Detection of the lychee erinose mite, Aceria litchii (Keifer) (Acari: Eriophyidae) in Florida, USA: A comparison with alien populations

Authors: CARRILLO, DANIEL - University Of Florida; CRUZ, LUISA - University Of Florida; REVYNTHI, ALEXANDRA - University Of Florida; DUNCAN, RITA - University Of Florida; Bauchan, Gary; Ochoa, Ronald - Ron; Kendra, Paul; BOLTON, SAMUEL - Florida Department Of Agriculture And Consumer Services

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2020
Publication Date: 4/9/2020
Publication URL: https://handle.nal.usda.gov/10113/6934609
Citation: Carrillo, D., Cruz, L.F., Revynthi, A.M., Duncan, R.E., Bauchan, G.R., Ochoa, R., Kendra, P.E., Bolton, S.J. 2020. Detection of the lychee erinose mite, Aceria litchii (Keifer) (Acari: Eriophyidae) in Florida, USA: A comparison with alien populations. Insects. 11(4):235. https://doi.org/10.3390/insects11040235.
DOI: https://doi.org/10.3390/insects11040235

Interpretive Summary: The lychee erinose mite (LEM, Aceria litchii) is one of the most serious pests of lychee trees in Southeast Asia, Brazil, Australia, and Hawaii. The microscopic mite infests young leaves, stems, and flowers, where feeding causes galls known as erinea. Heavy LEM infestations can result in 70-80% reduction in yield and 20% increase in production costs. In February 2018, LEM was discovered in Pine Island, Lee County, Florida, and subsequently spread to other counties, prompting quarantine and eradication efforts within the state. As part of initial research to understand this new pest, scientists from the University of Florida, Florida Department of Agriculture and Consumer Services, and USDA-ARS (Beltsville, MD and Miami, FL) conducted a study to compare the genotype of Florida LEM to specimens obtained from India, Hawaii, Brazil, Taiwan, and Australia. The molecular analysis separated the mites into two lineages, with one group from Australia and a second group from Hawaii, India, Brazil, Taiwan and Florida. LEM from Taiwan and Florida were identical in the genetic sequences analyzed, suggesting a common origin. This information will be used by scientists and regulatory agencies to determine the origin of the Florida population and aid in pathway risk analysis for this destructive, invasive pest.

Technical Abstract: The Lychee Erinose Mite (LEM), Aceria litchii (Keifer) is a serious pest of lychee (Litchi chinensis Sonn.). LEM causes a type of gall called an erineum (abnormal felty growth of trichomes from the epidemis), where it feeds, reproduces and protects itself from biotic and abiotic adversities. In February of 2018 LEM was found in a commercial lychee orchard on Pine Island, Florida. Infestations were recorded on young leaves, stems, and inflorescences of approximately 30 young trees (1.5-3.0 yrs.) of three lychee varieties presenting abundant new growth. Although LEM is present in Hawaii, this mite is a prioritized quarantine pest in the continental U.S.A. and its territories. Florida LEM specimens showed small morphological differences from the original descriptions of Keiffer (1943) and Huang (2008). A molecular comparison of LEM specimens from India, Hawaii, Brazil, Taiwan, Australia and Florida was made. The amplified COI fragment showed very low nucleotide variation among the locations and could be used for accurate LEM identification. The ITS1 sequences and partial 5.8S fragments displayed no nucleotides differences for specimens from any of the locations except for Australia. Consistent differences were observed in the ITS2 and 28S fragments. The ITS1- ITS2 concatenated phylogeny yielded two lineages with Australia in one group and Hawaii, India, Brazil, Florida and Taiwan in another group. Specimens from Taiwan and Florida seem to present identical ITS and rDNA segments, perhaps indicating a common origin; however, analysis of additional sequences is needed to confirm the origin of the Florida population.