Editing Scale insect (section)

==Significance==

===As pests===

Many scale species are serious crop [[pest (animal)|pest]]s and are particularly problematic for their ability to evade [[Pest quarantine|quarantine]] measures.<ref>{{Cite journal |last1=Sethusa |first1=M.T. |last2=Millar |first2=I.M. |last3=Yessoufou |first3=K. |last4=Jacobs |first4=A. |last5=Bank |first5=M. van der |last6=Bank |first6=H. van der |date=2014 |title=DNA Barcode Efficacy for the Identification of Economically Important Scale Insects (Hemiptera: Coccoidea) in South Africa |url=http://www.bioone.org/doi/abs/10.4001/003.022.0218 |journal=African Entomology |language=en |volume=22 |issue=2 |pages=257–266 |doi=10.4001/003.022.0218 |s2cid=84171305 |issn=1021-3589|url-access=subscription }}</ref><ref name="ISU">{{cite web |title=Scale Insects |url=https://hortnews.extension.iastate.edu/scale-insects |publisher=Iowa State University |access-date=14 January 2020}}</ref> In 1990, they caused around $5&nbsp;billion of damage to crops in the United States.<ref name="Piper2011">{{cite book |last=Piper |first=Ross |title=Pests: A Guide to the World's Most Maligned, Yet Misunderstood Creatures |url=https://books.google.com/books?id=wRDIOhoQR68C&pg=PA149 |year=2011 |publisher=ABC-CLIO |isbn=978-0-313-38426-4 |page=149}}</ref>
The waxy covering of many species of scale protects their adults effectively from contact [[insecticide]]s, which are only effective against the first-instar [[Nymph (biology)|nymph]] stage known as the ''crawler''. However, scales can often be controlled using [[horticultural oil]]s that [[suffocation|suffocate]] them, systemic pesticides that poison the sap of the host plants, or by [[biological control]] agents such as tiny [[parasitoid]] wasps and ladybirds. [[Insecticidal soap]] may also be used against scales.<ref>{{cite web |title=Scale insects |url=https://www.gardenersworld.com/how-to/solve-problems/scale-insects/ |website=[[Gardeners' World]] |access-date=16 January 2020}}</ref>

One species, the cottony cushion scale, is a serious commercial pest on 65 families of woody plants, including ''[[Citrus]]'' fruits. It has spread worldwide from Australia.<ref>[http://scalenet.info/catalogue/Icerya%20purchasi/ ScaleNet]</ref><ref>{{cite book |last=Nair |first=K. S. S. |date=2007 |title=Tropical Forest Insect Pests: Ecology, Impact, and Management |url=https://books.google.com/books?id=QvOPufXCJq0C&pg=PA221 |publisher=Cambridge University Press |isbn=9781139464857 |page=221}}</ref>

<gallery class="center" mode="nolines" widths="200px" heights="200px">
File:Icerya purchasi feeding on Citrus.jpg|Adult female [[cottony cushion scale]] (''Icerya purchasi'') with young crawlers. The species is a major commercial pest of crops such as ''Citrus'' fruits.
File:Anagyrus lopezi.jpg|The tiny [[parasitic wasp]] ''[[Anagyrus|Anagyrus lopezi]]'', a highly effective biological control of the [[cassava]] mealybug
</gallery>

===As biological controls===

At the same time, some kinds of scale insects are themselves useful as biological control agents for pest plants, such as various species of [[Dactylopius|cochineal insects]] that attack [[invasive species]] of [[Opuntia|prickly pear]], which spread widely especially in [[Prickly pears in Australia|Australia]] and Africa.<ref name=Ramirez>{{cite journal|last=Ramírez-Puebla |first=S. T. |year=2010 |url=http://www.bashanfoundation.org/martinez/martinezdactylopius.pdf |title=Molecular phylogeny of the genus ''Dactylopius'' (Hemiptera: Dactylopiidae) and identification of the symbiotic bacteria |archive-url=https://web.archive.org/web/20150923182527/http://www.bashanfoundation.org/martinez/martinezdactylopius.pdf |archive-date=2015-09-23 |journal=Environmental Entomology |volume=39 |issue=4 |pages=1178–83 |doi=10.1603/EN10037 |pmid=22127169 |s2cid=5816903 |doi-access=free }}</ref><ref name="cabi">{{cite web |title=''Opuntia ficus-indica'' (prickly pear) |url=https://www.cabi.org/isc/datasheet/37714 |publisher=CABI |date=3 January 2018}}</ref>

===Products===

Some types of scale insect are economically valuable for the substances they can yield under proper husbandry. Some, such as the [[cochineal]], [[Kermes (insect)|kermes]], [[lac scale|lac]], [[Armenian cochineal]], and [[Polish cochineal]], have been used to produce red dyes for coloring foods and dyeing fabrics.<ref>{{cite web |url=http://www.fao.org/docrep/v8879e/v8879e09.htm |title=Cochineal and Carmine |work=Major colourants and dyestuffs, mainly produced in horticultural systems |publisher=FAO |access-date=June 16, 2015}}</ref><ref>{{cite web |url=https://www.fda.gov/ForIndustry/ColorAdditives/GuidanceComplianceRegulatoryInformation/ucm153038.htm |archive-url=https://web.archive.org/web/20090606162207/http://www.fda.gov/ForIndustry/ColorAdditives/GuidanceComplianceRegulatoryInformation/ucm153038.htm |url-status=dead |archive-date=June 6, 2009 |title=Guidance for Industry: Cochineal Extract and Carmine |publisher=FDA |access-date=6 July 2016}}</ref><ref name="Munro214">{{cite book |last=Munro |first=John H. |chapter=4: Medieval Woollens: Textiles, Technology, and Organisation c. 800–1500|editor=Jenkins, David |year=2003 |title=The Cambridge History of Western Textiles |volume=I |publisher=Cambridge University Press |isbn=0-521-34107-8 |oclc=48475172 |pages=214–215 |chapter-url=https://archive.org/details/cambridgehistory0000unse_l9b6/page/214/mode/1up?view=theater&q=%22Kermes+%28Kermococcus%29+vermilio%22 }}</ref> Both the colour name "[[crimson]]" and the generic name ''Kermes'' are from Italian ''carmesi'' or ''cremesi'' for the dye used for Italian silk textiles, in turn from the Persian<ref>{{cite web |last1=ویکی |first1=پارسی |title=معنی قرمز {{!}} لغت نامه دهخدا |url=https://www.parsi.wiki/fa/wiki/345624/%D9%82%D8%B1%D9%85%D8%B2 |website=پارسی ویکی |access-date=3 April 2021 |language=fa}}</ref> ''qirmizī'' (قرمز), meaning both the colour and the insect.<ref>{{cite web |title=Crimson (n.) |url=https://www.etymonline.com/word/crimson |publisher=Etymology Online |access-date=17 January 2020}}</ref> The colour name "[[Scarlet (color)|scarlet]]" is similarly derived from Arabic ''siklāt'', denoting extremely expensive luxury silks dyed red using kermes.<ref>{{Cite encyclopedia |last=Munro |first=John |year=2012 | chapter=Scarlet |editor=Gale Owen-Crocker |editor2=Elizabeth Coatsworth |editor3=Maria Hayward |title=Encyclopedia of Medieval Dress and Textiles |publisher=Brill | doi=10.1163/2213-2139_emdt_COM_550 |isbn=978-9004124356 }}</ref>

Some waxy scale species in the genera ''[[Ceroplastes]]'' and ''[[Ericerus]]'' produce materials such as [[Chinese wax]],<ref>{{cite book|author=Zhang, Xiaoming |title=Chinese Furniture|url=https://books.google.com/books?id=uT-2qaTOYEsC&pg=PA58 |year=2011|publisher=Cambridge University Press|isbn=978-0-521-18646-9 |page=58}}</ref> and several genera of [[lac scale]]s produce [[shellac]].<ref>{{cite news |title=How Shellac Is Manufactured |url=http://nla.gov.au/nla.news-article55073762 |publisher=The Mail (Adelaide, SA : 1912 – 1954) |date=18 Dec 1937}}</ref>

<gallery class="center" mode="nolines" widths="200px" heights="200px">
File:Indian collecting cochineal.jpg|Collecting scale insects from a prickly pear for a [[dyestuff]], cochineal, 1777
File:Weltliche Schatzkammer Wienc.jpg|Coronation cloak of King [[Roger II of Sicily]], 1133. Silk [[Scarlet (cloth)|scarlet cloth]] dyed with [[Kermes (dye)|kermes]], made from female ''Kermes'' scales
File:Shellac varities.png|Some varieties of shellac
File:02-Indian-Insect-Life - Harold Maxwell-Lefroy - Kerria-Lacca.jpg|''[[Kerria lacca]]'' and its shellac tubes
</gallery>