Studies were conducted at farmer’s field, Marhun, Bara (Hamirpur) in Himachal Pradesh to evaluate the potential of biochemical basis of host plant resistance in the management of melon fruit flies of cucumber (Cucumis sativus L.). None of the improved varieties tested showed significant and consistent resistance to this devastating pest. The genotype IC-430026 however, supported relatively less maggot population and thus suffered significantly lower damage (infested fruits) under no insecticide protection than the improved varieties. The different levels of biochemical constituents namely total sugars, total free amino acids and total phenols were observed in genotypes and improved varieties. The higher levels of total sugars and total free amino acids were observed in improved varieties KCU-006 and Mohani-5300. There was a clear significantly positive correlation between total sugars and melon fruit flies incidence.

Cucurbits, host plant resistance, Bactrocera spp., antibiosis, cucurbits

It is concluded that the genotype, IC-430026 seems to hold some promise and thus deserve closer study to establish more accurately the levels and mechanisms of resistance. This cucumber genotype would provide the much needed base for breeding varieties resistant to melon fruit flies. There is also the need to explore more germplasm and materials from various sources to identify those that are less susceptible to this key pest. Though difficult to find, insect pest resistant varieties should form the basis for developing sustainable IPM systems for cucumber. Breeding for resistance is a powerful tool in pest management and once it is achieved, it will not only reduce the cost of production but also substantially prevents the environmental pollution.

Sheikh Khursheed, Desh Raj, Z. A Bhat, Hamidullah Itoo and G.H. Rather (2023). Biochemical Basis of Bactrocera spp. (Diptera: Tephritidae) Resistance in some Genotypes and Improved Varieties of Cucumis sativus L. Biological Forum – An International Journal, 15(9): 792-997.