~ 449 ~ Journal of Entomology and Zoology Studies 2018; 6(6): 449-452 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2018; 6(6): 449-452 © 2018 JEZS Received: 17-09-2018 Accepted: 18-10-2018 Suchithra Kumari MH Assistant Professor, Department of Entomology, College of Horticulture, Mudigere, Karnataka, India Hanumantharaya L Professor and Head, Department of Entomology, College of Horticulture, Mudigere, Karnataka, India Thippeshappa GN Professor and Head, Department of Soil Science and Agricultural Chemistry, College of Agriculture, Shivamogga, Karnataka, India Yalleshkumar HS Assistant Professor, Department of Fruit Science, College of Horticulture, Mudigere, Karnataka, India Srinivas MP M. Sc. (Hort.), Department of Entomology, College of Horticulture, Mudigere, Chikkamagaluru dist. University of Agricultural and Horticultural Sciences, Shivamogga, Karnataka, India Correspondence Srinivas MP M. Sc. (Hort.), Department of Entomology, College of Horticulture, Mudigere, Chikkamagaluru dist. University of Agricultural and Horticultural Sciences, Shivamogga, Karnataka, India Bio-efficacy of insecticides against fruit fly, Bactrocera cucurbitae (Coquillett) in cucumber Srinivas MP, Suchithra Kumari MH, Hanumantharaya L, Thippeshappa GN and Yalleshkumar HS Abstract Field experiment on the effect of different insecticides against fruit fly, Bactrocera cucurbitae (Coquillett) infesting cucumber was carried out during kharif 2017 and summer 2018 at Chikkamagaluru. The results revealed that significantly lowest number of ovipositional punctures (0.72 and 0.98 /fruit), lowest number of maggots (8.0 and 8.93 /fruit), lowest percent fruit infestation (14.92 and 17.90 %), highest marketable fruit yield (15.63 and 16.49 t/ha.) and more cost-benefit ratio (1: 2.30 and 1: 2.43) was recorded in the treatment with spinosad 45 SC (0.15 ml/l) during both kharif and summer season, respectively and it was on par with the treatment dichlorvos 76 EC (1.0 ml/l). However, highest number of ovipositional punctures (2.72 and 3.01 /fruit), highest number of maggots (19.13 and 19.80 /fruit), highest percent of fruit infestation (46.91 and 56.79 %) and lowest marketable fruit yield (10.75 and 9.01 t/ha.) was obtained in the jaggery treatment (10 g/l) which was followed by control in both kharif and summer season, respectively. During the kharif season the lowest cost-benefit ratio (1: 1.62) was obtained in jaggery treatment while in summer season cyantraniliprole 10.26 OD recorded the lowest cost-benefit ratio (1: 1.34). Keywords: Cucumber, fruit fly, insecticides, kharif, management, summer 1. Introduction Cucumber (Cucumis sativus L.) the popular crop of the Cucurbitaceae family is grown throughout the world. The melon fruit fly, Bactrocera cucurbitae (Coquillett) is a serious pest of cultivated cucurbits. It was first reported in India by Lefroy during 1907 which reduce not only the quality of fruits and vegetables but also a serious limiting factor in the production of gourds, cucumber, melon and other cucurbits to the extent that it's growing may become highly unprofitable. Generally, the female fruit flies puncture the soft and tender fruits by their sharp ovipositor and lay the eggs under fruit tissues and guumy fluid oozes from the puncture. The fruit flies also oviposit in the tender plant tissues such as terminals, unopened flowers, young stems and seedlings which may result in the death of the plant (Kate et al., 2009) [1] . After hatching, the maggots feed on the pulp of the fruits by making galleries and simultaneously the secondary infection also arises, resulting in rotting of fruits (Gupta and Verma, 1995) [2] . The extent of losses caused by B. cucurbitae varies from 30 to 100 percent depending on the cucurbit species and season (Dhillon et al., 2005) [3] . The control measures are as difficult as in the Tephritidae family of insects. Some weak link in the life history of the pest is exploited by the economic entomologists. Several management techniques are being applied against this pest because three of its life stages are hidden and the only adult stage is the usual target for its management. Mostly chemically-based insecticides are used for their control without knowing the ill effects of these chemicals on the environment. The residues of pesticide affected the export potential of gourd because of serious concern of the importing countries (Quasem, 2003) [4] . Moreover, repeated use of toxic insecticides is not only hazardous to the environment but also directly affects the health of the farmers and consumers. Therefore, it is necessary to explore economically sustainable and environment-friendly insecticides for management of fruit fly. However, the information on the use of safer insecticides to manage this pest on cucumber is very scanty. Therefore, the present investigation was undertaken to evaluate the bio-efficacy of some insecticides against B. cucurbitae attacking cucumber under hill zone of Karnataka.