Encouraging farmers to adopt biopesticides is a crucial strategy for protecting the ecological environment and achieving sustainable agricultural development. This study utilizes data from a micro-survey of 454 banana farmers from Hainan Province of China and employs a logit model to analyze the effects of aging, land fragmentation, and their interactions on farmers' adoption of biopesticides, as well as the heterogeneity of farmers in different household life cycles. The findings reveal that aging and land fragmentation both hinder biopesticide adoption, with farmers experiencing higher levels of aging and more fragmented land holdings being less likely to utilize biopesticides in banana production. Mechanism analysis uncovers an interaction effect between aging and land fragmentation that hampers biopesticide adoption. Furthermore, the effects of aging, land fragmentation, and their interaction on biopesticide adoption behavior vary across farmers in different family life cycles. Specifically, aging negatively affects biopesticide adoption behavior for farmers in support households, while land fragmentation negatively influences farmers in dependency and burden households. The interaction between aging and land fragmentation adversely affects farmers in burden households. Our findings highlight the importance of aging agricultural labor and land fragmentation to promote green agriculture in China and call for more relevant policies to encourage farmers with different household life cycles to adopt biopesticides in farming practices.