PHYSICO-MORPHIC VARIATIONS AMONG BRINJAL CULTIVARS AGAINST LEUCINODES ORBONALIS GUENEE (PYRALIDAE: LEPIDOPTERA) AND ITS MANAGEMENT WITH DIFFERENT TECHNIQUES

Abstract

Brinjal shoot and fruit borer (Leucinodes orbonalis Guenee) is a serious pest of brinjal and is responsible for colossal yield losses. The pest is mainly controlled by chemical insecticides which poses serious threats to human and environment thus demands the use of alternatives. The present studies were conducted with the objective to manage the pest with various methods other than use of chemical pesticides. Use of resistant cultivars is an economical and environmentally safer methods in pest management. In this regard thirteen brinjal cultivars were tested for their resistance against the pest on the basis of fruit infestation. The cultivars Nirala and Anmol were found relatively resistant, Karishma, Kanha (091) and Ep-273 were intermediate resistant and Naeelam and Black long were categorized as susceptible. In another experiment, relationship between various physico-morphic characteristics of brinjal cultivars and pest infestation was studied. The results showed variable infestation levels of L. orbonalis on different cultivars. Cultivar Naeelam showed maximum fruit infestation (58.60 and 48.09%) followed by Black long (47.93 and 33.31%), while minimum was observed in Nirala with (24.75 and 21.57%) fruit infestation during 2007-08 and 2008-09, respectively. Similarly, shoot infestation was found maximum in Naeelam (43.15 and 33.75%) followed by Kanha-091 (37.72 and 28.73%) and Nirala was found as least attacked by the pest showing 19.27 and 15.81% shoot infestation during 2007-08 and 2008-09, respectively. The correlation of different morphological plant characters with fruit infestation indicated very strong but negative correlation between fruit infestation and leaf trichomes, stem thickness and stem hair density. A negatively significant correlation was found between fruit infestation and plant height (r = -0.716), crown hair density (r = -0.672) while the correlations with leaf hair density (r = -0.623), and leaf area (r = -0.613), was also significant but negative. There was positive correlation of fruit infestation with yield (q/acre) and positive and non-significant correlation with number of primary branches/plant with r –value 0.661 and 0.319, respectively. Additionally, various management techniques were tested individually and in different combinations for the management of L. orbonalis. The integration of Trichogrammachilonis, hoeing and clipping of infested plant parts reduced fruit infestation to the maximum level (5.61, 6.14 and 6.66%) and maximum increase in yield (q/acre) (42.58, 35.99 and 39.29) at research farm PMAS Arid Agriculture University Rawalpindi, vegetable research farm NARC, Islamabad and Usman Khattar Vegetable Farm Taxila, Rawalpindi, respectively against L. orbonalis fruit infestation. Conclusively, the resistant cultivar “Nirala” and integration of different non chemical techniques (Trichogramma chilonis + hoeing + clipping) were recommended for the management of L. orbonalis in brinjal fields.