Editing Biological pest control (section)

===Parasitoids===
{{main|Parasitoid}}

Parasitoids lay their eggs on or in the body of an insect host, which is then used as a food for developing larvae. The host is ultimately killed. Most insect [[parasitoid]]s are [[Parasitoid wasp|wasps]] or [[Fly|flies]], and many have a very narrow host range. The most important groups are the [[Ichneumonidae|ichneumonid wasps]], which mainly use [[caterpillar]]s as hosts; [[Braconidae|braconid wasps]], which attack caterpillars and a wide range of other insects including aphids; [[chalcid wasp|chalcidoid wasps]], which parasitize eggs and larvae of many insect species; and [[Tachinidae|tachinid flies]], which parasitize a wide range of insects including caterpillars, [[beetle]] adults and larvae, and [[Hemiptera|true bugs]].<ref>{{cite web|title=Parasitoid Wasps (Hymenoptera) |url=https://extension.umd.edu/hgic/insects/parasitoid-wasps-hymenoptera |publisher=University of Maryland |access-date=6 June 2016 |url-status=live |archive-url=https://web.archive.org/web/20160827072031/https://extension.umd.edu/hgic/insects/parasitoid-wasps-hymenoptera |archive-date=27 August 2016}}</ref> Parasitoids are most effective at reducing pest populations when their host organisms have limited [[refuge (ecology)|refuges]] to hide from them.<ref name="HawkinsThomas1993">{{cite journal |last1=Hawkins |first1=B. A. |last2=Thomas |first2=M. B. |last3=Hochberg |first3=M. E. |title=Refuge Theory and Biological Control |journal=Science |volume=262 |issue=5138 |year=1993 |pages=1429–1432 |doi=10.1126/science.262.5138.1429 |pmid=17736826|bibcode=1993Sci...262.1429H |s2cid=45268030 }}</ref>

[[File:Encarsia formosa, an endoparasitic wasp, is used for whitefly control.jpg|thumb|''[[Encarsia formosa]]'', widely used in [[greenhouse]] horticulture, was one of the first biological control agents developed.]]
[[File:Waspcycle.png|thumb|right|450px|Life cycles of greenhouse whitefly and its parasitoid wasp ''[[Encarsia formosa]]'']]

Parasitoids are among the most widely used biological control agents. Commercially, there are two types of rearing systems: short-term daily output with high production of parasitoids per day, and long-term, low daily output systems.<ref name=smith>{{cite journal |author=Smith, S.M. |date=1996 |title=Biological control with Trichogramma: advances, successes, and potential of their use |journal=Annual Review of Entomology |volume=41 |pages=375–406 |pmid=15012334 |doi=10.1146/annurev.en.41.010196.002111}}</ref> In most instances, production will need to be matched with the appropriate release dates when susceptible host species at a suitable phase of development will be available.<ref>{{cite journal |author1= Knoll, Valery |author2=Ellenbroek, Thomas |author3=Romeis, Jörg |author4=Collatz, Jana  |year=2017 |title=Seasonal and regional presence of hymenopteran parasitoids of ''Drosophila'' in Switzerland and their ability to parasitize the invasive ''Drosophila suzukii'' |journal=Scientific Reports |volume=7 |issue=40697 |pages=40697 |doi=10.1038/srep40697 |pmid=28098183 |pmc=5241644 |bibcode=2017NatSR...740697K }}</ref> Larger production facilities produce on a yearlong basis, whereas some facilities produce only seasonally. Rearing facilities are usually a significant distance from where the agents are to be used in the field, and transporting the parasitoids from the point of production to the point of use can pose problems.<ref>{{cite book|author1=Sithanantham, S. |author2=Ballal, Chandish R. |author3=Jalali, S.K. |author4=Bakthavatsalam, N. |title=Biological Control of Insect Pests Using Egg Parasitoids |url=https://books.google.com/books?id=cCO4BAAAQBAJ&pg=PA246 |year=2013 |publisher=Springer |isbn=978-81-322-1181-5 |page=246 |url-status=live |archive-url=https://web.archive.org/web/20170410133425/https://books.google.com/books?id=cCO4BAAAQBAJ&pg=PA246 |archive-date=10 April 2017}}</ref> Shipping conditions can be too hot, and even vibrations from planes or trucks can adversely affect parasitoids.<ref name=smith/>

''[[Encarsia formosa]]'' is a small parasitoid wasp attacking [[whitefly|whiteflies]], sap-feeding insects which can cause wilting and [[Sooty mold|black sooty moulds]] in glasshouse vegetable and ornamental crops. It is most effective when dealing with low level infestations, giving protection over a long period of time. The wasp lays its eggs in young whitefly 'scales', turning them black as the parasite larvae pupate.<ref name=Hoddle1998>{{cite journal |title=Biology and Use of the Whitefly Parasitoid Encarsia Formosa |author1=Hoddle, M. S. |author2=Van Driesche, R. G. |author3=Sanderson, J. P. |date=1998 |journal=Annual Review of Entomology |volume=43 |pages=645–669 |doi=10.1146/annurev.ento.43.1.645 |pmid=15012401 }}</ref> ''[[Gonatocerus ashmeadi]]'' ([[Hymenoptera]]: [[Mymaridae]]) has been introduced to control the [[glassy-winged sharpshooter]] ''Homalodisca vitripennis'' (Hemiptera: [[Cicadellidae]]) in [[French Polynesia]] and has successfully controlled ~95% of the pest density.<ref name=Hoddle2006>{{cite journal |author1=Hoddle M. S. |author2=Grandgirard J. |author3=Petit J. |author4=Roderick G. K. |author5=Davies N. | year=2006 | title=Glassy-winged sharpshooter Ko'ed – First round – in French Polynesia | journal=Biocontrol News and Information | volume=27 | issue=3 | pages=47N–62N}}</ref>

The [[Choristoneura fumiferana|eastern spruce budworm]] is an example of a destructive insect in [[fir]] and [[spruce]] forests. Birds are a natural form of biological control, but the ''Trichogramma minutum'', a species of parasitic wasp, has been investigated as an alternative to more controversial chemical controls.<ref name="smith2">{{Cite journal | doi=10.1111/j.1439-0418.1986.tb00830.x|title = Factors affecting inundative releases of ''Trichogramma'' minutum ''Ril''. Against the Spruce Budworm| journal=Journal of Applied Entomology| volume=101| issue=1–5| pages=29–39|year = 1986|last1 = Smith|first1 = S. M.| last2=Hubbes| first2=M.| last3=Carrow| first3=J. R.|s2cid = 84398725}}</ref>

There are a number of recent studies pursuing sustainable methods for controlling urban cockroaches using parasitic wasps.<ref>{{cite journal |last1=Bressan-Nascimento |first1=S. |last2=Oliveira |first2=D.M.P. |last3=Fox |first3=E.G.P. |title=Thermal requirements for the embryonic development of Periplaneta americana (L.) (Dictyoptera: Blattidae) with potential application in mass-rearing of egg parasitoids |journal=Biological Control |date=December 2008 |volume=47 |issue=3 |pages=268–272 |doi=10.1016/j.biocontrol.2008.09.001|bibcode=2008BiolC..47..268B }}</ref><ref>{{cite journal |last1=Paterson Fox |first1=Eduardo Gonçalves |last2=Bressan-Nascimento |first2=Suzete |last3=Eizemberg |first3=Roberto |title=Notes on the Biology and Behaviour of the Jewel Wasp, Ampulex compressa (Fabricius, 1781) (Hymenoptera; Ampulicidae), in the Laboratory, Including First Record of Gregarious Reproduction |journal=Entomological News |date=September 2009 |volume=120 |issue=4 |pages=430–437 |doi=10.3157/021.120.0412|s2cid=83564852 }}</ref> Since most cockroaches remain in the sewer system and sheltered areas which are inaccessible to insecticides, employing active-hunter wasps is a strategy to try and reduce their populations.