Natural products from Nepeta cataria L. and Origanum vulgare L. as tools for pest management
Creators: name: Patel, Harna K.
Publisher: name: No Publisher Supplied
Year: 2023

description: Despite the effectiveness of essential oils as antibacterial and insect repellent agents, there are many challenges associated with their application. Some of the challenges associated with the application of essential oils in the field for pest management are the lack of reliable sources of essential oil with consistent chemical profiles, high essential oil yield as well as reduced efficacy and longevity of essential oils due to their volatile nature. Furthermore, information regarding the applications of essential oils against certain bacterial pathogens of importance to agriculture and urban pests is scarce, presenting a gap in the knowledge regarding the potential application of essential oils as antibacterial and insect repellent agents. To address the availability of reliable high quality raw materials for essential oil production, two new high essential oil yielding oregano (Origanum vulgare L.) cultivars ‘Pierre’ and ‘Eli’ rich in the terpene carvacrol, with desirable agronomic traits suitable for growing in the Mid-Atlantic Region of the United States developed previously at Rutgers University, to support the flavors, fragrance, food, poultry, and other industries, were evaluated, and released for public and commercial use. Additionally, field studies were conducted to assess the performance of different genotypes and the previously developed and patented cultivars of catnip (Nepeta cataria L.) ‘CR3’ and ‘CR9’ rich in nepetalactone, to better understand the effect of genotype, harvest and their interaction on the biomass yield and contents of secondary metabolites of value. To address the gap in knowledge regarding the applications of catnip and oregano essential oils against some species of the bacterial pathogens of importance to agriculture in the genus Pseudomonas and Xanthomonas, which have a wide host range and affect economically valuable crops, the antibacterial activity of catnip and oregano essential oils to Pseudomonas syringae, Pseudomonas cichorii and Xanthomonas perforans was evaluated in vitro in a pilot study using the agar well diffusion assay. In this work, catnip displayed moderate antibacterial activity while oregano displayed strong antibacterial activity against these bacterial pathogens. In addition to assessing their antibacterial activity, the insect repellent activity of catnip and oregano essential oils was evaluated against the common bed bug (Cimex lectularius L.), an urban pest which is difficult to control. In preliminary studies, both essential oils displayed strong repellent activity against bed bugs. Thus, mixtures of catnip and/or oregano essential oils with other terpenes reported to have insect repellent activity were tested. After the mixtures showed strong repellency against bed bugs in primary assays, the repellency of select mixtures was further evaluated with a commercial repellent in the presence of a bed bug attractant. Furthermore, when the effect of storage (storage time and temperature) on the bioactivity of the promising repellent mixture was also tested, the mixture maintained strong repellency even after storage at higher than normal temperatures, indicating stable bioactivity. Altogether, catnip and oregano essential oils have strong bed bug repellent activity and can be considered for further evaluation and product development for pest management.