Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Tetranychus pacificus
(Pacific spider mite)



Tetranychus pacificus (Pacific spider mite)


  • Last modified
  • 22 November 2019
  • Datasheet Type(s)
  • Pest
  • Preferred Scientific Name
  • Tetranychus pacificus
  • Preferred Common Name
  • Pacific spider mite
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Arthropoda
  •       Subphylum: Chelicerata
  •         Class: Arachnida

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Pacific spider mite, adult female.
CaptionPacific spider mite, adult female.
CopyrightRachid Hanna
Pacific spider mite, adult female.
AdultPacific spider mite, adult female.Rachid Hanna
Damage to grapevines caused by Pacific spider mite.
TitleDamage symptoms
CaptionDamage to grapevines caused by Pacific spider mite.
CopyrightRachid Hanna
Damage to grapevines caused by Pacific spider mite.
Damage symptomsDamage to grapevines caused by Pacific spider mite.Rachid Hanna
A large 'hot spot' of severe Pacific spider mite damage in a grape vineyard (yellowed area).
TitleDamage symptoms
CaptionA large 'hot spot' of severe Pacific spider mite damage in a grape vineyard (yellowed area).
CopyrightRachid Hanna
A large 'hot spot' of severe Pacific spider mite damage in a grape vineyard (yellowed area).
Damage symptomsA large 'hot spot' of severe Pacific spider mite damage in a grape vineyard (yellowed area).Rachid Hanna
Adult phytoseiid predatory mite.
TitleNatural enemy
CaptionAdult phytoseiid predatory mite.
CopyrightRachid Hanna
Adult phytoseiid predatory mite.
Natural enemyAdult phytoseiid predatory mite.Rachid Hanna


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Preferred Scientific Name

  • Tetranychus pacificus McGregor

Preferred Common Name

  • Pacific spider mite

International Common Names

  • English: Pacific mite
  • Spanish: arana roja del pacifico
  • French: tetranyque du Pacifique

Local Common Names

  • USA: Pacific mite

EPPO code

  • TETRPA (Tetranychus pacificus)

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Arthropoda
  •             Subphylum: Chelicerata
  •                 Class: Arachnida
  •                     Subclass: Acari
  •                         Superorder: Acariformes
  •                             Suborder: Prostigmata
  •                                 Family: Tetranychidae
  •                                     Genus: Tetranychus
  •                                         Species: Tetranychus pacificus

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 10 Jan 2020

Growth Stages

Top of page Flowering stage, Fruiting stage, Post-harvest, Seedling stage, Vegetative growing stage

List of Symptoms/Signs

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SignLife StagesType
Leaves / abnormal colours
Leaves / external feeding
Stems / distortion
Stems / webbing
Whole plant / early senescence

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Amblyseius addoensis Predator Adults/Nymphs
Amblyseius andersoni Predator Adults/Nymphs
Amblyseius citri Predator Adults/Nymphs
Amblyseius citrifolius Predator Adults/Nymphs
Amblyseius degenerans Predator Adults/Nymphs
Bdella longicornis Predator Adults/Nymphs
Euseius hibisci Predator Adults/Nymphs
Euseius scutalis Predator Adults/Nymphs
Euseius stipulatus Predator Adults/Nymphs
Euseius tularensis Predator Adults/Nymphs
Frankliniella occidentalis Predator Adults/Nymphs
Galendromus annectens Predator Adults/Nymphs
Geocoris pallens Predator Adults/Nymphs
Metaseiulus occidentalis Predator Adults/Nymphs California
Orius tristicolor Predator Adults/Nymphs
Phytoseiulus longipes Predator Adults/Nymphs
Phytoseiulus persimilis Predator Adults/Nymphs
Stethorus punctum picipes Predator Adults/Nymphs
Typhlodromus persianus Predator Adults/Nymphs
Typhlodromus pini Predator Adults/Nymphs
Typhlodromus porresi Predator Adults/Nymphs
Typhlodromus validus Predator Adults/Nymphs


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Ahumada MH, Mitcham EJ, Moore DG, 1996. Postharvest quality of 'Thompson Seedless' grapes after insecticidal controlled-atmosphere treatments. HortScience, 31(5):833-836; 36 ref

Andrews KL, Pre LFLa, 1979. Effects of Pacific spider mite on physiological processes of almond foliage. Journal of Economic Entomology, 72(5):651-654

Bai LX, 1993. Preliminary studies on the demography of the Pacific spider mite, Tetranychus pacificus (Acari: Tetranychidae) on cotton. Polish Ecological Studies, 19(1-2):45-58

Bai LX, Carey JR, 1988. Laboratory studies on demography of Pacific spider mite (T. pacificus) on cotton leaf. Jiangsu Journal of Agricultural Sciences, 4(3):29-37

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

Bentley WJ, Zalom F, Granett, J, Smith RJ, Varela L, Purcell A, 2000. UC IPM Pest Management Guidelines: Grape. C DANR Publication 3339. (

Bolland HR, Gutierrez J, Flechtmann CHW, 1998. World Catalogue of the Spider Mite Family (Acari: Tetranychidae). Leiden, Netherlands: K. Brill, 392 pp

CABI/EPPO, 2011. Tetranychus pacificus. [Distribution map]. Distribution Maps of Plant Pests, No.June. Wallingford, UK: CABI, Map 752

Carey JR, Bradley JW, 1982. Developmental rates, vital schedules, sex ratios and life tables for Tetranychus urticae, T. turkestani and T. pacificus (Acarina: Tetranychidae) on cotton. Acarologia, 23(4):333-345

Corbett A, Leigh TF, Wilson LT, 1991. Interplanting alfalfa as a source of Metaseiulus occidentalis (Acari: Phytoseiidae) for managing spider mites in cotton. Biological Control, 1(3):188-196

Dennehy TJ, Granett J, 1984. Spider mite resistance to dicofol in San Joaquin Valley cotton: inter- and intraspecific variability in susceptibility of three species of Tetranychus (Acari: Tetranychidae). Journal of Economic Entomology, 77(6):1381-1385

Dennehy TJ, Granett J, Leigh TF, Colvin A, 1987. Laboratory and field investigations of spider mite (Acari: Tetranychidae) resistance to the selective acaricide propargite. Journal of Economic Entomology, 80(3):565-574

English-Loeb G, Karban R, Walker MA, 1998. Genotypic variation in constitutive and induced resistance in grapes against spider mite (Acari: Tetranychidae) herbivores. Environmental Entomology, 27(2):297-304; 34 ref

English-Loeb GM, Flaherty DL, Wilson LT, Barnett WW, Leavitt GM, Settle WH, 1986. Pest management affects spider mites in vineyards. California Agriculture, 40(3-4):28-30

English-Loeb GM, Karban R, Hougen-Eitzman D, 1993. Direct and indirect competition between spider mites feeding on grapes. Ecological Applications, 3(4):699-707; 35 ref

Flaherty DL, Hoy MA, 1972. Biological control of Pacific mites and Willamette mites in San Joaquin Valley vineyards. III. Role of tydeid mites. Researches on Population Ecology, 8:80-96

FLAHERTY DL, HUFFAKER CB, 1970. Biological control of Pacific mites and Willamette mites in San Joaquin Valley vineyards. I. Role of Metaseiulus occidentalis. Hilgardia, 40(10):267-308 pp

Flaherty DL, Wilson LT, Welter S, Lynn CD, Hanna R, 1992. Spider mites, In: Flaherty DL, Christensen PL, Lannini T, Marois J, Wilson LT, eds. Grape Pest Management. University of California Division of Agriculture and Natural Resources. Publication 3343, 181-192

Gilstrap FE, Ortman RE, 1976. The bionomics of Scolothrips sexmaculatus (Pergande) (Thysanoptera: thripidae), an insect predator of spider mites. Hilgardia, 44(2):27-59

Grafton-Cardwell EE, Granett J, Leigh TF, 1987. Spider mite species (Acari: Tetranychidae) response to propargite: basis for an acaricide resistance management program. Journal of Economic Entomology, 80(3):579-587

Grafton-Cardwell EE, Granett J, Normington SM, 1991. Influence of dispersal from almonds on the population dynamics and acaricide resistance frequencies of spider mites infesting neighboring cotton. Experimental & Applied Acarology, 10(3-4):187-212

Hanna R, Wilson LT, 1991. Prey preference by Metaseiulus occidentalis (Acari: Phytoseiidae) and the role of prey aggregation. Biological Control, 1(1):51-58

Hanna R, Wilson LT, Zalom FG, Flaherty DL, 1997. Effects of predation and competition on the population dynamics of Tetranychus pacificus on grapevines. Journal of Applied Ecology, 34(4):878-888; 40 ref

Hanna R, Wilson LT, Zalom FG, Flaherty DL, Leavitt GM, 1996. Spatial and temporal dynamics of spider mites (Acari: Tetranychidae) in 'Thompson Seedless' vineyards. Environmental Entomology, 25(2):370-382; 36 ref

Hanna R, Zalom FG, Elmore CL, 1995. Integration of cover crops in grapevine pest and nutrition management: the transition phase. University of California Sustainable Agriculture Research and Education Program Technical Reviews, Summer 1995

Hanna R, Zalom FG, Wilson LT, 1997. 'Thompson seedless' grapevine vigour and abundance of Pacific spider mite (Tetranychus pacificus McGregor) (Acari, Tetranychidae). Journal of Applied Entomology, 121(9/10):511-516; 27 ref

Hanna R, Zalom FG, Wilson LT, Leavitt GM, 1997. Sulfur can suppress mite predators in vineyards. California Agriculture, 51(1):19-21

Helle W, Sabelis MW (Editors), 1985. Spider mites. Their biology, natural enemies and control. Vol. 1A. Amsterdam, Netherlands: Elsevier, 405 pp

Helle W, Sabelis MW (Editors), 1985. Spider mites. Their biology, natural enemies and control. Vol. 1B. Amsterdam, Netherlands: Elsevier, 458 pp

Hougen-Eitzman D, Karban R, 1995. Mechanisms of interspecific competition that result in successful control of Pacific mites following inoculations of Willamette mites on grapevines. Oecologia, 103(2):157-161

Hoy MA, Conley J, 1987. Toxicity of pesticides to western predatory mite. California Agriculture, 41(7-8):12-14

Hoy MA, Conley J, 1989. Propargite resistance in Pacific spider mite (Acari: Tetranychidae): stability and mode of inheritance. Journal of Economic Entomology, 82(1):11-16

Hoy MA, Standow KA, 1981. Resistance to sulfur in a vineyard spider mite predator. California Agriculture, 35(516):8-10

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

Karban R, 1986. Induced resistance against spider mites in cotton: field verification. Entomologia Experimentalis et Applicata, 42(3):239-242

Karban R, English-Loeb G, Hougen-Eitzman D, 1997. Mite vaccinations for sustainable management of spider mites in vineyards. Ecological Applications, 7(1):183-193; 36 ref

Karban R, English-Loeb GM, 1990. A 'vaccination' of Willamette spider mites (Acari: Tetranychidae) to prevent large populations of Pacific spider mites on grapevines. Journal of Economic Entomology, 83(6):2252-2257

Karban R, Hougen-Eitzmann D, English-Loeb G, 1994. Predator-mediated apparent competition between two herbivores that feed on grapevines. Oecologia, 97(4):508-511

Keena MA, Grafton-Cardwell E, Granett J, 1991. Variability in response of laboratory-reared and field-collected populations of Tetranychus spp. (Acari: Tetranychidae) to hexythiazox. Journal of Economic Entomology, 84(4):1128-1134

Keena MA, Granett J, 1987. Cyhexatin and propargite resistance in populations of spider mites (Acari: Tetranychidae) from California almonds. Journal of Economic Entomology, 80(3):560-564

Kinn DN, Doutt RL, 1972. Initial survey of arthropods found in north coast vineyards of California. Environmental Entomology, 1(4):508-513

Kinn DN, Doutt RL, 1972. Natural control of spider mites on wine grape varieties in Northern California. Environmental Entomology, 1(4):513-518

Kinn DN, Joos JL, Doutt RL, Sorensen JT, Foskett MJ, 1974. Effects of Tetranychus pacificus and irrigation practices on yield and quality of grapes in north coast vineyards of California. Environmental Entomology, 3(4):601-606

Knop NF, Hoy MA, 1983. Factors limiting the utility of Homeopronematus anconai (Acari: Tydeidae) in integrated pest management in San Joaquin Valley vineyards. Journal of Economic Entomology, 76(5):1181-1186

Laing JE, Calvert DL, Huffaker CB, 1972. Preliminary studies of effects of Tetranychus pacificus on yield and quality of grapes in the San Joaquin Valley, California. Environmental Entomology, 1(5):658-663

Lamiman JF, 1935. The Pacific mite, Tetranychus pacificus McGregor, in California. Journal of Economic Entomology, 28:900-903

Loeb-English GM, Karban R, 1988. Negative interactions between Willamette mites and Pacific mites: possible management strategies for grapes. Entomologia Experimentalis et Applicata, 48(3):269-274

Mabry J, Walton MM, 1939. Distribution and food plant records of Paratetranychus citri McGregor, P. ilicie McGregor, P. pilosus C.&F., Tetranychus pacificus McGregor and T. telarius L. Insect Pest Survey Bull., 19(Supplement No. 9):589-602

Mosaki M, Hayase T, Miyajima S, 1991. Notes on eight species of spider mites and predacious thrips intercepted on squash imported from USA, Mexico, Colombia and New Zealand. Research Bulletin of the Plant Protection Service, Japan, No. 27:107-114

Newcomer E J, 1954. Identity of Tetranychus pacificus and mcdanieli. Journal of Economic Entomology, 47(3):460-462

Oi DH, Barnes MM, 1989. Predation by the western predatory mite (Acari: Phytoseiidae) on the Pacific spider mite (Acari: Tetranychidae) in the presence of road dust. Environmental Entomology, 18(5):892-896

Oi DH, Sanderson JP, Youngman RR, Barnes MM, 1989. Developmental times of the Pacific spider mite (Acari: Tetranychidae) on water-stressed almond trees Environmental Entomology, 18(2):208-212

PRITCHARD AE, BAKER EW, 1955. Mem. Pacif. Coast ent. Soc, 2. San Francisco, Cal., 7 + 472 pp

Roush RT, Peacock WL, Flaherty DL, Hoy MA, 1980. Dimethoate-resistant spider mite predator survives field tests. California Agriculture, 34(5):12-13

Seney H(Editor), 1984. Integrated pest management for cotton in the western region of the United States. Publication, Division of Agriculture and Natural Resources, University of California, No. 3305:144pp

Trichilo PJ, Leigh TF, 1985. The use of life tables to assess varietal resistance of cotton to spider mites. Entomologia Experimentalis et Applicata, 39(1):27-33

Trichilo PJ, Leigh TF, 1986. Predation on spider mite eggs by the western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), an opportunist in a cotton agroecosystem. Environmental Entomology, 15(4):821-825

Trichilo PJ, Leigh TF, 1986. The impact of cotton plant resistance on spider mites and their natural enemies. Hilgardia, 54(5):1-20

UCIPM, 1985. Degree-day models for important mite and insect pests of California crops. University of California Statewide IPM Project

UCIPM, 1985. Integrated management for almonds. Integrated management for cotton in the western region of the United States. University of California Division of Agriculture and Natural Resources. Publication 3308

Welter SC, Barnes MM, Ting IP, Hayashi JT, 1984. Impact of various levels of late-season spider mite (Acari: Tetranychidae) feeding damage on almond growth and yield. Environmental Entomology, 13(1):52-55

Welter SC, Farnham DS, McNally PS, Freeman R, 1989. Effect of Willamette mite and Pacific spider mite (Acari: Tetranychidae) on grape photosynthesis and stomatal conductance. Environmental Entomology, 18(6):953-957

Welter SC, McNally PS, Farnham DS, 1989. Effect of Willamette mite (Acari: Tetranychidae) on grape productivity and quality: a reappraisal. Environmental Entomology, 18(3):408-411

Wilson LT, Gonzalez D, Leigh TF, Maggi V, Foristiere C, Goodell P, 1983. Within-plant distribution of spider mites (Acari: Tetranychidae) on cotton: a developing implementable monitoring program. Environmental Entomology, 12(1):128-134

Wilson LT, Hoy MA, Zalom FG, Smilanick JM, 1984. Sampling mites in almonds: I. Within-tree distribution and clumping pattern of mites with comments on predator-prey interactions. Hilgardia, 52(7):1-13

Wilson LT, Smilanick JM, Hoffmann MP, Flaherty DL, Ruiz SM, 1988. Leaf nitrogen and position in relation to population parameters of Pacific spider mite, Tetranychus pacifus (Acari: Tetranychidae) on grapes. Environmental Entomology, 17(6):964-968

Youngman RR, Barnes MM, 1986. Interaction of spider mites (Acari: Tetranychidae) and water stress on gas-exchange rates and water potential of almond leaves. Environmental Entomology, 15(3):594-600

Youngman RR, Sanderson JP, Barnes MM, 1988. Life history parameters of Tetranychus pacificus McGregor (Acari: Tetranychidae) on almonds under differential water stress. Environmental Entomology, 17(3):488-495

Zalom FG, Wilson LT, Hoy MA, Barnett WW, Smilanick JM, 1984. Sampling Tetranychus spider mites in almonds. California Agriculture, 38(5/6):17-19

Distribution Maps

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