Development and characterization of nanoemulsions loaded with essential oil and β-cypermethrin and their bioefficacy on insect pest of economic and medical importance

Development of bio-nano-herbicide using Eucalyptus citriodora essential oil against a notorious weed Echinochloa crus-galli

BACKGROUND

Weeds are a menace in agriculture causing crop yield reductions to the tune of 40-50%. To overcome the problems of weeds, herbicides have been used excessively to the extent that they have caused resistance in weeds, in addition to the environmental hazards. Nano-herbicides are intended to exploit botanicals to develop novel bio-nano-herbicide formulations. Bio-nano herbicide was developed using Eucalyptus citriodora essential oil combined high-energy approaches such as ultra-sonication and high-pressure homogenization. The formulation has hydrodynamic and physical sizes of 95.5 and 32.3-57.7 nm, respectively. The product was tested for their pre-emergence and post-emergence herbicidal activity against Echinochloa crus-galli.

RESULTS

Increased concentration of bio-nano-herbicide inhibited the pre-emergence of weed seeds. Treated weed seeds registered lower dehydrogenase (0.80 to 0.32), alpha-amylase (1.349 to 0.101 mg maltose), catalase (3.87 to 3.52 μmol H₂O₂ min-1 g-1 protein), peroxidase (3.96 to 3.61 U mg-1 protein min-1) and super oxide dismutase (0.94 to 0.56 U mg-1 protein min-1) activities than control. Further, foliar spray of 1% nanoemulsion recorded significantly lower total chlorophyll content (1.62 mg g-1 fresh weight), than the crude oil (2.58 mg g-1). The antioxidant enzyme activities increased immediately after the first spray and the weeds wilted after the second spray.

CONCLUSION

This study is a maiden attempt to clearly demonstrate that bio-nano-herbicide can be developed using Eucalyptus citriodora essential oil which has both pre-emergence and post-emergence inhibitory activities against the notorious weed Echinochloa crus-galli. Field studies are to be taken up in the near future to validate the herbicidal efficacy of the novel nano herbicide formulation. © 2025 Society of Chemical Industry.

Abd-Elrhmman M, M. E. A. Said Z, A. El-Sayed A, Ali AAI, Alkeridis LA, Al-Shuraym LA, Wang J, Zhang Q, Aioub AAA. Exploring the Potential Effectiveness of Croton tiglium Oil and Its Nano-Emulsion on Earias insulana (Lepidoptera: Nolidae)

Earias insulana Boisd. (Lepidoptera: Nolidae) is a major pest of cotton and other crops in Egypt, and the widespread use of insecticides has led to resistance. This study evaluates, for the first time, the bioactivity of Croton tiglium (Malpighiales: Euphorbiaceae) oil and its nano-emulsion (CTNE) against 25 newly hatched larvae of E. insulana Boisd. We assessed their biological effects across different developmental stages and performed histological and ultrastructural examinations. Gas-liquid chromatography (GLC) identified several bioactive compounds in C. tiglium oil crushed dry seeds, including fatty acids, hydrocarbons, and sterols. CTNE showed excellent quality with a zeta potential of -17.7 mV, an average particle size of 54.28 nm, and spherical droplets of 42.42 nm in diameter. The LC50 values for C. tiglium oil and CTNE were 9.02% and 2.70%, respectively. Both treatments significantly impacted the biological characteristics of E. insulana Boisd., including reduced larval and pupal weight, lower adult emergence, decreased fecundity, and increased mortality. Histologically, there was epithelial cell hypotrophy and detachment, while ultrastructural damage included chromatin condensation, nuclear envelope folding, and mitochondrial damage, indicating apoptotic degeneration. These findings suggest C. tiglium oil and CTNE as potential, safe alternatives to chemical insecticides.

Nano-Agrochemicals as Substitutes for Pesticides: Prospects and Risks

This review delves into the mesmerizing technology of nano-agrochemicals, specifically pesticides and herbicides, and their potential to aid in the achievement of UN SDG 17, which aims to reduce hunger and poverty globally. The global market for conventional pesticides and herbicides is expected to reach USD 82.9 billion by 2027, growing 2.7% annually, with North America, Europe, and the Asia-Pacific region being the biggest markets. However, the extensive use of chemical pesticides has proven adverse effects on human health as well as the ecosystem. Therefore, the efficacy, mechanisms, and environmental impacts of conventional pesticides require sustainable alternatives for effective pest management. Undoubtedly, nano-agrochemicals have the potential to completely transform agriculture by increasing crop yields with reduced environmental contamination. The present review discusses the effectiveness and environmental impact of nanopesticides as promising strategies for sustainable agriculture. It provides a concise overview of green nano-agrochemical synthesis and agricultural applications, and the efficacy of nano-agrochemicals against pests including insects and weeds. Nano-agrochemical pesticides are investigated due to their unique size and exceptional performance advantages over conventional ones. Here, we have focused on the environmental risks and current state of nano-agrochemicals, emphasizing the need for further investigations. The review also draws the attention of agriculturists and stakeholders to the current trends of nanomaterial use in agriculture especially for reducing plant diseases and pests. A discussion of the pros and cons of nano-agrochemicals is paramount for their application in sustainable agriculture.