Tetranychus urticae

Koch, 1836

twospotted spider mite, two-spotted spider mite, red spider mite

Tetranychus urticae, the twospotted spider mite, is a minute phytophagous mite and among the most destructive agricultural pests worldwide. measure approximately 0.4 mm and are typically pale green for most of the year, turning red in later . The is extremely , feeding on over 1,100 plant species across 140 . It reproduces through arrhenotokous , with females emerging from fertilized and males from unfertilized eggs. can increase explosively under hot, dry conditions, expanding 70-fold in as few as six days. The species exhibits the highest frequency of resistance among arthropods and was the first chelicerate to have its fully sequenced (2011).

Tetranychus urticae by no rights reserved, uploaded by Murielle Desrois. Used under a CC0 license.

Tetranychus urticae by (c) Aleksey Gnilenkov, some rights reserved (CC BY). Used under a CC-BY license.

Spint (Tetranychus urticae) op paprika by Rasbak. Used under a CC BY-SA 3.0 license.

Pronunciation

How to pronounce Tetranychus urticae: /tɛtrəˈnaɪkʊs ˈɜrtɪsiː/

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Identification

Distinguished from Banks grass mite (Oligonychus pratensis) by spot pattern: T. urticae has well-defined spots restricted to the front half of the , whereas Banks grass mite spots extend the full length of the body, sometimes nearly touching posteriorly. T. urticae produces more extensive webbing than Banks grass mite. Distinguished from carmine spider mite by coloration: carmine spider mite females are consistently red, while T. urticae is typically green or variably red. Microscopic examination required for definitive identification; T. urticae has a haplo- system.

Images

Appearance

females measure approximately 0.4 mm (0.016 in) in length. Body coloration is typically pale green for most of the year, with later developing red coloration. Two large dark pigmented spots are present on either side of the , giving the its . The body is divided into two regions: a small anterior region bearing mouthparts and a large region bearing four pairs of legs in adults. Larvae possess three pairs of legs; nymphs and adults possess four pairs. Adults sometimes spin fine silk webbing on and under leaves. are translucent and pearl-like.

Habitat

Occurs in greenhouse and field systems, including industrial fruit plantations, nurseries, and open and protected vegetable production. Thrives in hot, dry conditions. On plants, inhabits the undersides of leaves where it spins protective silk webbing. In apple orchards, mass occurs in certain years alongside other spider mite . House plants near sunny windows provide favorable microhabitats with elevated temperatures that accelerate development.

Distribution

Originally native to Eurasia; now with worldwide distribution in agricultural systems. Documented across Europe (including Austria, Belgium, Bulgaria, France, Germany, Italy, Netherlands, Spain, United Kingdom, and former USSR regions), Africa (Egypt, Kenya, Madagascar, Morocco, South Africa, and others), Asia (China, India, Iran, Israel, Japan, Pakistan, Philippines, Taiwan, Thailand), Australasia (Australia, New Zealand, Pacific Islands), North America (Canada, USA including Arizona, California, Florida, Texas, Washington), Central America and Caribbean (Mexico, Rica, Cuba), and South America (Argentina, Brazil, Chile, Colombia, Venezuela).

Seasonality

Activity and are temperature-dependent. In temperate regions, mated females survive winter in . In heated greenhouses and on house plants near sunny windows, can develop year-round with times as short as 7–8 days at warm temperatures. Field populations increase rapidly during hot, dry periods. In Texas corn, economic occur primarily from tassel through soft dough stage; once corn reaches full dent, mite feeding does not directly reduce yield.

Diet

herbivore feeding on over 1,100 plant from 140 plant . Documented include Malus domestica (apple), Citrus spp., Vitis vinifera (grape), Solanum lycopersicum (tomato), Capsicum spp. (pepper), Cucumis sativus (cucumber), Fragaria spp. (strawberry), Zea mays (maize), Glycine max (soybean), Rosa spp. (rose), Gossypium spp. (cotton), Withania somnifera, and numerous other vegetables, fruits, and ornamental plants. Feeds by piercing individual leaf with stylet-like mouthparts and removing cell contents, causing characteristic stippling damage.

Host Associations

Malus domestica - herbivoreapple; major pest in orchards
Citrus spp. - herbivore
Vitis vinifera - herbivoregrape
Solanum lycopersicum - herbivoretomato
Capsicum spp. - herbivorepepper
Cucumis sativus - herbivorecucumber
Fragaria spp. - herbivorestrawberry
Zea mays - herbivoremaize/corn
Glycine max - herbivoresoybean
Rosa spp. - herbivorerose
Gossypium spp. - herbivorecotton
Withania somnifera - herbivoremost prevalent pest in India

Life Cycle

Development includes , larva, , deutonymph, and stages. Eggs are translucent and pearl-like. Larvae hatch with three pairs of legs and into nymphs with four pairs of legs. Two nymphal stages (protonymph and deutonymph) occur; deutonymph may display quiescent stages. time is 7–8 days at warm temperatures (+30°C) or 30–36 days depending on temperature. Embryo development takes 15 days at +15°C and 2–3 days at +30°C. Females mature in 6–7 days at +30°C and begin laying eggs. Mated females enter to survive winter.

Behavior

Males exhibit precopulatory including remaining atop quiescent female deutonymphs for hours until adulthood, using chemical cues to recognize and choose between live and dead deutonymphs and between and deutonymph stages. Females demonstrate kin recognition and inbreeding avoidance through mate choice; inbred progeny mature more slowly and have lower reproductive output. Aerial behavior accelerates under declining environmental conditions, higher densities, and acaricide application. Produces extensive silk webbing used for movement between plant parts, predator , deposition substrate, and intraspecific communication.

Ecological Role

Phytophagous pest that reduces plant photosynthetic capability through -by-cell feeding damage. Heavy can cause leaf bronzing, defoliation, plant stunting, and lodging. Serves as prey for numerous natural enemies including predatory mites (Phytoseiulus persimilis, Neoseiulus fallacis, Typhlodromus pyri), lady beetles (including spider mite destroyers), minute pirate bugs, and larvae. overuse disrupts , promoting mite by eliminating and competitors.

Human Relevance

Major agricultural pest causing substantial yield losses in global crop production. Damage appears as stippling, , and reduced photosynthetic capacity; heavy cause leaf bronzing, defoliation, and plant death. Control relies on including with predatory mites, selective miticides, and cultural practices. Has developed resistance to more compounds than any other , including , METI-acaricides, pyridaben, and numerous others. First chelicerate sequenced (2011), serving as model organism for arthropod , plant-herbivore interactions, and pesticide resistance evolution. Genome analysis revealed of synthesis genes from fungi.

Similar Taxa

Oligonychus pratensis (Banks grass mite)Similar and damage on grasses and corn; distinguished by pigmentation spots extending full body length versus restricted to in T. urticae; produces less webbing
Tetranychus cinnabarinus (carmine spider mite)Similar and ; females consistently red versus variable green/red in T. urticae; difficult to distinguish without molecular or detailed morphological analysis
Panonychus ulmi (European red mite)Co-occurs in apple orchards; distinguished by different body shape, coloration, and lack of prominent abdominal spots
Amphytetranychus viennensisCo-occurs in Crimean apple orchards; distinguished by morphological features and preferences