Evaluation of abamectin as a potential chemical control for the lychee erinose mite (Acari: eriophyidae), a new invasive pest in Florida

Authors: REVYNTHI, ALEXANDRA - University Of Florida; CRUZ, LUISA - University Of Florida; CANNON, MARIA - University Of Florida; CRANE, JONATHAN - University Of Florida; Kendra, Paul; MANNION, CATHARINE - University Of Florida; CARRILLO, DANIEL - University Of Florida

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2021
Publication Date: 4/12/2022
Citation: Revynthi, A.M., Cruz, L.F., Cannon, M.A., Crane, J.A., Kendra, P.E., Mannion, C., Carrillo, D. 2022. Evaluation of abamectin as a potential chemical control for the lychee erinose mite (Acari: eriophyidae), a new invasive pest in Florida. Florida Entomologist. 105(1):1-5. https://doi.org/10.1653/024.105.0101.
DOI: https://doi.org/10.1653/024.105.0101

Interpretive Summary: The lychee erinose mite (LEM) (Aceria litchii) is a serious pest of lychee trees in Asia and other geographic regions where this pest has been introduced. This minute mite prefers to feed on young, new flush causing the formation of galls called “erinea” and preventing flowering and fruit production. Chemical control to protect new flush is the primary management approach that has been used against this mite. LEM was recently detected in Lee County, Florida, USA, and there is an urgent need to identify an acaricide that can control mite populations. Among the acaricides registered for use in lychee in Florida, abamectin was reported to be effective against LEM in other parts of the world. However, it remains unknown whether this acaricide can effectively control mites inside the erinea and protect the new flush. Therefore, scientists from the University of Florida (Homestead) and the USDA-ARS (Miami) investigated whether abamectin alone or in combination with an organosilicone surfactant could control an existing mite infestation by spraying lychee leaflets with erinea, placing treated leaflets on uninfested plants, and monitoring for symptom development. One month after placing treated leaflets on uninfested plants, the same treatment was applied to the whole plants and monitored for erinea development on the new flush. Results indicate that none of the treatments were effective for control of the mites inside the erinea and protection of the new flush. Therefore, additional acaricides need to be evaluated for efficacy, and the methods described herein can be used for realistic evaluations of other acaricides that are urgently needed for control LEM in Florida.

Technical Abstract: The lychee erinose mite (LEM) (Aceria litchii) is an important pest of lychee trees. This minute mite prefers to feed on young, new flush causing the formation of galls called “erinea”. Chemical control to protect the new flush is the primary management approach that has been used against this mite. LEM was recently detected in Lee County, Florida, USA, and there is an urgent need to identify an acaricide that can control mite populations. Among the acaricides registered for use in lychee in Florida, abamectin was reported to be effective against LEM in other parts of the world. However, it remains unknown whether this acaricide can effectively control the mites inside the erinea and protect the new flush. We investigated whether abamectin alone or in combination with an organosilicone surfactant could control an existing mite infestation by spraying lychee leaflets with erinea, placing treated leaflets on uninfested plants, and monitoring for symptom development. One month after placing treated leaflets on uninfested plants, the same treatment was applied to the whole plants and monitored for erinea development on the new flush. Our results showed that none of the treatments were able to control the mites inside the erinea and protect the new flush. The methods described here can be used for realistic evaluations of other acaricides that are urgently needed to control LEM in Florida.