Influence of Biochemical Traits on Resistance in Bitter Gourd Against Melon Fruit Fly Zeugodacus Cucurbitae (Coquillett)

Bitter gourd is an important vegetable and it is attacked by a number of insect pests viz., aphids, melon fruit fly, hadda beetle, pumpkin caterpillar and gall fly. Of these, melon fruit fly Zeugodacus cucurbitae (Coquillett) is the most important. Field experiments during 2018–19 in farmer’s field at Ellamanam village and laboratory studies at the Department of Plant Protection, Anbil Dharmalingam Agricultural College and Research Institute, Tamil Nadu Agricultural University, Tiruchirappalli District were conducted. A preliminary screening was carried out with 50 bitter gourd accessions (wild types and commercial cultivars). Among these, 12 accessions (2 resistant, 6 moderately resistant, 3 susceptible and 1 highly susceptible) were selected to study the influence of biochemical traits on larval density and reaction to adult fly. It was observed that moisture and protein content and chlorophyll pigments were significantly positively correlated with fruit damage. The total sugars, reducing sugar, phenol, ascorbic acid, peroxidase and polyphenol oxidase were significantly negatively correlated. Among the twleve accessions/ variety/ local types screened, some were resistant (TCR 393, Musiri local-1), few moderately resistant (MC-10, Ucha small, Bikaner-2, PKM local and CO-1), few were susceptible (MC-105, paravai local) and one was highly susceptible (MC-41).