Influence of biophysical characteristics of brinjal varieties on the infestation of brinjal shoot and fruit borer, Leucinodes orbonalis Guenée

A study was conducted during summer 2014 (February – May, 2014) and Rabi, 2014 (September, 2014 - January, 2015) at Vegetable Research Station, Palur, Tamil Nadu, India to find the relationship between biophysical characteristics of brinjal genotypes and infestation of Leucinodes orbonalis by screening 35 germplasm of brinjal. Thirty five germplasm were planted in the field having three replications of 05 plants for each treatment. The biophysical characteristics of brinjal genotypes viz., shoot thickness at 2.5 cm below the tip, number of trichomes on under surface of leaves, length of pedicel, calyx and fruit, and diameter of fruit were measured to correlate them with level of infestation by L. orbonalis. At the time of harvesting the per cent infestation of fruit were calculated. The results revealed that the shoot infestation by L. orbonalis negatively, but not significantly correlated with number of trichomes on leaves (r = -0.52) and positively correlated with shoot thickness (r = 0.05). Fruit infestation was positively but not significantly correlated with length of pedicel (r = 0.03) and calyx (r = 0.24) whereas non-significant and negative correlation was recorded between fruit infestation and fruit characters viz., length of fruit (r = -0.25) and diameter of fruit (r = -0.04). The shape and colour of fruit had no significant influence on the level of infestation Journal of the University of Ruhuna 2015 3(1): 21-28