EFFICACY OF VARIOUS INSECTICIDES AGAINST MAJOR INSECT PESTS OF SUMMER SQUASH (Cucurbita pepo) IN DHADING DISTRICT, NEPAL
Journal: Science Heritage Journal | Galeri Warisan Sains (GWS)
Author: Sapana Parajuli, Bhimsen Shrestha, Puspa Raj Dulal, Bina Sapkota, Samikshya Gautam and Srijana Pandey
This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Red pumpkin beetle, fruit fly, flea beetle, whitefly, squash bug, melon aphid, etc. are the major insect pests of summer squash resulting in a huge loss in quality and quantity to farmers A field trial was conducted to find out the comparative efficacy of various insecticides against the major insect pests of summer squash from January to June 2020 in Dhading district, Nepal. The experiment was laid in Randomized Complete Block Design (RCBD) with four different insecticides i.e. Imidachloropid 17.8 SL @1.5ml/l, Spinosad 45SC @1ml/L, Azadiractin (Nimbecidine) 500ppm @ 5 ml/L, Jholmol @ 1:5 concentrations, and normal water spray as control as five treatments. The treatments were replicated four times and ‘Anna 303’ variety of summer squash was used under study. The results revealed that, among all the insecticides evaluated at all the four sprays, Imidachloropid recorded the maximum reduction in the population of red pumpkin beetle (RPB) (about 90%), other insects (about 88%) and also showed minimum leaf infestation % (28.5%), and leaf damage % per plant (15.63%) and Spinosad being at par with Imidachloropid followed by Azadirachtin and Jholmol respectively. Imidachloropid and Spinosad also showed comparatively lower fruit infestation by fruit fly i.e. 18.5% and 20.5 % respectively than other insecticides. Both Imidachloropid and Spinosad treated plots were statistically (p<0.05) similar and significantly superior over other treatments for yield (52.11 and 50.31Mt ha-1 respectively), for fruit length (37.62 and 37.12cm respectively) and fruit diameter (26.78 and 26.51cm respectively). A negative and strong correlation was found between yield and mean population of RPB and other insects, leaf infestation % per plant, leaf damage % per plant, and fruit infestation % per plant whereas fruit length and diameter showed a positive correlation with yield. The benefit-cost ratio was highest for plot treated with Imidachloropid (4.21) followed by Spinosad, Azadiractin, Jholmol, and Control. Thus, Imidachloropid was the most effective and economic in controlling the major insect pests of summer squash.