Spider mite

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Spider mites
Tetranychus urticae with silk threads.jpg
Tetranychus urticae
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Subclass: Acari
Order: Trombidiformes
Superfamily: Tetranychoidea
Family: Tetranychidae
Donnadieu, 1875
Subfamilies & tribes

Bryobinae Berlese

  • Bryobini Reck
  • Hystrichonychini Pritchard & Baker
  • Petrobiini Reck

Tetranychinae Berlese

  • Tenuipalpoidini Pritchard & Baker
  • Tetranychini Reck

Spider mites are members of the Acari (mite) family Tetranychidae, which includes about 1,200 species.[1] They generally live on the undersides of leaves of plants, where they may spin protective silk webs, and they can cause damage by puncturing the plant cells to feed.[2] Spider mites are known to feed on several hundred species of plants.

Description[edit]

Spider mites are less than 1 millimetre (0.04 in) in size and vary in color. They lay small, spherical, initially transparent eggs and many species spin silk webbing to help protect the colony from predators; they get the "spider" part of their common name from this webbing.[2]

Life cycle[edit]

Spider mites on a lemon plant

Hot, dry conditions are often associated with population build-up of spider mites. Under optimal conditions (approximately 80 °F or 27 °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. This accelerated reproductive rate allows spider mite populations to adapt quickly to resist pesticides, so chemical control methods can become somewhat ineffectual when the same pesticide is used over a prolonged period.[3]

Spider mites, like hymenopterans and some homopterous insects, are arrhenotochous: females are diploid and males are haploid.[4] 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[edit]

The best known member of the group Tetranychus urticae, which has a cosmopolitan distribution,[5] and attacks a wide range of plants, including peppers, tomatoes, potatoes, beans, corn, cannabis, and strawberries.[3] Other species which can be important pests of commercial plants include Panonychus ulmi (fruit tree red spider mite) and Panonychus citri (citrus red mite).

The family is divided into the following subfamilies, tribes and genera:[6]

Bryobinae Berlese
  • Bryobini Reck
  • Hystrichonychini Pritchard & Baker
  • Petrobiini Reck
Tetranychinae Berlese
  • Eurytetranychini Reck
  • Tenuipalpoidini Pritchard & Baker
  • Tetranychini Reck

Countermeasures[edit]

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

Predatory mites eat adult mites, their eggs, and all developmental stages between.[3] Predatory mites can consume as many as 5 adult spider mites per day, or 20 eggs per day.[3]

In some cases, the application of Harpin Alpha Beta protein may help in the treatment and prevention of infestation by stimulating the plant's natural defenses, restoring sap sugar levels and encouraging replacement of damaged tissues.[7][8] Since spider mites down-regulate the immune response of a plant,[9] there is evidence that the application of Harpin may speed recovery and help prevent secondary infection and infestation.[10]

See also[edit]

References[edit]

  1. ^ H. R. Bolland, Jean Gutierrez & Carlos H. W. Flechtmann (1997). "Introduction". World Catalogue of the Spider Mite Family (Acari: Tetranychidae). Brill Publishers. pp. 1–3. ISBN 978-90-04-11087-8. 
  2. ^ a b Yutaka Saito (2009). "Plant mites". Plant Mites and Sociality: Diversity and Evolution. Springer. pp. 5–38. doi:10.1007/978-4-431-99456-5_2. ISBN 978-4-431-99455-8. 
  3. ^ a b c d Thomas R. Fasulo & H. A. Denmark (December 2009). "Twospotted spider mite". Featured Creatures. University of Florida / Institute of Food and Agricultural Sciences. Retrieved May 20, 2011. 
  4. ^ Graham Bell (1982). "Parthenogenesis and vegetative reproduction in multicellular animals". The Masterpiece of Nature: the Evolution and Genetics of Sexuality. Croom Helm applied biology series. Cambridge University Press. pp. 160–331. ISBN 978-0-85664-753-6. 
  5. ^ D. A. Raworth, D. R. Gillespie, M. Roy & H. M. A. Thistlewood (2002). "Tetranychus urticae Koch, twospotted spider mite (Acari: Tetranychidae)". In Peter G. Mason & John Theodore Huber. Biological Control Programmes in Canada, 1981–2000. CAB International. pp. 259–265. ISBN 978-0-85199-527-4. 
  6. ^ H. R. Bolland, Jean Gutierrez & Carlos H. W. Flechtmann (1997). "Key to the genera of the world". World Catalogue of the Spider Mite Family (Acari: Tetranychidae). Brill Publishers. pp. 5–11. ISBN 978-90-04-11087-8. 
  7. ^ http://www.owlyn.com/spider-mites-laying-the-final-blow.html
  8. ^ http://www.halo-harpin.com/en/studies_2.html
  9. ^ https://library.villanova.edu/Find/Summon/Record?id=FETCH-LOGICAL-p1143-f77a499cf1888c540b85d352360958fa56817266436b7e9e4a8a896be1bf32b11
  10. ^ http://www.researchgate.net/publication/229118471_The_effect_of_harpin_protein_on_plant_growth_parameters_leaf_chlorophyll_leaf_colour_and_percentage_rotten_fruit_of_pepper_plants_inoculated_with_Botrytis_cinerea

External links[edit]