Beauty and the pest: ornamental plant biomass valorization for the management of lepidopteran crop and storage pests

Insects belonging to the order Lepidoptera comprise a large number of economically important pests in agricultural systems. Although their control still largely relies on the use of synthetic insecticides, increasing attention is being directed toward the development of alternative, nature-based solutions that are environmentally sound and sustainable. In this context, urban green spaces and managed landscapes constitute an underutilized reservoir of green waste that can serve as a raw material for the development of botanical insecticides. This review aimed to analyze recent studies investigating plant-derived materials obtained from ornamental species for the production of extracts and essential oils evaluated against lepidopteran pests. A systematic literature search was performed in the Web of Science database, targeting peer-reviewed original research articles published within the last ten years. According to the predefined selection criteria, a total of 72 plant species from 32 families were identified and included in the analysis. Approximately 80% of examined taxa exhibited insecticidal properties, while antifeedant activity was reported for extracts and essential oils derived from 54% of the species. The insect species tested for susceptibility to these plant-based preparations belonged to ten families, with the most frequently investigated pests including Plutella xylostella (Plutellidae), Spodoptera frugiperda (Noctuidae), Spodoptera litura (Noctuidae), and Lymantria dispar (Erebidae). Ornamental plant species included in this review represent a heterogeneous group of woody and herbaceous taxa that generate considerable amounts of biomass. However, variability in biomass quantity and quality, together with challenges related to its acquisition and management, represent key limitations in the conversion of green waste into value-added products. Once these challenges are effectively addressed, biomass valorization for biopesticide development has the potential to support the principles of a circular bioeconomy and contribute to broader sustainability goals.