Abundance and diversity of arthropod pests in sesame crop field

Abstract: Sesame (Sesamum indicum L.) is susceptible to a wide range of arthropod pests that can significantly reduce yield and quality. This study aimed to assess the diversity, seasonal abundance, and pest status of arthropod pests in sesame fields during the Kharif-I season 2023 at Gazipur Agricultural University (GAU), Bangladesh. The experiment was conducted in a Randomized Complete Block Design with 18 plots (3 m × 2 m) with three replications. Pest populations were monitored at 15-day intervals from seedling to harvest. A total of 15 arthropod pest species were recorded, representing five orders: Hemiptera (6 species), Coleoptera (4), Lepidoptera (3), Diptera (1), and Trombidiformes (1). Major pests included flea beetle (80.0%), whitefly (36.9%), jassid (14.2%), bihar hairy caterpillar (30.9%), sphinx caterpillar (30.3%), and leaf webber/capsule borer (28.7%). Minor pests such as leaf miner, epilachna beetle, aphid, red pumpkin beetle, red spider mite, and weevils were also observed. Seasonal abundance peaked on 15 May, with total pest counts reaching 97.3 individuals per plot. Whitefly was the most abundant species (22.4%), followed by red pumpkin beetle (13.2%), jassid (13.1%), and bihar hairy caterpillar (9.8%). Pest richness was the highest at early crop establishment stage (20.1 species), declining to 6.3-6.0 species as the crop matured, while abundance remained steady (0.6 individuals per plant) and evenness was low (0.2), indicating dominance of a few key pests. These findings highlight the complex pest ecosystem in sesame fields, with early-season minor pests giving way to highly adaptable sucking and lepidopteran pests that dominate later in the season. 

Keywords: Arthropod, seasonal abundance, Sesamum indicum, pest diversity, species richness.