Spider mites are members of the Tetranychidae family, which includes about 1,200 species. They are part of the subclass
Acari
Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evid ...
(mites). Spider mites generally live on the undersides of
leaves
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...
of
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae excl ...
s, where they may spin protective silk
webs, and they can cause damage by puncturing the plant
cells
Cell most often refers to:
* Cell (biology), the functional basic unit of life
Cell may also refer to:
Locations
* Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
to feed.
Spider mites are known to feed on several hundred
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
of plants.
Description
Spider mites are less than in size and vary in color. They lay small, spherical, initially transparent
eggs and many species spin silk webbing to help protect the
colony
In modern parlance, a colony is a territory subject to a form of foreign rule. Though dominated by the foreign colonizers, colonies remain separate from the administration of the original country of the colonizers, the '' metropolitan state' ...
from
predators; 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 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.
Spider mites, like
hymenoptera
Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic.
Females typic ...
ns and some
scale insect
Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than th ...
s, are
haplodiploid and therefore
arrhenotochous: females are
diploid
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectiv ...
and males are
haploid
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respective ...
. 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
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respective ...
males.
To spread to new locations, they make use of
ballooning for aerial dispersal.
Genera
The best known member of the group is ''
Tetranychus urticae'', which has a
cosmopolitan distribution
In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The extr ...
,
and attacks a wide range of plants, including
peppers,
tomato
The tomato is the edible berry of the plant ''Solanum lycopersicum'', commonly known as the tomato plant. The species originated in western South America, Mexico, and Central America. The Mexican Nahuatl word gave rise to the Spanish word ...
es,
potato
The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae.
Wild potato species can be found from the southern Uni ...
es,
bean
A bean is the seed of several plants in the family Fabaceae, which are used as vegetables for human or animal food. They can be cooked in many different ways, including boiling, frying, and baking, and are used in many traditional dishes th ...
s,
corn
Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The ...
,
cannabis
''Cannabis'' () is a genus of flowering plants in the family Cannabaceae. The number of species within the genus is disputed. Three species may be recognized: '' Cannabis sativa'', '' C. indica'', and '' C. ruderalis''. Alternative ...
, and
strawberries
The garden strawberry (or simply strawberry; ''Fragaria × ananassa'') is a widely grown hybrid species of the genus '' Fragaria'', collectively known as the strawberries, which are cultivated worldwide for their fruit. The fruit is widely ap ...
.
Other species which can be important pests of commercial plants include ''
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 (21 days at ) and produces many broods in a year, all of which contribu ...
'' (fruit tree red spider mite) and ''
Panonychus citri'' (citrus red mite).
The family is divided into these
subfamilies,
tribes
The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to confli ...
and
genera
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
:
;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''
Dufour
:*''
Amphitetranychus''
Oudemans
Countermeasures
Neem oil
Neem oil
Neem oil, also known as margosa oil, is a vegetable oil pressed from the fruits and seeds of the neem (''Azadirachta indica''), a tree which is indigenous to the Indian subcontinent and has been introduced to many other areas in the tropics. It ...
may provide control, when combined with a suitable surfactant and diluted with water. As with chemical control, repeated applications are required.
Predatory mites
Predatory mites of the
Phytoseiidae
The Phytoseiidae are 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. Because of their usefulness as biological control agents, interest in Phytoseiidae has ...
family, including ''
Phytoseiulus persimilis
''Phytoseiulus'' is a genus of mites in the Phytoseiidae family. A predatory mite, this is the mite predator most frequently used to control two-spotted spider mites in greenhouses and outdoor crops grown in mild environments. This mite was ac ...
'', 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.
Insecticidal soap
Insecticidal soap spray is effective against spider mites. It is commercially available or can be made of certain types of household soap. However, since it will also kill predatory mites, its use is not recommended if the latter are present.
Harpin Alpha Beta
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. This affects the spider mites' ability to down-regulate the immune response of a plant.
Acaricides
Acaricides are applied to crops to control spider mites. They can be either
systemic
Systemic fundamental to a predominant social, economic, or political practice. This refers to:
In medicine
In medicine, ''systemic'' means affecting the whole body, or at least multiple organ systems. It is in contrast with ''topical'' or ''loc ...
or non-systemic in nature and can be persistent by providing residual activity for over a month. Drawbacks include high potential for development of
resistance in mite populations, as has been observed in previous generations of miticides, and toxicity of some miticides towards fish. Thus proper selection, precautions and application are required to minimize risks.
Environmental conditions
Temporarily modifying environmental conditions has proven an effective method for insect pest control including spider mites. Generally dramatically decreased oxygen and increased carbon dioxide concentrations at elevated temperatures can lead to mortality at all developmental stages. However mild CO
2 enrichment has been shown to in fact increase mite reproduction. One study determined a concentration of 0.4% O
2 and 20% CO
2 gave a
LT99 (time to 99% mortality) of 113h at 20 °C and 15.5h at 40 °C. Another study reported 100% mortality of various stages of the two spotted spidermite using 60% CO
2 and 20% O
2 at 30 °C for 16h.
Advantages would include decreased ability for resistance development compared to miticides and potential ease of application while drawbacks might include sensitivity of the plant to the conditions, feasibility of application, and human safety.
See also
*
Pests and diseases of roses
References
External links
*
*
*
*
{{Authority control
Trombidiformes
fi:Vihannespunkki