Taxonomy and Ecology of Ichneumonidae (Hymenoptera) Parasitizing Stem Borer Larvae in Sugarcane Plantations

Abstract

Taxonomy and ecology of Ichneumonidae (Hymenoptera) parasitizing stem borer larvae in sugarcane plantations were investigated to document species diversity, host associations, and ecological role in natural pest suppression. Field surveys were conducted in major sugarcane-growing regions, and parasitized stem borer larvae were collected from infested canes showing typical symptoms such as dead hearts, tunneling, and reduced tillering. Emerged parasitoids were preserved and identified using morphological taxonomic keys based on diagnostic characters including wing venation, metasomal structure, antennal segmentation, and ovipositor morphology. The study recorded multiple ichneumonid species associated with key stem borer pests, indicating a diverse parasitoid complex in sugarcane ecosystems. Ecological observations revealed that parasitoid abundance varied with crop stage, pest density, and agroclimatic conditions. Higher parasitism rates were observed during peak stem borer infestation periods, particularly in fields with reduced insecticide application and greater habitat heterogeneity. Ichneumonid activity contributed significantly to natural regulation of stem borer populations through larval parasitism, thereby reducing pest damage and improving crop health. Spatial distribution patterns indicated higher parasitoid presence in fields with mixed vegetation and nearby refugia, supporting their role as habitat-sensitive biological control agents. The study highlights the importance of ichneumonid parasitoids in the ecological management of sugarcane stem borers. These findings support conservation biological control strategies that enhance parasitoid populations through habitat management and reduced pesticide dependence in sugarcane agroecosystems.