Published on International Journal of Agriculture & Agribusiness
Publication Date: April 15, 2019
Khin Myint Mar
Associate Professor, Department of Zoology
University of Magway
This study was conducted to test the insecticidal and repellant activities of sugar apple leave extract against stored grain pest Tribolium castaneum (Herbst) during December 2018 to March 2019. The objectives of the study were to test the repellency of sugar apple extract against red flour beetle and to observe the mortality of beetle under the laboratory condition. 50g of dried leaves powder of sugar apple was soaked in the one liter of pure water for 24h at room temperature to obtain 5 percent concentration. In this experiment, the activity of 48.72 % when observed at the end of 24 h treatment, decreased to about 40.54% and 41.18 % respectively at the end of 48 h and 96 treatment. The extract of sugar apple leaves showed the highest level of repellant activity at the end of 72 h treatment. After 96 h of treatment, percentage of repellency was decreased about 41.18 %. Overall average of the repellency of sugar apple leave extract on Tribolium castaneum was 51.72 % and therefore Aqueous extract of sugar apple leaves belong to the repellency class III. The percentage of mortality was the highest (15%) after 96 h of treatment while the lowest after 24 h of treatment. The data pertaining in the experiment showed that higher the exposure time was higher the percent mortality. It was suggested that the extract showed effective repellency on strored grain pest red flour beetle and the results will be contributed to Integrated Pest Management programme and their structural elucidations are underway.
Keywords: Aqueous extract, sugar apple leaves, Tribolium castaneum, repellency class, mortality.
Insect pests on stored grains are a problem throughout the world. Because they reduce not only the quantity and quality of grains but also their products are unfit for human consumption. Their damage to stored grains and grain products may amount to 5–10% in the temperate zone and 20–30% in the tropical zone (Nakakita, 1998). Such damage may range up to 40%, in countries where modern storage technologies have not been introduced (Shaaya et al., 1997).
The effective controlling method of grain protection from insect infestation is the use of chemical agents since it is the simplest and cost-effective means of concerning stored product pests (Hidalgo et al., 1998). However, chemical insecticides have serious problems such as pest resurgence and resistance, lethal effects on non-target organisms including human, the risk of user’s contamination, food residues and environmental pollution (Tapondjou et al., 2002).
Tribolium castaneum is a major pest of stored grain products causing severe damage. This species is a long association with human stored food such as flour, cereals, pasta, biscuits, beans and nuts causing loss and damage (Pugazhvendan et al., 2009). Besides, this pest has developed resistance to many common pesticides, whose intensity differs in different regions.
In resolving these problems, biopesticides have gained huge importance in recent grain protection technology because of their insecticidal properties. Many plants have now been reported for their insecticidal properties. Among them, sugar apple leaves, seeds and barks are widely employ by small scale farmers to protect their crops and grains from infestations. They are traditionally and widely used against stored grain pests due to their easy accessibility and biodegradable nature (Anita et al., 2012). Moreover, there is a serious problem because most of people use unwisely chemical pesticides for stored grain pests and therefore these chemical residues may be persist in our food grains. Thus, there is an urgent need to develop safe alternatives to conventional insecticides and fumigants for the protection of grain products against insect infestations.
Therefore, in the present study, the repellency and insecticidal properties of sugar apple leave extract on the stored grain pests Tribolium castaneum was experimented under laboratory conditions. The results will provide data useful for the development of new repellants for stored-product pests. The aim of this study was to investigate the insecticidal activities of the leave extract of sugar apple against red flour beetle.
1.1 Statement of the problem
The statement of the problem is an alternative of chemical pesticide against the infestation of stored grain products.
The objectives of the study were:
a. to test the repellency of sugar apple extract on red flour beetle and
b. to observe the mortality of beetle under the laboratory condition.
2. REVIEW OF LITERATURE
Khalequzzaman and Shajia Sultana (2006) described the insecticidal activity of Annona squamosa L. seed extracts against the red flour beetle, Tribolium castaneum (herbst). Insecticidal activity of the seed extracts of custard apple, Annona squamosa L. in petroleum spirit, ethyl acetate, acetone and methanol against Raj, CR1, FSS II and CTC-12 strains of the red flour beetle, Tribolium castaneum.
According to Duke (2008), one of the Annona squamosa leaf contents, borneol, is the possibly effective as insecticides or repellent. Kesetyaningsih (2012) recorded that Annona squamosa leaves have not been much researched as insecticides and are still in discussion about the active compound of Annona squamosa by way of insecticide.
Anita et al. (2012) described the efficacy of pulverised leaves of Annona squamosa (L.), Moringa oleifera (Lam.) and Eucalyptus globulus (Labill.) against the stored grain pest, Tribolium castaneum (Herbst.) In the case of M.olifera, the minimum days required for 100% mortality with 2.0g concentration was 11, while with 0.05g it was 18 days.
Pugazhvendan et al. (2012) stated the insecticidal and repellant activities of plants oil against stored grain pest, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). They ecorded the five plants oil for their insecticidal and repellent activity against Tribolium castaneum (Herbst), a stored grain pest they were tested in the laboratory during the study period.
Isman and Seffrin (2014) stated that the crude extracts from seeds, leaves, bark, twigs, and fruits obtained from the plant species of Annonaceae have been extensively tested in recent years for bioactivity to pest insects and related arthropods worldwide.
Shahzad Saleem et al. (2014) also described the insecticidal activity of essential oils of four medicinal plants against different stored grain insect pests. To investigate the insecticidal activity of essential oils of four locally grown plants against three major insect pests, Tribolium castaneum, Trogoderma granarium and Cryptolests ferrugineus responsible for economic loss to stored commodities of 5, 10, 15 and 20µ 1/l water laboratory conditions at 30 2 and 65 5% relative humidity.
Thinzar Hlaing (2015) reported the efficacy of Annona squamosa L. 1753 leaf extract as pesticide for the control of Spodoptera litura, Spodoptera exigua and Phenococcus solenopsis were tested with spraying method of Annona squamosa leaves extract concentrations 0% (control), 60%, 75% and 90% respectively.
For the above considerations, the present study is aimed to use the botanical pesticide from the local plants as a substitute of synthetic pesticide in order to fulfill the local needs and a part of integrated pest management.
3. Materials and Methods
The experiment was carried out at the Department of Zoology, University of Magway during December 2018 to March 2019.
3.1 Test insects
In the present study, the adult specimens of species to be tested were reared with stored grains as they were collected, Tribolium castaneum in sesame container.
3.2 Preparation of aqueous extract of Annona squamosa leaf
Leaves were collected from the surrounding area of Magway University, dried in the shade and finely chopped. Then 50g of dried leaves powder was soaked in the one liter of pure water for 24h at room temperature to obtain 5 percent concentration (Cruz et al., 2004 cited by Paul et al., 2016).
3.3 Area preference and mortality test
Area preference tests were performed using the method of Tapondjou et al. (2005) with modifications. Working solution (one mL) of the aqueous extract of sugar apple leaves was uniformly applied to half a filter paper disk to single dose concentration of five percent. The same volume of the solute without extract (pure water) was applied to the other half to serve as a control. Paper disks were placed in 90-mm petri dishes and the solvent allowed drying. Half an hour after the application, ten adults of T. castaneum were placed in the center of each paper disk. The dishes were added with 50 g rice food supplied for insects and covered by plastic and maintained at room temperature. Insects were counted in treated and control areas at 24 hour (h), 48h, 72 h and 96 h after insect release. With ten insects per dish and four replicate dishes, a total of 40 insects were used. The experimental design was completely randomized, with four replicates. Insect mortality was evaluated after every 24 hours of exposure to impregnated filter paper (Moreira et al., 2007).
Percentage of mortality was calculated using Abbott’s formula by counting number of dead insects in each petridish 24 h, 48 h, 72 h, and 96 h after treatments. Adult insects were considered dead when no response was observed after probing them with fine brush. At the end of each assessment, dead insects were removed. The experiment was arranged in completely randomized design (CRD).
3.4 Data analysis
Average percentage repellency from four replicates was calculated for each time period (24 h, 48 h, 72 h and 96 h) in the experiment. Positive (+) values indicated repellency and negative (-) values showed the attractancy. The overall average values with respect to the exposed period were calculated and assigned a repellency class using the following scale described by Mc Govern et al., (1977). The percent repellency was calculated by following Liu et al., 2013
4.1 Repellent activities of A.squamosa leave extract on the adults of Tribolium castaneum
In adult bioassay, the repellency of aqueous extract of sugar apple leaves on Tribolium castaneum was tested for single dose of five percent concentration under laboratory condition. In the experiment, the calculated repellency are presented in Table 1. There was no relation in the percentage repellency as the time of treatment was increased (Fig. 1). In this case, the activity of 48.72 % when observed at the end of 24 h treatment, decreased to about 40.54% and 41.18 % respectively at the end of 48 h and 96 treatment. The extract of sugar apple leaves showed the highest level of repellant activity at the end of 72 h treatment. After 96 h of treatment, percentage of repellency was decreased about 41.18 %.
Based on the overall average percentage of repellency at 24 h, 48 h, 72 h and 96 h plants were categorized into different repellency classes (MC Govern et al., 1977), as mentioned in the methods section. The repellency classes are; class I, 0.1 to 20%; class II, 20.1 to 40 %; class III, 40.1 to 60%; class IV, 60.1 to 80%; and class V, 80.1 to 100% of repellency. Overall average of the repellency of sugar apple leave extract on Tribolium castaneum was 51.72 % and therefore Aqueous extract of sugar apple leaves belong to the repellency class III.