Biophysical, biochemical screening of guava varieties against fruitfly, (Bactrocera dorsalis) in guava

Abstract

The present investigation evaluated the biophysical and biochemical traits of five guava (Psidium guajava L.) varieties Taiwan pink, Taiwan white, Allahabad Safeda, Lucknow-49 and Lalithin relation to fruit fly (Bactrocera dorsalis Hendel) infestation under field conditions. Among the varieties Taiwan pink was most susceptible variety, recording the highest number of maggots per infested fruit (32.25) and 100 per cent fruit infestation, followed by Taiwan white. In contrast, Lalith exhibited the least susceptibility with significantly lower maggot population (10.73) and fruit infestation (18.47%). Biophysical traits such as Rind thickness, fruit firmness and number of seeds per fruit were significantly and negatively correlated with infestation. Biochemical analysis revealed that total sugars, reducing sugars, non-reducing sugars, moisture content and total soluble solids were positively correlated with fruit fly infestation, whereas pectin content, total phenols, titratable acidity and vitamin C exhibited significant negative correlations. Higher sugar and moisture levels in Taiwan pink and Taiwan white rendered these varieties more susceptible, while elevated phenols, pectin, acidity and vitamin C in Lalith contributed to resistance.