Evaluation of a lignin-encapsulated nootkatone formulation against Tetranychus urticae (Acari: Tetranychidae)

Authors: ADDESSO, K - Tennessee State University; O'NEAL, P - Tennessee State University; LEAHY, S - Tennessee State University; TROSTEL, K - Tennessee State University; Behle, Robert

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/2018
Publication Date: 9/1/2018
Citation: Addesso, K.M., O'Neal, P.A., Leahy, S., Trostel, K., Behle, R.W. 2018. Evaluation of a lignin-encapsulated nootkatone formulation against Tetranychus urticae (Acari: Tetranychidae). Florida Entomologist. 101(3):435-440. https://doi.org/10.1653/024.101.0321.
DOI: https://doi.org/10.1653/024.101.0321

Interpretive Summary: Plant feeding mites cause significant damage to crops and are difficult to control, especially for plants grown under greenhouse conditions. Regular use of chemical pesticides selects for mites with pesticide resistance leaving growers with few options for effective pest management. Plant based essential oils, nootkatone and carvacrol, were shown to have activity as biomiticides against two-spotter spider mite and broad mite pests, even though treatment shortcomings needing additional research were identified. Results presented will direct future research to further development of additional pest control options that are suitable for integration into sustainable strategies for greenhouse systems producing food and ornamental plants.

Technical Abstract: Herbivorous mites are recurrent problems in woody ornamental production and landscape settings. Mites cause damage to leaf tissue through their feeding behavior, salivary excretions and, in the case of spider mites, silk webbing they leave behind. Botanical-based miticides, such as neem oil, are used in both organic and conventional production as rotational products to suppress mite populations. Other plant-based compounds such as nootkatone - an essential oil component of grapefruit and Alaskan yellow cedar - might also serve as an organic miticide in crop production systems. A lignin-encapsulated (LE) nootkatone formulation effective at repelling ticks was tested as a miticide against two-spotted spider mite and broad mite. The LE nootkatone at 1 g AI/L caused mortality of spider mites in the absence of silk. An additional essential oil, carvacrol, was added at 0.1% to the formulation to improve mortality of spider mites in the presence of silk. The LE nootkatone product alone suppressed broad mites to levels equal to neem oil. Both nootkatone and carvacrol have potential as biomiticides, but more work is needed to reduce the phytotoxic effects of current formulations.