The efficacy of Azadirachta indica leaf powder and ethanol extract on adult Periplanata americana under laboratory condition to control the nuisance of the pest. The mean mortality count of adult Periplanata americana was the highest (92) in 50 g leaf powder and the lowest (2) in the control. The result also showed that the highest mortality (125) was recorded in 96 hr exposure time while the lowest (28) was recorded in 24 h exposure time. The Analysis of Variance (ANOVA) for the mean mortality in the experiment and the control indicated that there was significant difference (P-value = 0.05) in the mortality with increase in grams and exposure time of leaf powder and the control at 5% level of significance the mean mortality count of adult P. americana was the highest (108) in 50 ml ethanoic extract an d the lowest (3) in the control. The result also showed that the highest mortality (144) was recorded in 96 hr exposure time while the lowest (66) was recorded in 24 h exposure time. The Analysis of Variance (ANOVA) for the mean mortality in the experiment and the control indicates that there is significant difference (P-value = 0.05) in the mortality with increase in grams and exposure time of leaf powder and the control at 5% level of significance. The efficacy of Azadirachta indica Ethanol extract is more than the leaf powder. There was significant difference in mortality in both increase in concentration levels and exposure time at 5% level of significance in both leaf powder and ethanol extract.
The Neem tree, of the Meliaceae family, is a tropical evergreen plant related to mahogany and found in tropical nations [
Neem plant measures about 12 - 18 metres in height with a circumference up to 1.8 - 2.4 metres; a flowering plant which produces flower at 3 - 5 years of age [
Azadirachtin is the principal active compound in neem. It is a bitter, complex chemical that is both a feeding deterrent and a growth regulator. Other chemical components of neem include meliantriol, salannin, Nimbin, Nimbidin and other minor components which are also active against insect pests in various ways such as repellents, antifeedants and insecticides. Neem leaf and its constituents have been demonstrated to exhibit immune-modulatory, anti-inflammatory, anti-hyperglycaemic, antiulcer, antimalarial, antifungal, antibacterial, antioxidant, anti-mutagenic and anti-carcinogenic properties. A fraction of Neem oil called Nim-76 was reported to evoke spermicidal activity which makes it suitable for use as pre-coital antifertility formulation for human use, which has undergone phase one clinical trials [
Naturally occurring biopesticide could be an alternative for chemical pesticides. Almost every part of the neem tree has beneficial properties. Water extracts of neem twigs inhibited growth of dental caries organisms Streptococcus mutans, S. salivarius, S. mitis, and S. sanguis. Neem extracts have been reported to possess antibacterial, antifungal, antimalarial, and antiviral properties. Neem leaves are used in India for curing diarrhea and cholera. In addition, neem oil and leaves are used in popular medicine as antiparasitic, anti-inflammatory, antiulcer, antihyperglycemic, anticarcinogenic, and immunomodulatory agents [
Neem extract is composed of a complex mixture of molecules, including normal hydrocarbons, phenolic compounds, terpenoids, alkaloids, and glycosides [
The neem plant is very important and of high benefits thus solving many problems. The use of Neem, cannot be overemphasized, it is used basically as drugs, ornament for the treatment of various skin infections such as chronic wound infection, eczema, ringworm, acne, diabetic foot, athlete foot and gas gangrene [
Another traditional use of A. indica has been to chew the A. indica sticks. It is still used to clean teeth in rural parts of India. Antimicrobial properties help to reduce plaque and gingivitis. People used A. indica twigs as tooth brushes for centuries. A. indica twigs contain antiseptic ingredients necessary for dental hygiene and prevents tooth decay, periodontal diseases, infections, bleeding gums and sore gums [
Plate 1. A. indica tree.
with wound healing in multiple processes. It has a high content of essential fatty acids which is important in its role for adding moisture and a soft texture to the skin during the healing process. The leaf extracts and seed oil of the tree has proven anti-microbial effect. This keeps wound or lesion free from infection by bacteria, viruses, parasites and fungi. Clinical studies have also shown that A. indica plays another important role in wound healing by inhibiting inflammation as effectively as cortisone acetate [
With its extremely bitter properties, A. indica has been a corner stone of Ayurvedic therapy for pitas, or disorders caused by over eating sweets and in the treatment of diabetes [
Neem oil is used to prevent aflatoxin which is produced by Aspergillus flavus due to contamination of the poultry feed and the neem leaf extract antagonizes the production of Patulin caused by Penicillium expansium. The processed neem cake poses good appetizer characteristic together with wormicidal activity which is used as poultry feed. Furthermore, neem leaf has significant amount of protein, minerals (except Zinc) and digestible amounts of crude protein and total digestible proteins which served as better nutrition to the poultry animals such as goat, sheep and cow [
Neem cake residue upon extraction of neem oil from the seed is used as bio-fertilizer for nourishing plants and increasing crop yield [
The specific use of Neem in India for natural crop potential has extended world-wide over the past number of years, including a great number of countries where it is being sold commercially. The production of insecticides of Neem leaves can be done in a relatively simple, artisanal way or else as an industrial process. Studies indicate that the active substances of Neem (Azadirachtin, Salannin, Nimbin, Nimbidin and Meliantriol) have repellent, antifeedant and insecticidal effects against a number of insect pests [
Neem extract is composed of a complex mixture of molecules, including normal hydrocarbons, phenolic compounds, terpenoids, alkaloids, and glycosides [
The threat of insects and other pests particularly cockroaches, is well known and have been a challenge to man. Cockroaches are the most abundant insect pest of public health importance; they infest hospitals, food manufacturing industries, kitchens and residential apartments [
Cockroaches (Plate 2) are the most persistent pest to have colonized the planet. Since their origin, not only do they present a variety of health hazard when found in our houses, but are also a threat in commercial places, spreading diseases through any food source, that they come in contact with [
Plate 2. The American cockroach; Periplaneta americana.
only dirty and filthy but carries an odor which is offensive to the nose, and can contaminate food substances [
The ancient man had deployed different methods of control, including prayers, magic spells, cultivation systems, mechanical practices as well as application of organic and inorganic substances [
Developing countries and Nigeria in particular face the most challenges in achieving the sound management of pesticides. A large proportion of the population in Nigeria is directly engaged in agricultural work, often on a very small scale. While evidences abound that botanical pesticides are generally safe and effective [
From the foregoing, the need to advocate for and implement integrated pest management strategies both on field pests, storage product pests, structural pests and domestic pests is indispensable. Therefore the discovery advocating for the adoption and promotion of the use of bio pesticides like neem plant (A. indica) in an integrated pest management frame work is quite relevant. There has been evident shift all over the world from synthetic pesticides to non-synthetic ones; largely due to the wide spread awareness of the side effects of these synthetic pesticides on plants, soil and other living organisms. Plant extracts have been used worldwide as an alternative method to control pests unlike synthetic pesticide. Single plant derived compound may have more than one biological effect [
Fresh leaves of Azadirachta indica were collected form Amassoma Town in Southern Ijaw Local Government Area, Bayelsa State, Nigeria. They were identified at the herbarium of the University of Port Harcourt, Rivers State, Nigeria. The leaves of Azadirachta indica were separated manually. The plant leaves were oven dried under the temperature of 60˚C overnight [
For the extract, 1.5 kg of the powder was mixed with 2.8 liters of Ethanol and the mixture was allowed to stand overnight in the refrigerator. The following morning, this mixture was blended and filtered. The filtrate was evaporated using a desiccator and the resultant yield was 60 g of the extract which was about 4% yield. This was preserved in the refrigerator at 40c until ready for use. The total of Two hundred and forty (240) adult American cockroach used for the experiment were reared in a plastic container under ambient laboratory temperature of 30˚C ± 3˚C and 75% ± 3%. P. americana was fed with bread crumbs. One hundred P. americana were introduced into each treatment. All Treatments were arranged in completely randomized design (C.R.D).
Data Collection and Statistical Analysis Data were generated and recorded from mortality count of adult P americana at 24, 48, 72, 96 hrs and were used to determine the most efficient proportions of the powders. Dead weevils were removed and discarded after every count. Data generated on mortality of the weevils due to efficacy of leaf powders were subjected to analysis of variance (ANOVA) using SPSS computer Software package (version 20) at 0.05 significant levels.
The mean mortality of adult Periplanata americana exposed to Azadirachta indica leaf powder is presented in
The mean mortality of adult P. americana exposed to Azadirachta indica ethanoic extract is presented in
Leaf Powder Quantity (g) | Exposure Time (Hrs) | |||||
---|---|---|---|---|---|---|
24 | 48 | 72 | 96 | TOTAL | MN ± S.E | |
00 | 0 | 0 | 1 | 1 | 2 | 0.5 ± 0.3 |
10 | 0 | 5 | 13 | 18 | 36 | 9.0 ± 4.0 |
20 | 2 | 13 | 17 | 22 | 54 | 13.5 ± 4.3 |
30 | 5 | 15 | 21 | 26 | 67 | 16.8 ± 4.5 |
40 | 9 | 17 | 25 | 28 | 79 | 19.8 ± 4.3 |
50 | 12 | 22 | 28 | 30 | 92 | 23.0 ± 4.0 |
TOTAL | 28 | 72 | 105 | 125 | 330 | |
MN ± S.E | 4.67 ± 2.03 | 12.0 ± 3.31 | 17.5 ± 3.96 | 20.8 ± 4.34 |
Descriptive statistics | ANOVA | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Groups | Sample size | Sum | Mean | Variance | Source of Variation | d.f. | SS | MS | F | p-value | |||
24 Hr | 6 | 28. | 4.67 | 24.67 | Between Groups | 3 | 898.83 | 299.61 | 4.03 | 0.02 | |||
48 Hr | 6 | 72. | 12. | 65.6 | Within Groups | 20 | 1487.67 | 74.38 | |||||
76 Hr | 6 | 105. | 17.5 | 94.3 | Total | 23 | 2386.5 | ||||||
92 Hr | 6 | 125. | 20.83 | 112.97 | Residual standard error | 8.62 | |||||||
Total | 24 | 15.46 | 111.48 | Hartley Fmax (d.f. = 4, 5) | 4.58 | ||||||||
Cochran C (d.f. = 4, 5) | 0.38 | ||||||||||||
Bartlett Chi-square (d.f. = 3) | 2.65 | ||||||||||||
Ethanoic Leaf Extract (ml) | Exposure Time (Hrs) | ||||||
---|---|---|---|---|---|---|---|
24 | 48 | 72 | 96 | TOTAL | MN ± S.E | ||
00 | 0 | 1 | 1 | 1 | 3 | 0.8 ± 0.3 | |
10 | 7 | 12 | 19 | 25 | 63 | 15.3 ± 3.9 | |
20 | 9 | 15 | 20 | 28 | 72 | 18.0 ± 4.0 | |
30 | 12 | 23 | 27 | 30 | 92 | 23.0 ± 3.9 | |
40 | 18 | 25 | 29 | 30 | 102 | 24.8 ± 3.4 | |
50 | 20 | 28 | 30 | 30 | 108 | 26.8 ± 2.6 | |
TOTAL | 66 | 104 | 126 | 144 | 440 | ||
MN ± S.E | 10.3 ± 2.7 | 17.3 ± 4.1 | 21.0 ± 4.4 | 24.0 ± 4.7 | |||
Descriptive statistics | ANOVA | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Groups | Sample size | Sum | Mean | Variance | Source of Variation | d.f. | SS | MS | F | p-value | ||
24 Hr | 6 | 63. | 10.5 | 47.5 | Between Groups | 3 | 629.79 | 209.93 | 2.12 | 0.13 | ||
48 Hr | 6 | 106. | 17.67 | 99.87 | Within Groups | 20 | 1982.17 | 99.11 | ||||
76 Hr | 6 | 130. | 21.67 | 118.27 | Total | 23 | 2611.96 | |||||
92 Hr | 6 | 144. | 24. | 130.8 | Residual standard error | 9.96 | ||||||
Total | 24 | 18.46 | 113.56 | Hartley Fmax (d.f. = 4, 5) | 2.75 | |||||||
Cochran C (d.f. = 4, 5) | 0.33 | |||||||||||
Bartlett Chi-square (d.f. = 3) | 1.26 | |||||||||||
Result of the present study showed that the mortality of P. americana exposed to A. indica leaf powder increased with increase in grams and exposure time. Similarly, the mortality of P. americana exposed to A. indica ethanoic extract also increased with increase in concentration levels and exposure time. The result compared favourably with results from similar studies. Akunne et al. [
Raguraman and Singh [
Brisibe et al. [
Ofuya et al. [
Mondal and Mondal [
A. indica pesticides play a vital role in pest management and hence have been widely used in Agriculture for its safety and efficacy as bio pesticides [
Azadirachtin reduces insect feeding and acts as a repellent. It also interferes with insect hormone systems, making it harder for insects to grow and lay eggs. Neem oil is reportedly used to control the following pests: garden snails and slugs, cockroaches, bed bugs, scabies, dust mites, ants, fleas, ticks, fruit fly, whiteflies, Japanese beetles, cherry slug, pear slug [
Extracts from the neem tree are also used as repellents (the wood of the neem tree is strong and resistant to termite damage, used as mosquito repellents and as firewood for charcoal making), fumigant, pesticides (the leaves act as a natural pesticide), fertilizers, manure (neem leaves and the cakes gotten when oil has been removed from seeds can improve soil structure and add to the plant nutrient base), diabetic food and animal feed, urea coating agent and soil conditioner (neem leaves can be used to make soil less acidic) [
Plant extracts have been used worldwide as an alternative method to control pests unlike synthetic pesticide which have one active compound, and exhibit only one type of biological effect. Single plant derived compound may have more than one biological effect [
Laboratory experiments were conducted to study the insecticidal properties of Neem extract. Powders, liquid prepared from various neem parts (seed, leaf, stem, and root) against the macrotermes species phaseolus, Periplaneta specie and larvae of Anopheles species which are important pests of agriculture and public health [
A. indica leaf powder and ethanol extract are very effective in the control of Periplanata americana and other insect pests. The ethanol extract is however more effective than the leaf powder and should be recommended for controlling the menace of American coachroach since it is void of adverse environmental pollution. To solve the menace of cockroaches, effort should be geared towards applying A. indica leaf powder or its ethanoic extract to safeguard the adverse effects of conventional pesticides. Furthermore, A. indica is cheap and readily available. However, further research is required to determine the efficacy of the neem using higher concentrations and on a wide range of other common insect pests.
Rosemary, U.B., Nestor, A.J.F. and Abalis, O.R. (2018) Efficacy of Azadirachta indica Leaf Powder and Ethanol Extract on Adult Periplanata americana under Laboratory Condition. Open Access Library Journal, 5: e4458. https://doi.org/10.4236/oalib.1104458