51 Bio physical mechanism of resisitance to major pests of brinjal S. LEELA PRAVEEN*, N. EMMANUEL 1 , C.P.VIJI 2 , K. UMAJyOTHI 3 and D.R. SALOMI SUNEETHA 4 College of Horticulture, Dr.Y.S.R. Horticultural University, V.R.Gudem-534101, Andhra Pradesh, India *Email:-praveen49.sigireddy@gmail.com ABSTRACT: An Experiment was carried out with 44 brinjal genotypes at college farm, College of Horticulture, Dr.Y.S.R. Horticultural University, V.R.Gudem to see the effect of biophysical characters of plants on the infestation of major pests on different brinjal genotypes. It was observed that among the characters infuencing Trichome density (-0.797 and -0.809), internodal length (-0.242 and -0.257), fruit length width ratio (-0.249 and -0.254) exhibited strong negative correlation with respect to Fruit and shoot damage. While shoot thickness (0.980 and 0.991) and diameter of fruit (0.426 and 0.445) showed signifcant positive correlation by fruit and shoot borer. Subsequently, Jassid intensity was showed signifcant positive correlation with shoot thickness (0.401), while negative correlation was observed with trichome density (-0.275) and fruit length width ratio (-0.232). Furthermore, whitefy and hadda beetle number showed negative correlation with shoot thickness (-0.474 and -0.517) and positive correlation with trichome density (0.323 and 0.436), internodal length (0.376 and 0.383). Keywords: Biophysical, resistance, brinjal and major pests INTRODUCTION Brinjal, also known as eggplant or aubergine (Solanum melongena L.) is an imperative vegetable crop grown in India and other parts of the world. Diminutive productivity of brinjal accountable by numerous factors, as it is subjected to insect pest are the main constraint in the successful cultivation of brinjal right from nursery stage till harvesting (Reghupathy et al., 1997). Moderate temperature and high humidity is positive discrimination to the population build-up of insect pests due to seasonal changes (Shukla et al., 2010 and Bhushan et al., 2011). Amongst the chemical control is most widely used and it become the chief source in farmers feld level for managing insect pests in brinjal it leads to insect pests developed resistance. Environmental contamination, bioaccumulation and bio magnifcation of toxic residues and commotion in ecological balance due to repeated use of broad spectrum synthetic chemicals. Hence, there is an imperative need to look for safer alternative pest management tactics. Use of resistant varieties is recognized as a signifcant tool in bio intensive pest management system. Attraction, feeding and oviposition of the insect pests coupled with morphological and physical characteristics of plants and fruits. Although host plant resistance alone or in amalgamation with other methods is environmentally safe and companionable with IPM, however this approach is realistic only when resistant varieties of crops subsist and recognized. Number of pesticide applications can be reduced even a moderate level of resistance (Srivastava and Butani 1998). However, a colossal scope exists in fnding resistant sources to major pests as a sizable share of 4,343 brinjal accessions (NBPGR-2015, New Delhi) conserved at the NBPGR still tranquil. In this background, the present investigation was carried out to screen 44 brinjal genotypes for their response to major pests and to expedite their morphological attributes of resistance to the pests. Keeping in view the economic importance of brinjal crop in daily use, where use of insecticides is not desirable, the present studies were undertaken to fnd out the source of resistance against the major insect pests of brinjal. MATERIALS AND METHODS A feld experiment was conducted in augumented randomized block design (RABD). The genotypes of 44 brinjal varieties screened against major pests. Four weeks old seedlings were transplanted with a spacing of 75 x 60 cm during September to March 2016 at College of Horticulture, Dr.Y.S.R.Horticultural University, V.R.Gudem. The cultural practices except plant protection measures were followed as per the crop production guide for horticultural crops. They were planted by maintaining ten plants per treatment/entry. Five plants per treatment were tagged at random and observed for the incidence of major pests in each brinjal genotype at weekly interval starting from transplanting to harvest (David, 2000). The pest population/ damage were recorded at weekly interval commencing from seventh day after transplanting (DAT). Pest Management in Horticultural Ecosystems Vol. 25, No.1 pp 51-62 (2019) ders)