Detection of the Lychee Erinose Mite, Aceria litchii (Keifer) (Acari: Eriophyidae) in Florida, USA: A Comparison with Other Alien Populations.

Gary R. Bauchan,Samuel J. Bolton,Paul E. Kendra,Ronald Ochoa,Daniel Carrillo,Alexandra M. Revynthi,Rita E. Duncan,Luisa F. Cruz

doi:10.3390/insects11040235

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 ‘erineum’ (abnormal felty growth of trichomes from the epidermis), 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 USA and its territories. Florida LEM specimens showed small morphological differences from the original taxonomic descriptions of Keifer (1943) and Huang (2008). The observed differences are probably an artifact of the drawings in the original descriptions. Molecular comparisons were conducted on the DNA of LEM specimens from India, Hawaii, Brazil, Taiwan, Australia and Florida. The amplified COI fragment showed very low nucleotide variation among the locations and thus, could be used for accurate LEM identification. The ITS1 sequences and partial 5.8S fragments displayed no nucleotide differences for specimens from any of the locations except 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. Specimens from Taiwan and Florida present identical ITS and rDNA segments, suggesting a common origin; however, analysis of additional sequences is needed to confirm the origin of the Florida population.

Highlights

The Lychee Erinose Mite (LEM), Aceria litchii (Keifer) (Acari: Eriophyidae) is one of the most important pests of lychee trees (Litchi chinensis Sonn., Sapindaceae) in Asia
Lychee erinose mites were freshly collected from Hawaii and Florida, preserved in 70% ethanol and examined under Low-Temperature SEM (LTSEM), following the technique delineated by Bolton et al [22]
Amplification of the cytochrome oxidase subunit I (COI) was carried out with the primer and conditions reported by Navajas et al [24].The internal transcribed spacer 1 (ITS1) along with the 50 terminal region of 5.8S were amplified with the primer sets and conditions reported by Fenton et al [25]

Summary

Introduction

The Lychee Erinose Mite (LEM), Aceria litchii (Keifer) (Acari: Eriophyidae) is one of the most important pests of lychee trees (Litchi chinensis Sonn., Sapindaceae) in Asia. The mite has been reported from Hawaii [6] and Australia [7]. Insects 2020, 11, 235 spread to all major lychee producing areas and has caused an estimated 70%–80% yield reduction and a 20% increase in production costs [9]. An 80% yield reduction caused by LEM was reported in India [10]. LEM is present in Hawaii [6], this mite is a prioritized quarantine pest in the continental

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