Evaluation of Abamectin as a Potential Chemical Control for the Lychee Erinose Mite (Acari: Eriophyidae), a New Invasive Pest in Florida

Abstract The lychee erinose mite, Aceria litchii (Keifer) (Acari: Eriophyidae), is an important pest of lychee (Litchi chinensis Sonn.; Sapindaceae) 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 to control this mite. Aceria litchii was detected recently 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 on lychee in Florida, abamectin was reported to be effective against A. litchii from other parts of the world. However, it remains unknown whether this acaricide can control the mites inside the erinea effectively and protect the new flush. We investigated whether abamectin alone or in combination with an organosilicone surfactant could control an existing mite infestation. Lychee leaflets that had erinea were sprayed with acaricides, then placed on uninfested plants and monitored for symptom development. One mo 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 more precise evaluations of other acaricides that are urgently needed to control A. litchii in Florida.