Azadirachta Indica Juss Research Articles

Biological control of fruit rot of postharvest orange (Citrus aurantium) by aqueous plant extracts

Post-harvest rot symptoms caused by complex airborne fungi are nowadays the most serious threatening disease affecting orange fruits in Nigeria and presumably in many African countries. Experimental trials were conducted at the Department of Biological Sciences (Akwa Ibom State, Nigeria) from January to December 2022 to ascertain the pathogens associated with postharvest fruit rot of oranges (Citrus aurantium L.). Results of the pathogenic test revealed that Fusarium sp. and Penicillium sp. are pathogenic and produced the highest lesion diameter (38.67 and 40.33 mm, respectively) and disease severity index (88.67 and 94.33%, respectively). The frequency occurrence of Fusarium sp. (69.14%) and Penicillium sp. (50.62%) was the highest. Two aqueous extracts of Azadirachta indica Juss. leaves and Zingiber officinale Roscoe rhizomes (at 80% concentration) were evaluated for their antifungal activities against the pathogenic isolates under in vitro and in vivo conditions. The results revealed that A. indica and Z. officinale aqueous extracts exhibited the highest mycelial growth inhibition (>90%) of Fusarium sp. and Penicillium sp. Similarly, under in vivo assay minimum lesion diameter (≤ 6.37 mm) and disease severity index (≤11.13%) were recorded in these aqueous extracts. In conclusion, the application of A. indica and Z. officinale can provide an alternative to fungicides against Penicillium sp. + Fusarium sp.

Comparative antifungal Evaluation of Azadirachta indica juss leaf extract against Rhizoctonia solani causing leaf blight of Turmeric

In the present study the aqueous and methanol leaves extracts of Azadirachta indica using different concentrations from 10 to 40% were tested in Vitro by following poisoned food technique against Rhizoctonia solani causing leaf blight of turmeric. The used concentrations of leaves extract were as 0.0 (control), 10, 20, 30 and 40%. The aqueous Azadirachta indica leaves extract at 30% concentration and methanolic leaves extract at 40% concentration were found to be best in reducing the mycelial growth of Rhizoctonia solani. Keywords: Azadirachta indica, Turmeric. Rhizoctonia solani.

Concentration Dependent Effect of Azadirachta indica (Neem) Seed Oil and Neem Bark extract on Planktonic and Established Biofilm Growth of Pseudomonas aeruginosa and Staphylococcus aureus

Azadirachta indica Juss (Neem) is well documented for its antimicrobial activity. The effect of varying concentrations (0.1 to 50% v/v) of Azadirachta indica derived neem seed oil (NSO), neem seed oil with tween 20 and neem bark extract was evaluated on planktonic, biofilm formation and mature biofilms of multiple drug resistant Pseudomonas aeruginosa ATCC 15442 and Staphylococcus aureus ATCC 25923 using the crystal violet assay and scanning electron microscopy. NSO showed antimicrobial activity at 25% v/v for P. aeruginosa but not S. aureus in zone of inhibition assay. Neem bark extract on the contrary showed antimicrobial activity against both the isolates at 50% v/v concentrations. Interestingly, in biofilm formation assay, low concentrations of NSO (3.5 to 0.2% v/v) induced biofilm formation while inhibition of both planktonic and biofilm was seen in concentration dependent manner from 12.5% v/v onwards. Complex of NSO and tween in comparison of NSO alone caused low induction in S.aureus biofilm formation, while inhibiting biofilm formation of P. aeruginosa at all the concentrations. In biofilm eradication assay, NSO induced biofilm of both P. aeruginosa (50 to 0.1%v/v) and S. aureus (50 to 3.13%v/v). Eradication effect of neem bark extract was found on P. aeruginosa biofilm in a dose dependent fashion from 50 to 20% v/v followed by 0.2 to 0.1%v/v concentration respectively. S. aureus biofilm were eradicated at 50 to 25%v/v concentrations. At low concentrations, both the neem derivatives induced biofilm mediated growth of the pathogenic organisms. The data also indicate that neem seed oil was more effective against Gram negative P. aeruginosa while neem bark extract was effective against Gram positive S. aureus. This study highlights the crucial but variable effects of concentration dependent effect of phytochemicals and their composition on biofilm induction as well as eradication, the primary growth form in clinical settings. This challenges the notion that all herbal products are safe as antimicrobial activities differ as per microbial growth modes. Hence, concentration dependent effect of medicinal plant derived products requires thorough investigation prior to their use as antimicrobial agents.

In vitro and in vivo study: Ethanolic extract leaves of Azadirachta indica Juss. variant of Indonesia and Philippines suppresses tumor growth of hepatocellular carcinoma by inhibiting IL-6/STAT3 signaling.

Background: Azadirachta indica Juss. has been shown to suppress cancer progression through a variety of mechanisms. In order to treat cancer progression, cancer immunotherapy is used to stimulate the immune system where immunosuppression is present in tumor microenvironments. Many cancer cells produce a lot of interleukin-6 (IL-6) and signal transducer activator of transcription 3 (STAT3). STAT3 plays a key role in suppressing the expression of critical immune activation regulators. IL-6-mediated STAT3 activation is common in the tumor microenvironment. Inhibiting the IL-6/STAT3 signaling pathway has become a therapeutic option for cancer progression. As vimentin is also expressed in hepatic stellate cells boosting cancer survival. We focused on the precise effect of extract from leaves of Azadirachta indica Juss, on inhibiting the IL-6/STAT3 signaling cascade on hepatocellular carcinoma by in vitro and in vivo study. Methods: In the in vitro study, the effect of Azadirachta indica Juss. variant Indonesia and Philippines against the expression of IL-6 and STAT3 was examined in liver cancer cell line. In the in vivo study, 24 male rats ( Rattus norvegicus) strain Wistar were induced by diethylnitrosamine and carbon tetrachloride (CCl 4). Based on the therapy given, the groups were divided into negative control, positive control, Indonesia extract, and Philippine extract. Expression of IL-6, STAT3, and vimentin were tested using immunohistochemistry staining. The data were analyzed using analysis of variance, which was then followed by the Tukey test. Results: Statistically significant difference in IL-6 and STAT3 was observed between the treatment groups and positive control group by in vitro study and in vivo study. Generally, there is no significant difference between treatment using Indonesian and Philippine leaves. Conclusion: Both therapy doses of Azadirachta indica variant in Indonesia and Philippines were able to reduce IL-6, STAT3 and vimentin expression of hepatocellular carcinoma cell by in vitro and in vivo experiment.

RESGATE VEGETATIVO DE Azadirachta indica POR ESTAQUIA

ABSTRACT Finding forest species adapted to different soil and climatic conditions and, that provide favorable attributes to commercial use is a challenge. Azadirachta indica is a potential species to attend to this goal. Thus, this paper aims to carry out the vegetative rescue of different Azadirachta indica Juss adult trees by cuttings. For that, Azadirachta indica individuals were randomly selected in a plantation of species set ten years ago and the cut was carried out at 30 cm in height. In sequence, verification was carried out on: (a) the stem cut ability to regrowth (collections and measurements of the shoot length on the 15th, 30th, 45th, and 60th days); (b) the need to use exogenous auxin for rooting induction [testing 0 (control), 2000, 4000, and 6000 mg.l-1 of Indole-3-butyric acid (IBA)]; (c) the ideal of the propagule size (with 8 cm and 13 cm in height); and (c) the rooting dynamics (every seven days for thirty-five days; the propagules were evaluated for callus formation, oxidation, and rooting). The species showed high regrowth ability, as well as easy rooting with or without the use of IBA; it was found that the ideal size for the propagule is 13 cm and that the process of rooting and root elongation is completed after thirty-five days of staking. The conclusion is: (a) using cuttings for the species vegetative rescue is interesting; (b) 13 cm is considered appropriate for the propagule size, and; (c) the aid of IBA at a dose of 2,000 mg L-1 is ideal to standardize rooting.

Phytochemical Screening of Selected Botanicals and their Effectiveness Against Maize Weevil (Sitophilus Zeamais Motsch.) at Paklihawa, Rupandehi, Nepal

Laboratory experiment was done to perform the phytochemical screening of six locally available botanicals (Azadirachta indica Juss, Artemisia dubia Wall, Lantana camara L, Parthenium hysterophorus L, Justicia adhatoda Linn. and Moringa oleifera L.) and their effectiveness to control the maize weevil (Sitophilus zeamais Motsch.) at Agriecology lab of Institute of Agriculture and Animal Science, Paklihawa Campus, Rupandehi, Nepal. Seven treatments (leaf extract of A. indica, A. dubia, L. camara, P. hysterophorus. J. adhatoda and M. oleifera and distilled water as control) applied at 3 different doses (0.5, 1 & 2g/50g seeds) were arranged in CRD design with 3 replications. Result of mortality test of maize weevil revealed that, at highest concentration of L. camara powder (T17- 2g/50 gm seeds) mortality of maize weevil was observed up to 85% at 45 DAT. Whereas number of damaged grain was lowest in T17 (L. camara powder- 2g/50 gm seeds). The effectiveness of botanicals was found to increase with increasing the concentration. Besides that, Justicia adhatoda (2g/50g seeds) and Artemisia dubia (1g/50g seeds) were also found as good candidates to use for the control of Sitophilus zeamais. Qualitative tests done for the presence of various phytochemicals showed that Azadirachta indica Juss and Artemisia dubia Wall. were found to contain most of the tested metabolites among all botanicals. Most of those phytochemicals were extracted by the aqueous solution rather than other 3 menstrums used (acetone, methanol and petroleum ether). Similarly, quantitative test revealed that percentage of alkaloid was found 18.01%, 17.78%, 17.75%, 11.58%, 8.20%, 6.78% and flavonoid15.32%, 13.63%, 12.86%, 11.36%, 7. 51% 2.85% respectively in L. camara L. P. hysterophorus L., J. adhatoda Linn., M. oleifera L., A. indica Juss. and A. dubia Wall. Leaf extract of L. camera found to contain highest percentage of alkaloid (18.01%) as well as flavonoid (15.32%). So, it was concluded that locally available botanicals extract reach in alkaloid and flavonoid may have insecticidal property and could be use as grain protectant against the maize weevil in cost effective and eco-friendly manner. However, application at proper dose is necessary to maintain the efficacy at higher level.

UTILIZATION OF NEMBA STEM AS AN ANTITUBERCULOSIS COMPARED WITH RIFAMPICIN AND ETAMBUTOL

Indonesia ranks third in the number of tuberculosis, after India and China. Treatment of tuberculosis takes a long time, and the lack of discipline in taking medication has caused the Mycobacterium tuberculosis to be resistant to many synthetic drugs that have been used so far. In contrast, the discovery of new synthetic drugs is very slow. Traditionally, neem bark (Azadirachta indica JUSS.) has been used to treat coughing up blood and phlegm, and the results of previous studies show that ethanol extract of neem bark in vitro can inhibit the growth of Mycobacterium tuberculosis. This study was conducted to determine the toxicity of neem bark extract, formulation of neem bark ethanol extract into tablet preparations, and the potential of this tablet preparation as anti-tuberculosis in vivo in animals. Neem bark extract was made by percolation using an ethanol extractor. Toxicity test was carried out in the form of an acute toxicity test on mice to calculate the LD50 value and histopathological observations of the liver, lungs, and intestines. The tablets were made by wet granulation. The potential test of tablet preparations as anti-tuberculosis was performed in vivo on animals infected with Mycobacterium tuberculosis H37Rv using a nebulizer. The results showed LD 50 = 11.85 ± 0.571, including mild toxic. The ethanolic extract of neem bark can be formulated into tablets using a 6% gelatin binder, Manihot starch and primojel as a binder, and a mixture of starch and lactose as a filler. Neem bark extract tablets can cure tuberculosis of experimental animals that have been infected with Mycobacterium tuberculosis H37RV, which is given a dose of 3 times a day two tablets (50 mg/tablet) for six weeks seen tuberculosis bacteria from +3 to negative, and a dose of 3 times a day once a day. Tablet looks from +3 to +1.

Effects of Maruca vitrata multi-nucleopolyhedrovirus and neem oil, Azadirachta indica Juss on the eggs of the cowpea pod borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae)

Cowpea, Vigna unguiculata (L.) Walp., is the most cultivated and consumed legume in West Africa and is typically attacked by several insect pests, including Maruca vitrata, leading to reduced yields. This study assessed under laboratory conditions the efficacy of neem oil and M. vitrata multi-nucleopolyhedrovirus (MaviMNPV) against M. vitrata eggs as alternatives to second generation pesticides. Hatching and mortality rates after biopesticide application of neem oil, MaviMNPV, and the two in combination reduced the egg viability by 89%, 84% and 91%, respectively. Moreover, the combination of MaviMNPV and neem oil induced 100% mortality among the hatched larvae, compared to 60% and 100% alone, respectively. Implications for using these biopesticides are discussed within an integrated pest management (IPM) context.

Environmental and antimicrobial properties of silver nanoparticles synthesized using Azadirachta indica Juss leaves extract

This study employs a green, eco-friendly and convenient hydrothermal method for the synthesis of stable silver nanoparticles (Ag NPs) using medically beneficial Azadirachta indica A. Juss leaf extract as reducing as well as capping agent. Careful optimization of hydrothermal conditions leads to the formation of spherical Ag NPs of size 9–15 nm. Thus, synthesized NPs are characterized by spectroscopy and microscopy techniques, revealing the morphology and size the NPs. The chemical composition and functionality of the plant extract and NPs is studied using FTIR and EDS analysis. The photocatalytic activity of Ag NPs is demonstrated by decolourization of Rose Bengal under visible light. Ag NPs also show bactericidal activity against E. coli, K. pneumonia, S. epidermidis and S. pneumoniae.

HPTLC fingerprinting and antimicrobial activity of Azadirachta indica leaf extracts

Azadirachta indica Juss which also Known as Neem plant used from ancient times for various human ailments as a traditional medicine. To appraise the scientific study for the use of Azadirachta indica, ethanolic extracts of the dried leaves of the plant were subjected to HPTLC finger printing and determination of anti-microbial activity of aqueous and ethanolic extract on five different species of bacteria and a fungus. The ethanolic extract of dried powdered leaves was evaluated by HPTLC finger printing using solvent system of Dichloromethane: ethanol (19:1) which exhibits the identity of different compounds present in the extracts. The antimicrobial activity of the concentrated extracts was evaluated by determination of the diameter of zone of inhibition against the microorganisms using agar well diffusion method. Both plant extracts had antimicrobial effects against the test organisms, however the aqueous extracts were found to show greater anti-microbial effect than ethanolic extract. Thus, the mean diameter zones of inhibition ranged from 0.04mm-50.00mm for aqueous extract and 0.40mm-20.00mm for ethanolic extract at the highest concentration of 50mg/ml. The finding of this study supports the use Azadirachta indica leaves and can be use in the treatment of various microbial infections as alternative systems of medicine.

Air pollution tolerance index of plants growing near an industrial site

Green vegetation around industrial premises can provide a cost-effective and eco-friendly technique to mitigate air pollution. Sensitive and tolerant plant species can be identified by evaluating their air pollution tolerance index (APTI). APTI is deduced by evaluating the pH, ascorbic acid, total chlorophyll, and relative water content (RWC) of plant leaves. An APTI score of ≤11, 12–16, and ≥17 classifies the tree species as sensitive, intermediate, and tolerant towards air pollution respectively. The present study was designed to estimate the air pollution tolerance index (APTI) of 25 plant species growing at Talkatora Industrial Area, Lucknow Uttar Pradesh, India. The biochemical properties of plant species ranged from; ascorbic acid: 0.6–19.6mg/g, RWC 41.34%–98.62%, pH4.5–8.2 and chlorophyll content 0.59–1.49mg/g. Findings revealed that among 25 plant species, Ficus bengalensis>Ficus religiosa>Eucalyptus globus>Azadirachta indica juss>Heveabra brasiliensis are tolerant towards air pollution; whereas, Polythalia longifolia was found to be most sensitive. In addition, the dust capturing potential of the plant leaves has also been evaluated. Moringa oleifera leaves were found to have the highest dust capturing potential (5.7mg/cm2), whereas, the lowest was noticed in Acacia nilotica (0.10mg/cm2). Pearson correlation of biochemical parameters revealed that ascorbic acid showed significant correlation (R2=0.897) with APTI. The species having <11 APTI values may be used as a bio-indicator of air quality, while those having APTI ≥17 can be used for green belt designing.

Antituberculosis and Toxicity Assay of ethanolic extract of Mimba Cortex (Azadirachta indica JUSS.)

According to WHO has identified so much people with tuberculosis disorder, and includes a disease that causes death. Mycobacterium tuberculosis has been resistant to antituberculosis drugs were used, while the discovery of new synthetic antituberculosis are very slow. Traditionally, mimba cortex has been used to treat cough and bloody sputum. In previous research proved that the ethanol extract of mimba cortex can inhibit the in vitro growth of Mycobacterium tuberculosis. This study was conducted to determine the potential of mimba cortex as antituberculosis in vivo and toxicity test. Antituberculosis potency test in vivo in guinea pigs infected with Mycobacterium tuberculosis H37Rv directly into the bronchi using nebulizer. Then given mimba cortex extract 3 times a day 100 mg/kgBW and 50 mg/kgBW. Isoniazid, Rifampicin and Ethambutol used as a comparison. Antituberculosis assessment examination conducted by Mycobacterium tuberculosis on bronchial fluid speciments were taken every two weeks and tested in culture with Lowenstein-Jensen method. Acute toxicity test conducted on mice, the LD50 value calculation and observation of liver, kidney, and lung histopathology. The result of research showed that the ethanol extract of mimba cortex have antituberculosis activity in guinea pigs which has infected with Mycobacterium tuberculosis H37Rv, 3 times daily dosing of 100 mg/kgBW for 6 weeks, showed that bacterium from +3 to negative, and 3 times daily dosing of 50mg/kgBW showed that bacterium from +3 to +1. Acute toxicity test results showed LD50 11.85 ± 0.571. That is including mild toxic category.Keywords: mimba cortex, antituberculosis activity, acute toxicity

Description of a new species of Phyllocoptruta (Acari: Eriophyoidea) on Azadirachta indica from West Bengal, India

A new species, Phyllocoptruta neemae sp. nov. of the family Eriophyidae was found on both surface of leaves of Azadirachta indica Juss (Meliaceae), and described and illustrated from specimens collected at Kalyani, West Bengal, India. This is the third eriophyoid mite species described from A. indica in India. The key of the Indian Phyllocoptruta species was given.

Combined activity of Maruca vitrata multi-nucleopolyhedrovirus, MaviMNPV, and oil from neem, Azadirachta indica Juss and Jatropha curcas L., for the control of cowpea pests

The insecticidal activity of Maruca vitrata (F.) multi-nucleopolyhedrovirus (MaviMNPV) combined with oil from neem, Azadirachta indica Juss and Jatropha curcas L. (Euphorbiaceae) was studied under laboratory and field conditions against three key insect pests of cowpea, Vigna unguiculata (L.) Walp. Second-instar Aphis craccivora Koch and Megalurothirps sjostedti Trybom nymphs, and third-instar M. vitrata larvae, all from laboratory colonies, were treated with various concentrations of one of the control agents separately or combined. Daily mortality was recorded for five days (A. craccivora and M. sjostedti nymphs) or fourteen days (M. vitrata) and the larval and pupal development as well as adult emergence were assessed. Combination of MaviMNPV resulted in a significantly higher larval mortality in M. vitrata than treatment with either virus or botanical insecticide alone at the corresponding concentrations. Larvae of M. vitrata infected with MaviMNPV and treated with botanical oils died sooner than those infected with only one control agent. Combinations of MaviMNPV and botanical oils produced additive or synergistic effects. No evidence of antagonistic effects was noted. In field experiments, the application of botanical insecticide and MaviMNPV either alone or in combination was effective in reducing insect abundance over the four weeks, and preventing yield loss. In the first field season, where the M. vitrata population was higher, the combination of the virus and either of the botanical pesticides induced significantly higher yields than spraying chemical insecticide. Application of MaviMNPV in combination with J. curcas and A. indica oil has proven to induce consistent MaviMNPV infection in M. vitrata populations. The combined application of MaviMNPV and botanical oils is discussed in the context of integrated pest management.

Development of anticorrosive two pack polyurethane coatings based on modified fatty amide of Azadirachta indica Juss oil cured at room temperature – a sustainable resource

We report the modification ofAzadirachta indicaJuss oil (renewable source) fatty amide by the piperazine molecule to develop a new polyol.

Synthesis, characterization and application of Azadirachta indica juss (neem oil) fatty amides (AIJFA) based polyurethanes coatings: A renewable novel approach

Number of diethanol amides has been developed by scientist using various vegetable oils and not from neem seed oil. Most of the research work on neem seed oil has explored its applications in pharmaceutical and pesticides fields. This paper representing new area of application of neem seed oil for polymeric resin, in which we attempted to synthesize the neem seed oil based poly(urethane fatty amides) by reaction of neem oil fatty amide (AIJFA) with trimer of isophorone diisocyanate (IPDI). Spectral study of AIJFA was carried out by using FT-IR and 1H NMR techniques. Molecular weight of AIJFA was determined by gel permeation chromatography (GPC). Fatty acid composition of neem seed oil was obtained by gas chromatographic method. The coatings applied on mild steel plates were evaluated by determining coating properties, chemical and corrosion resistances. TGA study of coatings showed higher thermal stability to AIJFA based PU coatings compared to normal urethane and alkyd coatings.

Aqueous fruit extracts of Azadirachta indica induce systemic acquired resistance in barley against Drechslera graminea

The study reported here primarily focuses on whether fruit extracts of Azadirachta indica Juss. (Neem) can induce systemic acquired resistance (SAR) in Hordeum vulgare against Drechslera graminea. A single leaf from each of the 1-month-old seedlings grown in 50 pots was treated with neem extract. Seven samples were collected at 12-h intervals for estimation of salicylic acid (SA) content and activities of phenylalanine ammonia lyase (PAL) and peroxidase (PO). Disease incidence was recorded on uninoculated leaves after 2 weeks and on newly emerged leaves after 3 weeks of inoculation of spores of the pathogen. Treatment of single leaf of barley seedlings with aqueous fruit extract of neem could protect the untreated and later emerging leaves of these seedlings from infection by leaf stripe pathogen. The concentration of SA and activities of PAL and PO were significantly higher in untreated leaves of seedlings given a single leaf treatment with neem fruit extract. The results show that neem fruit extract induced SAR in barley seedlings against D. graminea. The results of the study are significant for developing an environment-friendly biocide, which could induce SAR in crop plants leading to efficient management of pathogens

The comparative efficacy of some botanicals for the control of the seed weevil Caryedon serratus Olivier (Col., Bruchidae) in seeds of Acacia seyal Del.

A comparative study on the efficacy of powder and oil extracts from leaves and seed kernels of Azadirachta indica Juss. and Eucalyptus camaldulensis Dehn. against the seed weevil Caryedon serratus Olivier infesting seeds of Acacia seyal Del. was carried out. EO 1, EO 5 and NSKO5% were comparable to BHC 3% in significantly reducing egg laying by C. serratus. With the exception of ELP and NLP, all botanicals significantly reduced egg hatching. Botanicals significantly reduced larval development with the exception of ELP and NLP. EO and NSKO at 3 and 5% were significantly more effective than BHC in reducing larval development by 95–97%. All botanicals had no significant effect on adult emergence which was only affected by BHC. Botanicals caused 4.3–43% mortality of C. serratus adults and the maximum mortality occurred in EO 3% as compared to BHC. It is apparent that oils extracted from E. camaldulensis had a fumigant and knock down effect on adult C. serratus. Extracted oils were more effective than leaf or seed powder. Oils extracted from leaves of E. camaldulensis were volatile and had a knock down effect on adult C. serratus indicating the possibility of using them as alternative fumigants in seed stores.

Purification of Azadirachta indica Seed Cake and Its Impact on Nutritional and Antinutritional Factors

Azadirachta indica Juss. (family Meliaceae) is a vital plant with multiple agricultural and medicinal utilities. The seed cake after oil extraction can be a good source of nutrition in animal feed. The limitation to its use is the presence of azadirachtin, salannin, and other bitter constituents. To make it palatable for use as a source of animal nutrition it was detoxified using 50 and 80% methanol and was analyzed for contents of azadirachtin, salannin, and nutritional contents such as total carbohydrates, protein, crude fiber, in vitro protein digestibility, and trypsin inhibitor activity (TIA), prior to and after purification. The contents of azadirachtin and salannin were quantified using HPTLC and HPLC. Various validation parameters were also investigated. A highly significant decrease of antinutritional factor (TIA) was recorded after purification of samples, retaining the contents of protein, carbohydrates, crude fiber, and in vitro protein digestibility. The purified seed cake was found to be free of azadirachtin and salannin contents.

Effects of an aqueous extract of Azadirachta indica on the growth of larvae and development of pupae of Culex quinquefasciatus.

The neem tree Azadirachta indica Juss (Meliaceae) is one of the most studied plant species for pest control, including mosquitoes. However, the effect of aqueous neem seed extracts (ANSE) on each of the 4 instars of mosquito Culex quinquefasciatus Say (Diptera: Culicidae) is unknown. In order to determine the effect of applying ANSE on the growth of each of the 4 larval instars and pupal stage of C. quinquefasciatus , 8 bioassays with ANSE concentrations ranging from 30 to 1000 ppm were applied to larvae of 1st, 2nd, 3rd and 4th instars. The experimental unit consisted of a plastic cup with 100 ml of water and 20 larvae. 1 ml of the different concentrations of ANSE was applied. Mortality was assessed when 93 to 98% of the larvae reached the pupae stage in the control. In the surviving population the duration of larval stages and pupae viability were recorded. The growth of larvae and development of pupae was recorded to determine a growth inhibition index (GII) and a relative growth index (RGI), which was used to calculate the EC