Reproductive Biology of Billy Goat (Ageratum conyzoides L.) In Surigao, Philippines

Abstract Ageratum conyzoides L. (billy goat weed) is a widespread invasive species whose rapid spread is attributed to its prolific reproductive capacity. This study was conducted in agroforestry farms in Upper Libas, Tagana-an, Surigao del Norte, Philippines, to quantify seed production and germination performance of the species. Mature fruiting plants were collected following standardized seed biology protocols, and seed productivity was estimated using established reproductive structure–based formulas. Germination trials were conducted using 100 seeds distributed across five replicates under sunlight-exposed conditions, with moisture maintained throughout the seven-day period. Results revealed that A. conyzoides produces more than 35,000 seeds per plant, consistent with global reports of exceptionally high fecundity. Germination reached 100% within seven days, confirming the species’ strong capacity for rapid establishment under favorable light and moisture conditions. These reproductive traits, combined with its allelopathic potential, extended flowering period, and absence of natural enemies, contribute to its aggressive invasiveness and significant ecological impacts across forest, grassland, and agricultural ecosystems. The findings highlight the urgent need for integrated management strategies to mitigate the species’ spread, reduce its ecological and economic impacts, and protect biodiversity within agroforestry landscapes.