Amphitetranychus

Superfamily Tetranychoidea

   Family Tetranychidae

      Subfamily Tetranychinae

        Tribe Tetranychini

          Genus Amphitetranychus

Common names: Fruittree spider mite, Hawthorn spider mite, Red spider mite

Probability of Encounter: High

Quarantine importance: Very high.  The genus Amphitetranychus consists of only 3 described species, all of which were originally described as species of Tetranychus and all of which infest woody dicots.  A. quercivorous (Eharah & Gotoh) and A. savenkoe (Reck) feed on oaks in Japan and Russia, respectively. The remaining species, however, the Fruittree spider mite A. viennensis (Zaqcher) is a significant pest of a variety of fruit trees and ornamentals and of especial concern to quarantine in the USA.

• Hawthorn spider mite or Fruittree spider mite - Amphitetranychus viennensis (Zacher) (= Tetranychus viennensis Zacher, T. crataegi Hirst, Apotetranychus longipenis Ugarov & Nikolskii) attacks apple, apricot, most cherries, peach pear, logan berry, hazel nut, and a variety of ornamentals including poppy, crab apple, oak, and ash in Europe, Turkey, mainland Asia, and Japan.

Diagnosis:

• With 1 pair of paranal setae (h3); setae h2 terminal.

• Empodium split distally into 3 pairs of hairs.

• Empodial spur absent.

• Peritremes anastomosed distally.

Similar taxa.  The empodia have tenent hairs in the Bryobiinae.  Eutetranychini (e.g. species of Eutetranychus) have a claw-like or highly regressed empodium.  Other Tetranychini have either 2 pairs of paranal setae (e.g. Allonychus, Panonychus) or have hooked empodia with proximoventral hairs and the duplex setae of tarsus I distal and adjacent (e.g. Oligonychus) or have an empodial spur and have peritremes recurved distally (Tetranychus).

References

 Baker EW & AE Pritchard.  1960.  The tetranychoid mites of Africa.  Hilgardia 29(11): 455-574.

 Baker EW & DM Tuttle.  1994.  A guide to the spider mites (Tetranychidae) of the United States.  Indira Pub. House, West Bloomfield, MI: 347 pp.

Beard JJ, Walter DE, & Allsopp P.  2003.  Spider Mites of Sugarcane in Australia: A Review of Grass-feeding Oligonychus Berlese (Acari: Prostigmata: Tetranychidae) with the description of four new species.  Australian Journal of Entomology 42: 51-78.

Bolland HR, J Gutierre  & CHW Flechtmann. 1998. World Catalogue of the Spider Mite Family (Acari: Tetranychidae). Brill: Leiden.

Helle W & MW Sabelis (eds.) 1985. Spider Mites, Their Biology, Natural Enemies, and Control, vol. 1A. Elsevier: New York.

Jeppson LR, HH Keifer & EW Baker. 1975. Mites Injurious to Economic Plants, University of California Press: Berkeley

Meyer, M.K.P. 1974.  A revision of the Tetranychidae of Africa (Acari) with a key to the genera of the world.  Dept. Agr. Tech. Serv. Mem. 36: 291 pp.

Meyer, M.K.P. Smith 1987.  African Tetranychidae (Acari: Prostigmata) - with reference to the world genera.  S. Afr. Dept. Agr. Water Supply, Entomol. Mem. No. 69: 175 pp.

Navajas M, J Gutierrez & T Gotoh 1997.  Convergence of molecular and morphological data reveals phylogenetic information in Tetranychus species and allows the restoration of the genus Amphitetranychus (Acari: Tetranychidae).  Bull. Entomol. Res. 87: 283-288.

Navajas M, J Gutierrez,  J Lagnel, G Fauvel, T Gotoh 1999.  DNA sequences and cross-breeding experiments in the hawthorn spider mite Amphitetranychus viennensis reveal high genetic differentiation between Japanese and French populations. Entomologia-Experimentalis-et-Applicata. 1999 February; 90(2): 113-122

Ochoa R, H Aguilar & C Vargas 1994. Phytophagous Mites of Central America: An Illustrated Guide  CATIE, Turrialba, Costa Rica.

Tseng Y-H  1990.  A monograph of the mite family Tetranychidae (Acarina: Trombidiformes) from Taiwan.  Taiwan Museum Special Publication series 9. 224 pp.

Zhang Z-Q.  2003.  Mites of greenhouses: identification, biology and control.  CABI Publishing, Wallingford:  244 pp.