First Report of Native Grasshopper, <i>Gesonula mundata zonocera</i> (Navás, 1904) on Water Hyacinth (<i>Eichhornia Crassipes</i>) in the Philippines: A Novel Insect-plant Interaction with Biocontrol Potential

Eichhornia crassipes (Mart.) Solms, commonly known as Water Hyacinth, is a globally invasive aquatic plant with substantial ecological impacts. Arthropod-based biological control research in the Philippines has been limited, with efforts primarily focused on pathogenic fungi. This study investigated the arthropod fauna associated with E. crassipes in Davao del Norte, Philippines. The occurrence of Gesonula mundata zonocera (Navás, 1904) on E. crassipes was confirmed through field surveys and genitalia dissections, with subsequent validation via rearing and detailed taxonomic identification. Direct recovery of egg clusters from petioles in the wild, coupled with literature indicating petiole boring for oviposition, substantiates its reproductive association with the plant. Observed herbivory by G. mundata zonocera included: leaf feeding and petiole boring, potentially compromising plant structure. Statistical analyses indicated the highest E. crassipes infestation in nutrient-rich areas, with environmental factors significantly influencing both plant proliferation and herbivore activity. The identification of G. mundata zonocera as a naturally occurring herbivore of E. crassipes in the Philippines offers a promising avenue for integrated biological control, particularly in regions where established agents like Neochetina spp. are absent. This finding provides crucial baseline data for future research into the biocontrol potential of G. mundata zonocera and contributes to the development of sustainable, integrated pest management strategies for aquatic ecosystems in the Philippines and other tropical regions.