EVALUATION OF SOYBEAN GENOTYPES FOR THEIR OVIPOSITIONAL PREFERENCE TO SPODOPTERA LITURA (FABRICIUS) Prashant K. Natikar* and R. A. Balikai Department of Agricultural Entomology, College of Agriculture, University of Agricultural Sciences, Dharwad - 580 005, India. *e mail: shanthunatikar@gmail.com (Accepted 11 June 2015) ABSTRACT : Ten elite soybean genotypes were evaluated for their ovipositional preference to Spodoptera litura (F.) under laboratory conditions during kharif 2014 at the Main Agricultural Research Station, University of Agricultural Sciences, Dharwad. The varieties viz., DSb 1, DSb 21 and KHSb 2 were not preferred by Spodoptera to lay eggs as evidenced by no egg masses on their leaves. Maximum number of egg masses per leaf was observed in the variety RKS 18 with 4.33 egg masses per leaf, which was highly preferred by S. litura for its oviposition followed by JS 335 (4.00 egg masses/leaf). These were followed by JS 9560 (3.00 egg masses/leaf), JS 9305 (2.00 egg masses/leaf) and MAUS 61 (2.00 egg masses/leaf) which were on par with each other. DSb 23-2 and MACS 1394 were next in the order of receiving significantly more number of egg masses (1.00 egg masses/leaf). Key words : Genotypes, ovipositional preference, Spodoptera litura. J. Exp. Zool. India Vol. 18, No. 2, pp. 911-913, 2015 ISSN 0972-0030 INTRODUCTION Soybean (Glycine max (L.) Merrill) is the premier pulse and oilseed crop in India. It provides the cheapest as well as the highest source of edible vegetable protein than any other pulse crop. The protein and edible oil content in soybean accounts to 40-43 and 20 per cent, respectively. Soybean protein is rich in amino acids like lysine, methionine and cystine. Soybean cake and meal are used as protein supplement for human food products and animal feeds. In addition, it contains good amount of minerals, salts and vitamins (Thiamine and Riboflavin). Soybean meal is used as protein supplement in human diet, cattle and poultry feed (Alexander, 1974). The tobacco caterpillar, S. litura is an economically important polyphagous pest in India and considered as one of the major threats to the present-day intensive agriculture and changing cropping patterns worldwide, next only to Helicoverpa armigera (Hubner). Spodoptera litura is reported to feed on 150 species of plants (Rao et al, 1993) causing 26-100 per cent yield loss under field conditions (Dhir et al, 1992). For the management of S. litura in soybean, growers have been depending exclusively on application of various insecticides. As a result, many field populations of S. litura pests have developed multiple resistances and field control failure is often more frequent (Kranthi et al, 2002). Indiscriminate use of insecticides, multiple generations of insects per annum, year-round availability of host crops contributed to the insecticide resistance. The luxuriant crop growth, soft and succulent foliage of soybean attracts many insects and provides unlimited source of food, space and shelter. About 380 species of insects have been reported on soybean crop from many parts of the world. During the introduction of soybean in India in the early seventies, only about a dozen minor insect pests were recorded, while in 1997 this number has swelled to an alarming figure 270, besides 1 mite, 2 millipedes, 10 vertebrates and 1 snail (Singh, 1999). About 65 insect species have been reported to attack soybean from cotyledon to harvesting stage from Karnataka (Rai et al, 1973; Adimani, 1976; Thippaiah, 1997). Among these, defoliators such as S. litura, Thysanoplusia orichalcea (Fab), Spilarctia obliqua (Walk)] and H. armigera are feeding on foliage, flower and pods causing significant yield loss (Singh and Singh, 1990). Our realistic approach for controlling this pest is to grow genotypes resistant to S. litura. This reduces the need for insecticidal usage, thus preventing environmental pollution and the development of insecticide resistant pest strains and threat to natural enemies. Hence, keeping in view these points the present study was under taken. MATERIALS AND METHODS The S. litura culture was maintained in the laboratory by collecting the egg masses from field and the emerging larvae were fed with the castor leaves until pupation. The pupae were collected and kept in an emergence cage (40 x 40 x 40 cm) by providing 10 per cent honey solution as adult food. Four to five fresh castor leaves with petiole dipped in water were provided to facilitate the oviposition.