A formulation to encapsulate nootkatone for tick control.

Area of Science:

• Entomology
• Plant Science
• Materials Science

Background:

• Nootkatone, derived from grapefruit oil, shows promise for tick control.
• However, its application is limited by plant phytotoxicity and high volatility.
• Existing emulsifiable formulations lack residual activity and cause plant damage.

Purpose of the Study:

• To develop and evaluate a lignin-encapsulated nootkatone formulation.
• To compare its efficacy, phytotoxicity, and volatility against a standard emulsifiable formulation.
• To assess its impact on Ixodes scapularis tick control.

Main Methods:

• Volatility was measured by vapor trapping and simulated sunlight exposure.
• Plant phytotoxicity was assessed on cabbage (Brassica oleracea L.) and oat (Avena sativa L.) leaves.
• Toxicity against unfed Ixodes scapularis nymphs was determined using a treated vial technique.

Main Results:

• Encapsulated nootkatone exhibited significantly lower volatility (15% vs. 40% trapped) and higher residue after light exposure (92% vs. 26%).
• The encapsulated formulation caused less necrosis and retained greater leaf weight in treated plants.
• Encapsulated nootkatone demonstrated enhanced toxicity to I. scapularis nymphs (LC50 = 20 ng/cm2) compared to the emulsifiable form (LC50 = 35 ng/cm2).

Conclusions:

• Lignin encapsulation effectively reduces nootkatone volatility and plant phytotoxicity.
• The encapsulated formulation offers improved efficacy and residual activity for tick control.
• This approach presents a more sustainable and effective solution for managing tick populations.