Bioefficacy of Vitex Negundo Extract Profile on the Ovipositional Behaviour of Eupterote Mollifera
Total Page：16
File Type：pdf, Size：1020Kb
Journal of Interdisciplinary Cycle Research ISSN NO: 0022-1945 BIOEFFICACY OF VITEX NEGUNDO EXTRACT PROFILE ON THE OVIPOSITIONAL BEHAVIOUR OF EUPTEROTE MOLLIFERA V. Ramamurthy1, H.V. Anil Kumar2 and G.K.Ayyadurai3 1,P.G & Research Department of Biochemistry, Marudupandiyar College, Thanjavur, 613 403, Affiliated to Bharathidasan University, Tiruchirappalli, Tamil Nadu. 2Department of Environmental Science & Laboratory of Applied Biological Science, DVS College of Arts & Science, Shimoga-577 201, Karnataka, India. 3Department of Chemistry, Sri Sai Ram Engineering College, West Tambaram, Chennai – 600 044, Tamil Nadu. ABSTRACT The dangers of insecticides to human and to the environment have initiated biologists to choose other means of preventing insect infestation on crops by the use of botanical materials. This study was conducted to evaluate the efficacy of utilizing Vitex negundo leaf extract as an environment friendly pesticide. Effect of host plant, Ricinus communis (Castor) and the non-host plant, Vitex negundo on the egg laying behaviour of a leaf miner, Eupterote mollifera was investigated. The results of the experiments concluded that the Castor leaves (Ricinus communis) stimulated oviposition in all females of E.mollifera and the average fecundity was 122 eggs/female. The nochi plant leaf extract (Vitex negundo) inhibited oviposition not only in the absence of castor leaf stimuli but also in the presence of castor leaves. The average fecundity was decreased in females of E.mollifera when treated with nochi leaf extract. Keywords: Eupterote mollifera, Ricinus communis, Vitex negundo, Fecundity Oviposition. INTRODUCTION The plant kingdom is the most efficient producer of chemical compounds (primary and secondary metabolites) synthesizing many products having wide array of functions that are used in defense against insect pests. Phytochemicals with a considerable capacity to reduce adult emergence at low dosage, which reduce the recruitment over time is the desired characteristic of botanical (Balandrin et al., 1985). The adult emergence is affected by phytochemicals, which often cause acute and chronic toxicity. These compounds exhibit effects on developmental stages of exposed larvae, which can produce morphological abnormalities in different developmental stages such as lack of melanization in larval and pupal stages, dead larvae-pupal intermediate stage with the head of pupa and the abdomen of a larva, dead adults with folded wings in pupal exuvium and emerged adults unable to escape the pupal exoskeleton, half ecdysed adults etc (Facknath and Kawol, 1996). One of the important attributes of insects is their immense reproductive potential. Insect reproduction includes mating behaviour, oviposition behaviour, fecundity and fertility. Phytoconstituents present in many plants can easily challenge any of these aspects of insect reproduction (Schmit et al., 1991; Asawalam and Adesiyan, 2001). Many of the secondary metabolites present in plants adversely alter the fecundity and fertility of insect pests (Ramamurthy et al., 2012). It has various uses in folk medicine (Nammi et al., 2003). Potentials of phytochemicals present in the C. roseus as insecticide were widely studied against a variety of insects. Exposure to aqueous, ethyl acetate and methanol extracts of C. roseus have been reported to induce the larval and pupal mortality in Anopheles stephensi and Culex quinquefasciatus (Subarani et al., 2013). Volume XI, Issue IX, September/2019 Page No:660 Journal of Interdisciplinary Cycle Research ISSN NO: 0022-1945 Vitex negundo, commonly known as the Chinese chaste tree, five-leaved chaste tree, or horseshoe vitex, or nisinda is a large aromatic shrub with quadrangular, densely whitish, tomentose branchlets. It is widely used in folk medicine, particularly in South and Southeast Asia. Vitex negundo is an erect shrub or small tree growing from 2 to 8 m (6.6 to 26.2 ft) in height. The bark is reddish brown. Its leaves are digitate, with five lanceolate leaflets, sometimes three. Each leaflet is around 4 to 10 cm (1.6 to 3.9 in) in length, with the central leaflet being the largest and possessing a stalk. The leaf edges are toothed or serrated and the bottom surface is covered in hair. The numerous flowers are borne in panicles 10 to 20 cm (3.9 to 7.9 in) in length. Each is around 6 to 7 cm (2.4 to 2.8 in) long and is white to blue in color. The petals are of different lengths, with the middle lower lobe being the longest. Both the corolla and calyx are covered in dense hairs. The fruit is a succulent drupe, 4 mm (0.16 in) in diameter, rounded to egg-shaped. It is black or purple when ripe. Eupterote mollifera is a polyphagous pest often assuming serious proportion on it. It is a leaf feeder and infests on moringa, pomegranate, rose, cotton, mango and redgram. There is a paucity of information on the control of this pest by botanical insecticides. Therefore, the present investigation is undertaken to evaluate the bioefficacy of an insect resistant plant (Vitex negundo) leaves on the egg laying behavior of a leaf miner pest, Eupterote mollifera in castor agro ecosystem. MATERIALS AND METHODS Test insect culture: The leaf miner, Eupterote mollifera were collected from the castor infested fields in and around Pattukkottai, A colony consisting of both males as well as females was maintained in the laboratory conditions (Temp: 26 ± 20C; R.H: 65 ± 5%). Both the adults and different larval instars were kept separately in glass rectangular jars (30 x 18 x 8.5 cm), each covered with a muslin cloth at its top. The larvae were fed ad libitum with castor leaves bits while the adults with 10%. Honey solution mixed with castor leaf powder. Plant extracts preparation: Healthy leaves of the host plant, Castor (Ricinus communis) and non-host plant, Nochi (Vitex negundo) were collected in and around Pattukkottai. They were cleaned by simple washing with fresh tap water and homogenized in distilled water and centrifuged. The supernatants were filtered with Whatman Paper No. 1. The leaf extract was dried in a vacuum evaporator. Twenty gram of each plant extract was obtained, sealed with wax and kept in a dark chamber for further experimental studies. Mating studies: Both adult male and female of E.mollifera moths were sorted out from the stock culture, soon after their emergence and each pair of both sexes were allowed to remain in circular glass mating jars (100 ml cap.) to facilitate random mating for 1-2 days. Experimental Design: After mating studies, the following experiments were performed individually. Three groups of mated females were chosen from the mating jars for Experiment No. 1. Group I was treated with the Chromatograph paper impregnated with aqueous R.communis leaf extracts. Group II was treated with empty chromatograph paper and kept as control. Group III Volume XI, Issue IX, September/2019 Page No:661 Journal of Interdisciplinary Cycle Research ISSN NO: 0022-1945 was treated with chromatograph paper impregnated with V.negundo leaf extract. Two Groups of mated females were selected from the mating jars for Experiment No.2. Group I was treated with R.communis leaves only and kept as control. Group II was treated with V.negundo leaf extract. The data obtained on the observations on the egg laying behavior i.e. percentage of egg laying females for the eggs laid in different classes in both control and treated females in Experiments No. 1 and 2 were subjected to Statistical analyses (Bailey, 1964). RESULTS The host plant, Ricinus communis leaf extract stimulated oviposition in female moths of E.mollifera (Group I) and the maximum of percentage of egg laying females was recorded as 61 for the eggs greater than 100. The average fecundity for this group was 120 eggs/female. In the absence of castor leaf stimuli, 22% of the mated females of E.mollifera laid a maximum of 30 eggs while 20% of the mated females laid a maximum of 100 eggs and 13% of the mated females laid greater than 100 eggs. However, the average fecundity was only 30 eggs/female in this Group II. In Group III, about 86% of the mated females did not oviposit at all and only 13% laid a maximum of 30 eggs. The inhibitory action of nochi plant V.negundo leaf extract was well noticed in the eggs laying habit of E.mollifera (Table 1). About 22% of the mated female moths laid a maximum of 100 eggs while 72% of such females laid eggs greater than 100 while they were treated with fresh castor leaves (Group I). Egg lying was inhibited in 48% of mated females when they were allowed to oviposit on the castor leaves sprayed with nochi. (V.negundo) plant leaf extract (Group II). The average fecundity for Group I control mated females (n=30) was 142 eggs as against for treated female of the same sample size was 8.5 eggs. The insect resistant plant V.negundo leaf extract sprayed on the host plant, castor leaves masked the stimulatory action of the host plant and inhibited the egg laying behavior of E.mollifera (Table 2). DISCUSSION The discovery and understanding of mechanisms of host plant selection by phytophagous insects opened a wide array of potentialities for the development of eco – friendly crop protection methods. These include the use of resistant plant varieties and the application of various behavior modifying chemicals. The discussion of host plant selection strategy may result in a decline in ovipositional habit or may affect the development and longevity of the insect (Adeniyi et al. 2010). No amount of control measures will be successful unless resistant plant bio- compounds are so designed to attack the reproductive behavior of insect pests. In Experiment No. 1, the percentage of egg laying females treated with host plants, R.communis (Castor) was increased and therefore concluded that R.communis could be more effective in inducing oviposition in all females of Group I (Rajkumar and Jebanesan, 2002) while in absence of the host plant leaf stimuli, 22% of the females did not lay eggs; only 13% laid more than 100 eggs (Group II).