From plants to pest targets: Revisiting botanical insecticides for lepidopteran pest management

Abstract

Botanical insecticides, derived from plant sources, have been used for millennia, long before the advent of synthetic chemicals. Though marginalized since the Green Revolution, growing concerns about the environmental and health impacts of synthetic insecticides have revived interest in these natural alternatives. Lepidopteran pests, particularly caterpillars, remain among the most damaging agricultural threats and are still predominantly managed with synthetic insecticides. Botanical insecticides offer a promising alternative due to their biodegradability, reduced environmental persistence, and diverse bioactivities—including insecticidal, antifeedant, and repellent effects—linked to compounds from neem, jatropha, rotenone-containing plants, and other sources. Recent breakthroughs in nanoformulations, such as nanoemulsions and metallic or polymeric nanoparticles, have significantly enhanced the efficacy, delivery efficiency, and stability of botanical insecticides. Nano-encapsulated extracts—like neem or rosemary extracts combined with silver nanoparticles—have shown superior pest control at lower dosages and reduced phytotoxicity. Yet, these technological advances have outpaced our understanding of their ecological implications. Key knowledge gaps remain regarding long-term environmental impacts, resistance evolution in target pests, and non-target organism effects. Most research continues to focus on a narrow range of plant species and active ingredients, while broader issues like large-scale production, and field-scale efficacy are underexplored. To fully exploit the potential of botanical insecticides, future efforts must prioritize ecological risk assessment, broaden the spectrum of studied plants, and integrate molecular tools such as CRISPR-Cas9, RNA interference (RNAi), transcriptomics, and machine learning. These tools provide deeper insights into pest physiology and resistance mechanisms, promoting precision, resilience, and environmental safety. Realizing this vision will require interdisciplinary collaboration to develop greener extraction methods, establish harmonized regulatory pathways, and conduct rigorous ecological risk assessments.