassay of the semi-pure fractions indicated that the active fractions contained major compounds such as 6-deacetylnimbin, azadiradione, nimbin, salannin and epoxyazadiradione. Pure azadiradione, nimbin, salannin and epoxy-azadiradione did not have appreciable activity. However, when these terpenoids were mixed and bioassayed, they showed antifungal activity, indicating possible additive/synergistic effects.

Somatic embryogenesis and plant regeneration of neem (Azadirachta indica A. Juss.).

Abstract: Somatic embryos were initiated with mature seeds of neem (Azadirachta indica A. Juss.) when cultured on Murashige and Skoog's medium supplemented with thidiazuron (TDZ). Regeneration occurred via somatic embryogenesis: direct embryo formation and through an intermediary callus phase. TDZ was very effective and induced somatic embryogenesis across a wide range of concentrations (1–50 µm). However, somatic embryogenesis was accompanied by callus formation at concentrations of 20 µm and above. Cell suspension cultures were established with the TDZ-induced callus and groups of large cell clumps were formed within 2–3 weeks. Plants were regenerated from both directly formed somatic embryos and somatic embryos derived from cell suspensions plated on semisolid medium devoid of growth regulators. Regenerated plantlets continued to grow after transfer to a greenhouse environment and were similar phenotypically to zygotic seedlings. This simple regeneration system may be beneficial for mass propagation of selected elite clones of neem.

Possible biochemical mode of anti-inflammatory action of Azadirachta indica A. Juss. in rats.

Abstract: The water soluble part of alcoholic extract of A indica leaves at a dose of 200 mg/kg, po, exerted significant antiinflammatory activity in cotton pellet granuloma assay in rats The extract also inhibited significantly the biochemical parameters (viz DNA, RNA, lipid peroxide, acid phosphatase and alkaline phosphatase) studied in cotton pellet exudate

Evaluation of plant based formulations of trichoderma harzianum for the management of meloidogyne incognita on egg plant

Abstract: Aqueous extracts of neem (Azadirachta indica), castor (Ricinus communis) and pongamia (Pongamia pinnata) cakes were evaluated as substrates for mass production of the biological control agent, Trichoderma harzianum which was used in the management of Meloidogyne incognita in egg plant under fields conditions Castor cake extract at 10% gave maximum growth of mycelial mat and spore production of T harzianum compared with moderate growth in 10% pongamia cake and 5% castor cake extracts Application of plant based formulations of T harzianum to nursery beds of egg plant was effective in producing vigorous seedlings (increase in plant height and seedling weight) with the least root galling The above treatments also increased root colonization and parasitization of M incognita females by T harzianum

Contrasting seed storage behaviour among different species of Meliaceae

Abstract: Seeds of six species of Meliaceae were tested for germination following desiccation and subsequent hermetic storage for up to 26 months in different environments. Seeds of both Aglaia clarkii and Sandoricum koetjape were very sensitive to desiccation; no seeds survived desiccation to 20% moisture content or below. In contrast, stones of Melia azedarach survived desiccation to 3.5% moisture content and viability was maintained during 26 months' subsequent hermetic storage in 14 of the 15 environments which combined factorially five stone moisture contents between 3.5 and 11.7% with three temperatures between -20 °C and 10 °C, the exception being that environment which provided the highest moisture content and temperature (i.e 10 °C with 11.7% moisture content) in which loss in viability was considerable. Seeds of Azadirachta indica tolerated desiccation to moisture contents in equilibrium at 20 °C with 30-55% r.h. depending on seed lot, and a considerable proportion of seeds survived further desiccation to moisture contents in equilibrium with 6.5 to 30% r.h. Seeds of Swietenia macrophylla and Khaya senegalensis were more tolerant of desiccation than those of Azadirachta indica, but some loss in viability was detected on desiccation to moisture contents in equilibrium with 17% r.h. Moreover, the longevity of all three species in hermetic air-dry storage was shorter at cooler (-20 °C and 0 °C) than at warmer (10 °C) temperatures. We conclude that Aglaia clarkii and Sandoricum koetjape show recalcitrant seed storage behaviour, while Melia azedarach shows orthodox seed storage behaviour, but that Azadirachta indica, Khaya senegalensis and Swietenia macrophylla show intermediate seed storage behaviour. We illustrate how combining information on four criteria (seed weight, shape, moisture content at maturity, and plant ecology) may provide a guide to likely seed storage behaviour in Meliaceae.

Fungitoxic Activity of Extracts from Azadirachta indica and Xylopia aethiopica on Colletotrichum lindemuthianum in Cowpea

Abstract: Hot water and oil extracts of Azadirachta indica (neem) and Xylopia aethiopica significantly reduced spore germination and growth of Colletotrichum lindemuthianum in vitro. Tests with cowpea (Vigna unguiculata) indicated the extracts applied before or after infection of the plants with Colletotrichum lindemuthianum were also effective in reducing the size of pathogen induced lesions. The fungitoxicity of the extracts from Azadirachta indica and Xylopia aethiopica was greater than that of bonomyl.

Neem (Azadirachta indica) seed kernel extracts and azadirachtin as oviposition deterrents against the melon fly (Bactrocera cucurbitae) and the oriental fruit fly (Bactrocera dorsalis).

Abstract: Neem(Azadirachta indica A. Juss.) seed kernel (NSK) extracts,viz., NSK aqueous suspension (NSKS), ethanolic extract of NSK (EtOH. NSK), hexane extract of NSK (neem oil), ethanolic extract of the hexane extract (EtOH. oil) and acetone extract of deoiled NSK powder (Acet. DNSKP) at 1.25-20% concentrations, and pure azadirachtin at 1.25-10 ppm, were evaluated as oviposition deterrents toBactrocera cucurbitae (Coq.) andB. dorsalis Hendel. NSKS at ≥5% under choice test conditions, and at all concentrations (≥1.25%) in no-choice tests significantly deterred oviposition in both species. Similarly, EtOH. NSK was significantly active at all the concentrations tested for both species in choice and no-choice tests. However, with neem oil and EtOH. oil sensitivities of the two species differed considerably. Both extracts deterred oviposition byB. cucurbitae at all the concentrations tested under both choice and no-choice test conditions. On the other hand, withB. dorsalis, neem oil was significantly deterrent only at 20% in both test regimes and at 5% and 20% for EtOH. oil under choice and no-choice test conditions, respectively. Acet. DNSKP significantly deterred oviposition by both species at all concentrations tested. Azadirachtin failed to deter oviposition in either species.

Immunopotentiating effects of Azadirachta indica (Neem) dry leaves powder in broilers, naturally infected with IBD virus.

Abstract: Effects of feeding of powdered dry leaves of A. indica (AI) were investigated on humoral and cell mediated immune responses, in a flock of broilers which had survived an outbreak of infectious bursal disease (IBD). AI (2 g/kg) treatment significantly enhanced the antibody titres against new castle disease virus (NCDV) antigen and also potentiated the inflammatory reactions to 1. Chloro-2,4-di- nitro benzene (DNCB) inskin contact test. The results indicate that AI could be beneficial in immunosuppressed condition like IBD, in poultry.

Callus cultures ofAzadirachta indica and their potential for the production of Azadirachtin

Abstract: The content of azadirachtin, an insecticidally active ingredient in neem tree [Azadirachta indica (A. Juss.)] seeds, varies considerably due to environmental factors and for genetic reasons. Furthermore, the tree does not grow in moderate climates. It seems appropriate, therefore, to employ tissue culture techniques for the production of azadirachtin in order to obtain constant amounts of standardized quality. We investigated if and how azadirachtin contents of callus cultures derived from various cell lines are affected by different nutrient media and carbohydrate concentrations. The azadirachtin contents of the calli were analyzed by TLC and HPLC. Azadirachtin contents of callus cultures varied depending on the cell line, the nutrient medium and the carbohydrate source employed.

A standard procedure for the micropropagation of the neem tree (Azadirachta indica A. Juss).

Abstract: Micropropagated shoots were initiated from leaf explants of the neem tree, Azadirachta indica A. Juss. Regardless of their origin, shoots were successfully produced by culturing leaf explants on Murashige and Skoog medium containing benzylaminopurine (1 mg l–1), kinetin (0.8 mg l–1) and adenine sulphate (6 mg l–1) in complete darkness. These shoots were further multiplied on Murashige and Skoog medium containing benzylaminopurine (0.1 mg l–1), kinetin (0.08 g l–l) and adenine sulphate (0.6 mg l–1). Within 32 weeks, 80 shoots could be produced from a single leaf explant (10 mm×10 mm). Fifty-five percent of these shoots rooted on Murashige and Skoog medium containing indolebutyric acid (1 mg l–1) and all of these grew on transfer to soil.

Chemoreception of oviposition inhibiting terpenoids in the diamondback moth Plutella xylostella

Abstract: The effects of six terpenoids and two terpenoid containing extracts of the neem tree (Azadirachta indica A. Juss.) on oviposition by the diamondback moth (Plutella xylostella L., Yponomeutidae: Lepidoptera) were tested. Two drimane terpenoids, the sesquiterpenoid polygodial and the neem extract Margosan-O exerted significant inhibitory effects at the dosages tested. Ablation experiments showed that both antennae and fore-tarsi contributed to mediation of the inhibition by a drimane. Location of chemosensilla on prothoracic tarsi and ovipositor was examined by scanning electronmicroscopy. Electrophysiological recordings from ovipositor and tarsal taste sensilla showed that distilled water produced distinct responses from one neuron. In tarsal sensilla, ethanol and drimane solutions produced responses from two neurons, one of which might be the water cell that fired at a reduced rate. A drimane significantly decreased the responses of tarsal chemoreceptors to a cabbage leaf extract, which is a possible sensory mechanism leading to behavioural avoidance of this compound.

Antifeedancy of neem products containing Azadirachtin against Culex tarsalis and Culex quinquefasciatus (Diptera: Culicidae).

Abstract: In order to develop and utilize new botanical insecticides originating from neem (Azadirachta indica A. Juss) in mosquito control programs as a potential larvicide, the antifeedant activity of three formulations of neem against the larvae of Culex tarsalis Coquillett and Culex quinquefasciatus Say was investigated under laboratory conditions. A significant antifeedancy was indicated at 5 ppm and 10 ppm azadirachtin (AZ) for all formulations and both species. Within the test concentration range of AZ (1-10 ppm), 5 ppm was the minimum effective concentration for antifeedancy in most cases. Some differences in larval susceptibility in terms of antifeedancy to the test formulations were noted between the two species. The Cx. tarsalis larvae were more susceptible than Cx. quinquefasciatus larvae to Azad EC 4.5 at 1 ppm during the first 15-min exposure period and at 5 and 10 ppm during the whole test period. The Cx. quinquefasciatus larvae were more susceptible than Cx. tarsalis larvae to Azatin WP 4.5 at 1, 5, and 10 ppm during the first 15-min exposure period or to Neemix EC 4.5 at 1 ppm during the first 45-min exposure period. The formulation-related differences in antifeedant activity appeared when the concentration increased from 1 to 10 ppm. In Cx. tarsalis, the Azad EC 4.5 and Neemix EC 4.5 were more effective than Azatin WP 4.5 at 5 ppm during the first 15-min exposure period and at 10 ppm during the whole test period. In Cx. quinquefasciatus, the Azatin WP 4.5 and Neemix EC 4.5 were more effective than Azad EC 4.5 at 1 ppm during the first 30-min exposure period, and at 5 ppm during the first 60-min exposure period, and at 10 ppm during the whole test period.

Morphological and oil content variation in seeds of Azadirachta indica A. Juss. (Neem) from northern and western provenances of India.

Abstract: Seed morphology (seed length and 20 seed weight) and oil content was studied in Azadirachta indica A. Juss. (Neem) of five provenances of northern and western India. Trees with wide ranges of girths were considered for study. Maximum average oil content was observed in trees from Hisar provenance. Seed oil content in most of the provenances was not consistently and significantly correlated with morphological parameters of seeds. Age of the tree had no significant effect on the oil yield.

The toxicity of margosan-O, a product of neem seeds, to selected target and nontarget aquatic invertebrates

Abstract: Margosan-O, an insecticide formulated from extracts of neem tree (Azadirachta indica) seed kernels, besides being toxic, also has feeding, oviposition-deterring, and growth-inhibitory effects on insects. This product, registered in the United States for ornamental plants, has been proposed for food crop use. However, little information exists on its effects on aquatic organisms. This study investigated toxicity of Margosan-O to the mosquito Culex spp., a possible target species, and to nontarget species—two crustaceans, Daphnia magna, Hyalella azteca, and a dipteran, Chironomus riparius. The 48-h EC50 value of 105 mg L−1 for Culex spp. was significantly more toxic than for C. riparius (281 mg L−1), not significantly different from D. magna (125 mg L−1) but was significantly less toxic than for H. azteca (71 mg L−1). A concentration of 20–30 mg L−1 caused growth inhibitory effects in Culex spp. and C. riparius larvae and 40 and 84 mg L−1 affected growth and reproduction in H. azteca and D. magna, respectively. Margosan-O may not be suitable for mosquito control since the concentrations required to control emergence may have some nontarget effects. Alternatively, the agricultural application of Margosan-O is also not expected to reduce the survival or produce growth and reproductive effects in nontarget aquatic organisms. However, based on estimated concentrations of less than 10 mg L−1 in adjacent shallow bodies of water and recommendations for repeated applications, there should be concern that the threshold for chronic toxicity is too narrow.

Adventitious rooting in shoot cuttings of Azadirachta indica and Pongamia pinnata

Abstract: Adventitious rooting in shoot cuttings of neem (Azadirachta indica) and karanj (Pongamia pinnata) was investigated in different seasons. The influence of auxins and B-vitamins (neem only) was evaluated. Maximum rhizogenesis coincided with the emergence of new sprouts i.e. February (neem) and March (karanj). Considering both rooting percentage and root biomass, IBA was the most effective auxin tested. Compared to auxin free controls, IBA (1000 ppm in neem and 800 ppm in karanj) significantly increased adventitious rooting percentage (80 to 100 % respectively), the numbers of roots and root biomass for both species. In neem, B-vitamin treatment yielded 40–50% rooting for cuttings. This was significantly greater than rooting for controls but equivalent to IAA treatments. In neem, some of the cuttings treated with 2000–3000 ppm IBA had well developed root systems without any sprouts. In karanj, all auxin treatments promoted sprouting. The level of total soluble sugars in the rooting zone of neem and karanj was higher in non-rooted than rooted cuttings.

The use of piperonyl butoxide and MGK‐264 to improve the efficacy of some plant‐derived molluscicides

Abstract: Synergism of an oil of Azadirachta indica, a powdered extract of Allium sativum bulbs and an oleoresin of Zingiber officinale rhizomes by piperonyl butoxide and MGK-264 was studied against the snails Lymnaea acuminata and Indoplanorbis exustus. The active components of these plant-derived molluscicides, respectively azadirachtin, allicin and [6]gingerol, were also combined with these synergists. Both piperonyl butoxide and MGK-264 enhanced the toxicity of all of the test compounds. The response of snails to the synergised mixtures was both time- and dose-dependent. © 1998 Society of Chemical Industry

Differential cytotoxic effects of azadirachtin on Spodoptera frugiperda and mouse cultured cells

Abstract: Azadirachtin is a natural biopesticide extracted from the neem tree (Azadirachta indica); however, its safety to mammals is not well documented. This study examined the influence of azadirachtin on the proliferation and morphology of Spodoptera frugiperda insect cells (SF-9), and mouse erythroleukemia cells (MEL-GM 86). Cell kinetic studies conducted at 24 h intervals for 144 h showed that azadirachtin treatments (0.05, 0.20 and 0.50 μg/ml) inhibited cell multiplication of the SF-9 cells. This inhibitory effect was dose dependent. Conversely, azadirachtin at 30 μg/ml did not reduce MEL-GM 86 cell proliferation. SF- 9 cells displayed an increase in cell swelling and cell abnormalities after 48 h of treatment with azadirachtin, whereas no such changes were detected in MEL-GM 86 cells. A scanning electron microscope study revealed that treatment with an azadirachtin concentration as low as 0.10 μg/ml induced cell swelling and caused distortions on the cell surface ultrastructure of SF-9 cells characterized by blebbing and holes after 48 h of treatment. However, these effects were not seen in the azadirachtin-treated MEL- GM 86 cells.

A multifactorial study of conditions influencing longevity of neem (Azadirachta indica) seeds.

Abstract: The longevity of neem, Azadirachta indica, seeds from African Sahelian (Burkina Faso) and Asian (Sri Lanka) provenances was studied over two years of storage under different conditions of moisture and temperature. After drying to equilibrium moisture content (MC) at different relative humidities at 20°C, seeds were placed in open storage at 20°C or hermetically sealed in packets at temperatures ranging from −20 to +20°C. There was hardly any difference in storage behaviour between seed batches / lots, whatever their provenance. Seeds originating from mature yellow fruits lived longer than seeds from green or brown fruits. In all storage experiments with seeds having MCs ≥ 10%, viability was preserved best at 10−15°C, indicating that neem seed is chilling (and freezing) sensitive. There was no survival longer than 2 years under these conditions. At MCs of 4–8%, seeds were considerably more tolerant of low temperature storage and had 40–60% viability after 2 years at all temperatures tested (−20 to +20°C). However, the seeds were sensitive to imbibitional stress, which could be alleviated by imbibition at temperatures of 25–30°C or above. The difficult storage behaviour of neem seed seems to stem from: (1) the sensitivity to low temperatures at MCs ≥ 10%; (2) the extreme sensitivity to imbibitional stress after storage at ≤ 8% MC; (3) underestimation of the water activity due to the high oil content of the neem seeds, causing unexpected metabolic stress in the higher MC and temperature range.

Effect of five botanicals on oviposition, adult emergence and mortality of Callosobruchus maculatus Fabr. (Coleoptera: Bruchidae) infesting cowpea, Vigna unguiculata L. Walp.

Abstract: The effect of five botanicals, viz, pepper (Piper nigrum L.), annona (Annona reticulata L.), neem (Azadirachta indica A. Juss), chilli (Capsicum annurim L.) and lemon (Citrus limon L.) on oviposition, adult emergence and adult mortality of Callosobruchus maculatus F. was studied when cowpea, Vigna unguiculata L. Walp. seeds were treated with their dried leaf powders, except lemon where dried peels were used. Azadirachta indica gave significantly highest reduction in oviposition of C. maculatus (37.5%), followed by A. reticulata (39%) with 0.2 g concentration at 2 days after treatment (DAT). Again, A. indica significant reduction in adult emergence of C. maculatus (20.3%) with 0.2 g concentration at 30 DAT. In respect of adult mortality, 0.2 g of C. limon recorded highest mortality (8.3%) at 4 DAT and P. nigrum powder gave 8.25% mortality with 0.3 g of concentration, six days after treatment.

Effect Of Azadirachta Indica Leaf Extract On Carbontetrachloride - Induced Hepatic Damage In Albino Rats

Abstract: The shade dried leaves of Azadirachta indica were extracted successively by petroleum ether (60-80o) and ethanol. The ethanol extract after removal of solvent was studied for carbontetrachloride induced hepatic changes using 0.5 g and 1 g/kg oral dose in albino rats. The changes were assessed by serum enzyme profile that include glutamic oxaloacetate transaminase (GOT), glutamic pyruvic transaminase (GPT), alkaline phosphatase (AP), bilirubin (B) and hepatic triglycerides (HTG) levels, histological changes in liver and pentobarbitone sleeping time as a functional parameter. There was significant reversal of biochemical, histological and functional changes induced by carbon tetrachloride in rats by ethanol extract treatment.

Azadirachtin and nimbin content in in vitro cultured shoots and roots of azadirachta indica a. juss.

Abstract: From immature embryos of Azadirachta indica A. Juss, callus was developed with 100% response on MS medium supplemented with (a) 2.0 mg J-1 NAA + 0.5 mg 1·1 BA, (b) 2 mg J-1 BA and (c) 1.0 mg J-lAA + 0.5 mg J-1 BA. For optimum multiple shoot formation, medium containing (a) 2.0 mg )·1 BA and (b) 0.5 mg J·l BA + 0.1 kgl· NAA was used which rooted in 1/2 strength MS medium supplemented with 0.5 mgJ-1 IBA. Azadirachtin and nimbin content were analysed in callus, in vitro cultured roots and shoots. Roots had 0.004 mg/g azadirachtin and shoots had 0.008 mg/g azadirachtin and 0.003 mg/g nimbin. Callus had negligible amount of azadirachtin.