Efficacy of Insecticides against Red Pumpkin Beetle (Aulacophora foveicollis) in Summer Squash at Gauradaha, Jhapa, Nepal

Abstract

Red Pumpkin Beetle (RPB), (Aulacophora foveicollis), is a major destructive insect pest of summer squash, leading to severe vigor and yield loss. A field experiment was conducted in Gauradaha Agriculture Campus in 2024 to assess the comparative efficacy of various chemical insecticides for the management of RPB in Summer Squash The experiment was conducted on a Randomized Complete Block design (RCBD) with 3 replications and 7 treatments. The treatments subjected to the crop were Azadirachtin 300 ppm (3ml/L), Spinosad 45% SC (0.4 ml/L), Cypermethrin 10% EC (1.5 ml/L), Beauveria bassiana 1.15% WP (3 g/L), Malathion 50% EC (2 ml/L), Chlorantraniliprole 18.5% w/w (0.4 ml/L), and water (1.2 L/plot) as a control. The results showed significant differences among treatments in reducing RPB population after each spray (P<0.05). The cypermethrin led to lower RPB population with an average of 1.59, 1.59, and 1.44 after the first, second, and third spray, respectively. The highest Population Reduction Over Control (PROC) was also observed with cypermethrin in both the second and third spray applications, at 23.07% and 14.54%, respectively. Beauveria bassiana was the second most effective treatment in controlling the population of PROC of 12.55, 16.32, and 8.72 after the first, second, and third spray, respectively, along with the lowest average RPB count at first (1.51) and second spray (1.57). Spinosad followed them with PROC value 22.98%, 8.72%, 10.22% and average RPB count of 1.64, 1.66, and 1.62, respectively. Findings suggested a significant impact of insecticidal treatments on crop yield, where the highest yield was observed in Cypermethrin-treated plots (28.21 Mt/ha), followed by Spinosad (26.06 Mt/ha) and Beauveria bassiana (20.36 Mt/ha). The lowest yield was recorded in the untreated control (11.66 Mt/ha). Overall, the study suggests the use of cypermethrin, Spinosad, and Beauveria bassiana for managing RPB in Summer squash in the local context of Gauradaha.