Editing Parasitoid (section)

=== In biological pest control ===
{{Main|Biological pest control}}
[[File:Encarsia formosa, an endoparasitic wasp, is used for whitefly control.jpg|thumb|''[[Encarsia formosa]]'', an endoparasitic [[Aphelinidae|aphelinid]] wasp, bred commercially to control whitefly in [[greenhouse]]s]]

Parasitoids are among the most widely used biological control agents. Classic [[biological pest control]] using natural enemies of pests (parasitoids or predators) is extremely cost effective, the cost/benefit ratio for classic control being 1:250, but the technique is more variable in its effects than pesticides; it reduces rather than eliminates pests. The cost/benefit ratio for screening natural enemies is similarly far higher than for screening chemicals: 1:30 against 1:5 respectively, since the search for suitable natural enemies can be guided accurately with ecological knowledge. Natural enemies are more difficult to produce and to distribute than chemicals, as they have a shelf life of weeks at most; and they face a commercial obstacle, namely that they cannot be patented.<ref name="Bale2008">{{cite journal | last1=Bale | first1=J.S | last2=van Lenteren | first2=J.C | last3=Bigler | first3=F | title=Biological control and sustainable food production | journal=Philosophical Transactions of the Royal Society B: Biological Sciences | publisher=The Royal Society | volume=363 | issue=1492 | date=February 2008 | doi=10.1098/rstb.2007.2182 | pmid=17827110 | pages=761–776| pmc=2610108 }}</ref><ref>{{cite web |last1=Legner |first1=Erich F.|title=Economic Gains & Analysis Of Successes In Biological Pest Control |url=http://www.faculty.ucr.edu/~legneref/biotact/bc-5.htm |publisher=University of California, Riverside |access-date=13 February 2018 |archive-url=https://web.archive.org/web/20080623113302/http://www.faculty.ucr.edu/~legneref/biotact/bc-5.htm |archive-date=23 June 2008 |url-status=live}}</ref>

From the point of view of the farmer or horticulturalist, the most important groups are the [[Ichneumon wasp|ichneumonid wasps]], which prey mainly on [[caterpillar]]s of [[butterflies]] and [[moths]]; [[braconid wasp]]s, which attack caterpillars and a wide range of other insects including [[aphid|greenfly]]; [[chalcid wasp|chalcidoid wasps]], which parasitise eggs and larvae of greenfly, [[whitefly]], [[cabbage caterpillar]]s, and [[scale insect]]s; and [[Tachinidae|tachinid flies]], which parasitise a wide range of insects including caterpillars, adult and larval [[beetle]]s, and [[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 |archive-date=27 August 2016 |archive-url=https://web.archive.org/web/20160827072031/https://extension.umd.edu/hgic/insects/parasitoid-wasps-hymenoptera |url-status=dead }}</ref> Commercially, there are two types of rearing systems: short-term seasonal daily output with high production of parasitoids per day, and long-term year-round low daily output with a range in production of 4–1000 million female parasitoids per week, to meet demand for suitable biological control agents for different crops.<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><ref>{{cite book |author1=Wajnberg, E. |author2=Hassan, S.A. |title=Biological Control with Egg Parasitoids |publisher=CABI Publishing |year=1994}}</ref>{{-}}