The advent of the “Green Revolution” was a great success in significantly increasing crop productivity. However, it involved high ecological costs in terms of excessive use of synthetic agrochemicals, raising concerns about agricultural sustainability. Indiscriminate use of synthetic pesticides resulted in environmental degradation, the development of pest resistance, and possible dangers to a variety of nontarget species (including plants, animals, and humans). Thus, a sustainable approach necessitates the exploration of viable ecofriendly alternatives. Plant-based biopesticides are attracting considerable attention in this context due to their target specificity, ecofriendliness, biodegradability, and safety for humans and other life forms. Among all the relevant biopesticides, plant essential oils (PEOs) or their active components are being widely explored against weeds, pests, and microorganisms. This review aims to collate the information related to the expansion and advancement in research and technology on the applications of PEOs as biopesticides. An insight into the mechanism of action of PEO-based bioherbicides, bioinsecticides, and biofungicides is also provided. With the aid of bibliometric analysis, it was found that ~75% of the documents on PEOs having biopesticidal potential were published in the last five years, with an annual growth rate of 20.51% and a citation per document of 20.91. Research on the biopesticidal properties of PEOs is receiving adequate attention from European (Italy and Spain), Asian (China, India, Iran, and Saudi Arabia), and American (Argentina, Brazil, and the United States of America) nations. Despite the increasing biopesticidal applications of PEOs and their widespread acceptance by governments, they face many challenges due to their inherent nature (lipophilicity and high volatility), production costs, and manufacturing constraints. To overcome these limitations, the incorporation of emerging innovations like the nanoencapsulation of PEOs, bioinformatics, and RNA-Seq in biopesticide development has been proposed. With these novel technological interventions, PEO-based biopesticides have the potential to be used for sustainable pest management in the future.

Cancer retains a central place in fatality rates among the wide variety of diseases known world over, and the conventional synthetic medicaments, albeit used until now, produce numerous side effects. As a result, newer, better, and safer alternatives such as natural plant products, are gravely required. Essential oils (EOs) offer a plethora of bioactivities including antibacterial, antiviral, antioxidant, and anticancer properties, therefore, the use of EOs in combination with synthetic drugs or aromatherapy continues to be popular in many settings. In view of the paramount importance of EOs and their potential bioactivities, this review summarizes the current knowledge on the interconnection between EOs and cancer treatment. In particular, the current review presents an updated summary of the chemical composition of EOs, their current applications in cancer treatments based on clinical studies, and the mechanism of action against the cancer cell lines. Similarly, an overview of using EOs in aromatherapy and enhancing immunity during cancer treatment is provided. Further, this review focuses on the recent technological advancements such as the loading of EOs using protein microspheres, ligands, or nanoemulsions/nanoencapsulation, which offer multiple benefits in cancer treatment via site-specific and target-oriented delivery of drugs. The continuing clinical studies of EOs implicate that their pharmacological applications are a rewarding research area.