Spider mites are members of the Acari (mite) family Tetranychidae, which includes about 1,200 species. They generally live on the under sides of leaves

Leaf

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

 of plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s, where they may spin protective silk webs

Spider web

A spider web, spiderweb, spider's web or cobweb is a device built by a spider out of proteinaceous spider silk extruded from its spinnerets....

, and they can cause damage by puncturing the plant cells

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 to feed. Spider mites are known to feed on several hundred species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of plant.

Description

Spider mites are less than 1 millimetre (0.0393700787401575 in) in size and vary in colour. They lay small, spherical, initially transparent eggs

Egg (biology)

An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

 and many species spin silk webbing to help protect the colony

Colony (biology)

In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...

 from predators

Predation

In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...

; they get the 'spider' part of their common name from this webbing.

Life cycle

Hot, dry conditions are often associated with population build-up of spider mites. Under optimal conditions (approximately 80 °F or 26.7 °C), the two-spotted spider mite can hatch in as little as 3 days, and become sexually mature in as little as 5 days. One female can lay up to 20 eggs per day and can live for 2 to 4 weeks, laying hundreds of eggs. A single mature female can spawn a population of a million mites in a month or less. This accelerated reproductive rate allows spider mite populations to adapt quickly to resist pesticides

Pesticide resistance

Pesticide resistance is the adaptation of pest population targeted by a pesticide resulting in decreased susceptibility to that chemical. In other words, pests develop a resistance to a chemical through natural selection: the most resistant organisms are the ones to survive and pass on their...

, so chemical control methods can become somewhat ineffectual when the same pesticide is used over a prolonged period.

Spider mites, like hymenoptera

Hymenoptera

Hymenoptera is one of the largest orders of insects, comprising the sawflies, wasps, bees and ants. There are over 130,000 recognized species, with many more remaining to be described. The name refers to the heavy wings of the insects, and is derived from the Ancient Greek ὑμήν : membrane and...

ns and some homopterous

Homoptera

Homoptera is a deprecated suborder of order Hemiptera; recent morphological studies and DNA analysis strongly suggests that the order is paraphyletic. It was therefore split into the suborders Sternorrhyncha, Auchenorrhyncha, and Coleorrhyncha....

 insects, are arrhenotochous

Arrhenotoky

Arrhenotoky or arrhenotokous parthenogenesis is a form of parthenogenesis in which unfertilized eggs develop into haploid males.This form is observed in some marine invertebrates, beetles, scorpions, mites, bees, etc....

: females are diploid and males are haploid. When mated, females avoid the fecundation of some eggs to produce males. Fertilized eggs produce diploid females. Unmated, unfertilized females still lay eggs, that originate exclusively haploid males.

Genera

The best known member of the group is Tetranychus urticae

Tetranychus urticae

Tetranychus urticae is one of many species of plant-feeding mites found in dry environments across the world, and generally considered a pest. It is the most widely known member of the family Tetranychidae or spider mites...

, which has a cosmopolitan distribution

Cosmopolitan distribution

In biogeography, a taxon is said to have a cosmopolitan distribution if its range extends across all or most of the world in appropriate habitats. For instance, the killer whale has a cosmopolitan distribution, extending over most of the world's oceans. Other examples include humans, the lichen...

, and attacks a wide range of plants, including peppers

Capsicum

Capsicum is a genus of flowering plants in the nightshade family, Solanaceae. Its species are native to the Americas where they have been cultivated for thousands of years, but they are now also cultivated worldwide, used as spices, vegetables, and medicines - and have become are a key element in...

, tomatoes, potato

Potato

The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...

es, bean

Bean

Bean is a common name for large plant seeds of several genera of the family Fabaceae used for human food or animal feed....

s, corn

Maize

Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...

, Marijuana, strawberries

Strawberry

Fragaria is a genus of flowering plants in the rose family, Rosaceae, commonly known as strawberries for their edible fruits. Although it is commonly thought that strawberries get their name from straw being used as a mulch in cultivating the plants, the etymology of the word is uncertain. There...

. Other species which can be important pests of commercial plants include Panonychus ulmi

Panonychus ulmi

Panonychus ulmi, the European red mite, is a species of mite which is a major agricultural pest of fruit trees. It has a high reproductive rate, a short generation time and produces many broods in a year, all of which contribute to its pest status...

(fruit tree red spider mite) and Panonychus citri (citrus red mite).

The family is divided into the following subfamilies, tribes

Tribe (biology)

In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...

 and genera

Genera

Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...

:

Bryobinae Berlese

• Bryobini Reck
• Neoschizonobiella Tseng
• Sinobryobia Ma et al.
• Marainobia Meyer
• Bryobia Koch
• Toronobia Meyer
• Pseudobryobia McGregor
• Strunkobia Livshitz & Mitrofanov
• Mezranobia Athias-Henriot
• Eremobryobia Strunkova & Mitrofanov
• Bryobiella Tuttle & Baker
• Hemibryobia Tuttle & Baker

• Hystrichonychini Pritchard & Baker
• Bryocopsis Meyer
• Tetranychopsis Canestrini
• Notonychus Davis
• Dolichonobia Meyer
• Monoceronychus McGregor
• Mesobryobia Wainstein
• Hystrichonychus McGregor
• Parapetrobia Meyer & Rykev
• Peltanobia Meyer
• Tauriobia Livshitz & Mitrofanov
• Aplonobia Womersley
• Paraplonobia Wainstein
• Beerella Wainstein
• Magdalena Baker & Tuttle
• Porcupinychus Anwarullah
• Afronobia Meyer

• Petrobiini Reck
• Neotrichobia Tuttle & Baker
• Schizonobiella Beer & Lang
• Schizonobia Womersley
• Dasyobia Strunkova
• Lindquistiella Mitrofanov
• Edella Meyer
• Petrobia Murray

Tetranychinae Berlese

• Eurytetranychini Reck
• Atetranychus Tuttle et al.
• Synonychus Miller
• Eurytetranychus Oudemans
• Eurytetranychoides Reck
• Eutetranychus Banks
• Meyernychus Mitrofanov
• Aponychus Rimando
• Paraponychus Gonzalez & Flechtmann
• Sinotetranychus Ma & Yuan
• Anatetranychus Womersley
• Duplanychus Meyer

• Tenuipalpoidini Pritchard & Baker
• Eonychus Gutierrez
• Crotonella Tuttle et al.
• Tenuipalpoides Reck & Bagdasarian
• Tenuipalponychus Channabasavanna & Lakkundi

• Tetranychini Reck
• Brevinychus Meyer
• Sonotetranychus Tuttle et al.
• Mixonychus Meyer & Ryke
• Evertella Meyer
• Panonychus Yokoyama
• Allonychus Pritchard & Baker
• Schizotetranychus Trägårdh
• Yunonychus Ma & Gao
• Yezonychus Ehara
• Neotetranychus Trägårdh
• Acanthonychus Wang
• Mononychellus Wainstein
• Platytetranychus Oudemans
• Eotetranychus Oudemans
• Palmanychus Baker & Tuttle
• Atrichoproctus Flechtmann
• Xinella Ma & Wang
• Oligonychus Berlese
• Hellenychus Gutierrez
• Tetranychus
  Tetranychus
  Tetranychus is a genus of spider mite. Tetranychus is one of the most economically important genera of mites, due to its high potential to destroy agriculture. It contains over 140 species, the most significant of which are Tetranychus urticae and Tetranychus cinnabarinus....
  
  Dufour
• Amphitetranychus Oudemans

Countermeasures

Chemical control of spider mites generally involves pesticides that are specifically developed for spider mite control (miticide

Miticide

Acaricides are pesticides that kill members of the Acari group, which includes ticks and mites.Acaricides are used both in medicine and agriculture, although the desired selective toxicity differs between the two fields.-Terminology:...

s or acaricides). Few insecticides are effective for spider mites and many even aggravate problems. Furthermore, most spider mites become resistant to new pesticides within two to four years, making control difficult. Because most miticides do not affect eggs, a repeat application at an approximately 10- to 14-day interval is usually needed for control. Since an egg can develop into a mature spider mite able to lay eggs of its own in as little as 9 days, more frequent application may be required in hot, dry conditions. Neem oil

Neem oil

Neem oil is a vegetable oil pressed from the fruits and seeds of the neem , an evergreen tree which is endemic to the Indian subcontinent and has been introduced to many other areas in the tropics...

 may provide control, when combined with a suitable surfactant and diluted with water. As with chemical control, repeated applications are required.

Various insects and predatory mites feed on spider mites and provide a high level of natural control. One group of small, dark-coloured lady beetles (Stethorus species) are specialised predators of spider mites. Minute pirate bugs (Orius

Orius

The genus Orius consists of omnivorous bugs in the family Anthocoridae . Adults are 2–5 mm long and feed mostly on spider mites, thrips, and their eggs, but will also feed on pollen and vascular sap .These predators are common in gardens and landscapes...

; family Anthocoridae

Anthocoridae

The Anthocoridae are a family of bugs, commonly called minute pirate bugs or flower bugs.-Name:The vernacular name probably stems from the notion that these very small animals can do much pain to humans, just like small pirate vessels can do so to big ships.The scientific name is a combination of...

), big-eyed bugs (Geocoris

Geocoris

Geocoris is a genus of insects in the family Lygaeidae . Commonly known as the big-eyed bug, Geocoris is a beneficial predator often confused with the true chinch bug, which is a pest.Big-eyed bugs are true bugs in the order Hemiptera...

species), and predatory thrips

Thrips

Thrips are tiny, slender insects with fringed wings . Other common names for thrips include thunderflies, thunderbugs, storm flies, thunderblights, and corn lice...

 can be important natural enemies.

Many mites in the family Phytoseiidae

Phytoseiidae

Phytoseiidae is a family of mites which feed on thrips and other mite species. They are often used as a biological control agent for managing mite pests.-Subfamilies:* Amblyseiinae Muma, 1961* Phytoseiinae Berlese, 1916* Typhlodrominae Scheuten, 1857...

 are predators of spider mites. In addition to those that occur naturally, some of these are produced in commercial insectaries for release as biological controls. Among those most commonly sold via mail order are Galendromus occidentalis, Phytoseiulus persimilis, Mesoseiulus longipes, Amblyseius fallicus, and Neoseiulus californicus. Predatory mites eat adult mites, their eggs, and all developmental stages between. Predatory mites can consume as many as 5 adult spider mites per day, or 20 eggs per day.