Acathrix trymatus Keifer in Florida

Coconuts, Cocos nucifera (Arecaceae), are an important world crop. In Florida, coconut palms are used as an important part of tropical landscapes. Coconut palms are hosts to at least 12 species of Eriophyidae in nine genera worldwide. Three species of eriophyid mites have been found on Florida coconut palms (Keifer 1962a, c; 1965). Keifer (1962a, c) described two species in 1962: Acritonotus denmarki Keifer and Amrinus coconuciferae (Keifer). Amrinus coconuciferae was originally placed in the genus Acamina by Keifer (1962a), but was transferred to Amrinus by Flechtmann (1994). This mite is a leaf vagrant and is not known to damage coconut palms or their fruit. Acritonotus denmarki Keifer, was described from a Florida royal palm (Roystonis elata), and can damage fronds (Keifer 1962c) of the royal and coconut palms. A third species, Aceria guerreronis Keifer was described in 1965 from coconuts in Mexico (Keifer 1965) and confirmed in Florida in 1984 (Howard et al. 1990). The coconut mite, A. guerreronis, damages floral bracts and scars developing coconuts in West Africa, Brazil, and throughout the Carribean region, including Mexico, Colombia, and Venezuela (Howard et al. 1990).

In 1996, a fourth eriophyid mite, Acathrix trymatus, was discovered on the newly emerging coconut fronds on Grassy Key (Monroe County) by Mr. Jon G. Rackley. Acathrix trymatus was originally described by Keifer (1962b) from specimens collected in the folds of newly emerging coconut fronds in the Philippines. Keifer’ s generic name, Acathrix, means “short seta” for the minute scapular setae on the prodorsal sclerite of this species (Keifer 1962b). Briones (1963) investigated A. trymatus and three other eriophyid species on Philippine coconut palms and found their feeding did little damage and did not transmit cadang-cadang disease.