Published on International Journal of Agriculture & Agribusiness
ISSN: 2391-3991, Volume 2, Issue 2, page 19 – 24
Publication Date: March 4, 2019
Khin Myint Mar
Associate Professor, Department of Zoology
University of Magway
The experiment was carried out the efficacy of crude extracts of Annona squamosa leaves for the control of the larvae of common major pest, Tobacco caterpillar Spodoptera litura in the Department of Zoology, University of Magway, Myanmar during October 2014 to March 2015. The leaves of fresh Annona squamosa were crushed and strained by filter paper to obtain crude extracts and then diluted with the distilled water to treatment percent. The adult specimens of Spodoptera litura were collected from groundnut and tomato fields in Magway environs cultured in the laboratory with food plants to be reared for larval stages. The 4th instar larvae of S.litura were tested with spraying method of A.squamosa leaves extract with only distilled water (control), 60%, 75% and 90% respectively. Three replications of ten larvae were tested for each treatment. The results showed that the mortality rate of Spodoptera litura was the highest (33.33% mortality) at 90% A.squamosa leaves crude extracts while the lowest at 60% (0% mortality) and the moderate (20% mortality) at 75% at room temperature of about 26.2˚C. The results from the experiment showed that the insecticidal activities of A.squamosa leaves on the larvae tested was the most effective at the concentration of 90% crude extract. Leave extract of A.squamosa is a promising candidate for development as simple botanical insecticide for local use in rural Myanmar.
Keywords: Annona squamosa, Crude extract, 4th instar Larvae, mortality, Spodoptera litura.
The indiscriminate use of chemical pesticides has given to many serious problems such as intoxication of people and animals, environmental pollution, residues on food, high persistence in the environment and impact on beneficial insects, among other effects, including genetic resistance of pest species, toxic residues, increasing costs of application, environmental pollution and hazards. With a greater awareness of the hazards associated with the use of synthetic organic pesticides, there has been an urgent need to explore suitable alternative products for pest control. This is a world-wide interest in the development of alternative strategies including the search for new types of insecticides and used for traditional botanical pest control agents. Plant crude extracts often consist of complex mixtures of compounds which may act synergistically (Berenbaum, 1985) and are highly effective, safe and ecologically acceptable (Senthil Nathan and Kalaivani, 2005) (cited by Baskar et al., 2011).
Plants are rich sources of natural substances that can be utilized in the development of environmentally safe methods for insect control. Numerous plant species have been identified as possessing pesticidal properties and have shown potential as alternative to chemical pesticides (Singh, 2000). More than 2000 plants species have been known to produce chemical factor and metabolites of value in pests control programme (Sreeletha and Geetha, 2012). Plant derived pesticides are eco-friendly, non-toxic to non-target organisms, non-persistent in nature, besides they do promote drug resistance (Kandagal and Khetagoudar, 2013). In fact, botanical pesticides from many plant origins including Annona squamosa and neem are in use in Indian agriculture for over a century to minimize losses caused by pests and diseases (Prakash, 2008). The phytochemical constituents in the leaves of Annona squamosa contain alkaloids, protein, amino acid, carbohydrate, glysides, phytosteroles, tanins and phenolic compounds (Kumar et al., 2010). Annona squamosa leaf content was possibility effective as insecticides or repellent is borneol. Borneol is an essential oil with bicyclic organic compound that belong to essential oil, and has a natural insect repellent effect. It has not been yet known how the about the mechanism of mechanisms work borneol as insect repellent (Kesetyaningsih, 2012).
Among the polyphagous pests, the tobacco caterpillar Spodoptera litura Fabricius (1775) is a serious pest of various economically important crops such as cotton, groundnut, chilli, tobacoo, caster, oil seeds, vegetables, bendy and pulses etc. The fully grown caterpillars are most voracious feeders and can cause extensive damage by defoliation. It has the ability to develop resistance to many conventional insecticides used for its control (Deshmukhe et al., 2010).
Myanmar is an agricultural country. The agricultural sector accounts for 34% of its gross domestic products (GDP) and 15.4 % of total export earnings. It also employs 61.2% of the total labor force. The importance of agriculture in Myanmar is underscored by the stated objective of having agricultural as the base of the country economy and the engine for the overall development of other sectors (Kan Zaw et al., 1998). In Myanmar, most of the researchers studied the tobacco and neem based pesticides used in the experiments and the research conducted with Annona squamosa as insecticides was very limited. The present study involves the application of A. squamosa (sugar apple) leaves crude extracts to study its effects on the mortality of Tobacco caterpillar at certain stage of development. In the present study, the larvae of Tobacco caterpillar Spodoptera litura were tested with the application of Annona squamosa (sugar apple) leaves crude extract as botanical pesticides. Therefore, the objective of the present study was to evaluate the insecticidal efficacy of the crude extract of Annona squamosa leaves on Spodoptera litura.
2. REVIEW OF LITERATURE
Karunaratne and Arukwatta (2009) have published efficacy of three plants species on the mortality and food consumption of Epilachna vigntioctopunctata. They reported the comparison of Annona squamosa leaf extract with the other two plants extract, it was very strong antifeedant effect on the larvae at all concentrations tested. Among the three plants tested, Annona squamosa was the most effective against the Epilachna larvae causing significantly very high mortality even after 24 hours.
Deshmukhe et al. (2010) recorded bioefficacy of cold ethly alchol extract of Annona squamosa against Spodoptea litura Fabricius. They observed the use of plant extracts to manage Spodoptea litura as an eco-friendly management strategy in organic farming, the need of the day. The result showed that the larvae which were administered the plant extract through their food showed total mortality of 76.66 ± 4.41 at 25% concentration, of which 61.66 ± 1.66% was at the larval stage itself.
Kumar et al. (2010) described insecticidal activity of ethanolic extract of leaves of Annona squamosa in which it showed potent activity against Sitophilus oryzae pest.
Sreeletha and Geetha (2012) published the pesticidal effects of Annona squamosa L. on male Oryctes rhinoceros Linn. in relation to reproduction. In which the pesticidal effect of Annona squamosa L. leaves on the fat body and testis of Oryctes rhinoceros Linn. was studied by incorporating the leaf powder along with the culture medium, cow dung. 50% larval mortality, 20% pupal mortality and 20% abnormal adult formation of O.rhinoceros were in 20% w/w proportion of leaf powder cow dung mixture and 30%, 20% and 20% and 10% w/w of it respectively.
Leatemia and Isman (2014) described toxicity and antifeedant activity of crude seed extract of Annona squamosa (Annonaceae) against Lepidopteran pests and natural enemies. They recorded that crude aqueous seed extracts of Annona squamosa had moderate to high toxicity to O. insidosus. In which the use of A. squamosa seed extract was used in conjunction with biocontrol agent for pest management.
Online information Services For Non-chemical Pest Management in the Tropics (Oisat, 2015) inform pesticidal effect of Annona squamosa leaves crude extract on Spodoptera litura, Spodoptera exigua, Phenacoccus solenopsis and detailed procedure for preparation of crude aqueous extract.
3. MATERIALS AND METHODS
The experiment was conducted in the Department of Zoology, University of Magway, Myanmar. The adult specimens of Spodoptera litura were collected from groundnut and tomato fields in Magway environs. Then, they were cultured in the laboratory with food plant to be reared for larval stages. 4th instar larvae were used to test. Experiment was carried out from October to December 2014.
3.1 Preparation of Annona squamosa leaves crude extract
The fresh leaves of the plant Annona squamosa (sugar apple) were collected from the home gardens near the campus of Magway University. The 100g of fresh leaves were washed with running tap water to clean dust and other particles. Then, the fresh leaves of A.squamosa were crushed by using a pestle and filtered the pulp by using filter paper for liquid of crude extracts. Different concentrations of A.squamosa leaves extract (60%, 75%, and 90%) with their respective dosage were applied to be evaluated their effects against the 4th instar larvae of Tobacco caterpillar under laboratory condition. In the extract method of A.squamosa, any chemical was not used.
3.2 Experimental Design
A contact bioassay was used to test the insecticidal activity of Annona squamosa leaves extract. The 4th instar larvae of Tobacco caterpillar Spodoptera litura were treated with the concentration of Annona squamosa leaves extract. Three replicates for each concentration (60%, 75%, and 90%) were made for five day period and control treated only with distilled water. Then, ten larvae of tested insects were introduced into the glass petri-dish 12 cm in diameter. Then, the food leaves were washed with tap water and added into the dish. The larvae of tested pests sprayed with the A.squamosa leave crude extracts were introduced into the dish prepared. Mortality was tested every 24 h after the treatment and recorded at room temperature. The mortality was determined under the dissecting microscope when they did not respond to mechanical stimulation.