Editing Biological pest control (section)

===Predators===
[[File:Chrysopidae 3035.jpg|thumb|left|[[Predator]]y [[Chrysopidae|lacewings]] are available from biocontrol dealers.]]

Predators are mainly free-living species that directly consume a large number of [[prey]] during their whole lifetime. Given that many major crop pests are insects, many of the predators used in biological control are insectivorous species. [[Ladybugs|Lady beetles]], and in particular their larvae which are active between May and July in the northern hemisphere, are voracious predators of [[aphid]]s, and also consume [[mites]], [[scale insect]]s and small [[caterpillar]]s. The spotted lady beetle (''[[Coleomegilla maculata]]'') is also able to feed on the eggs and larvae of the [[Colorado potato beetle]] (''Leptinotarsa decemlineata'').<ref>{{cite book |author=Acorn, John |title=Ladybugs of Alberta: Finding the Spots and Connecting the Dots |url=https://archive.org/details/ladybugsofalbert00acor |url-access=registration |year=2007 |publisher=University of Alberta |isbn=978-0-88864-381-0 |page=[https://archive.org/details/ladybugsofalbert00acor/page/15 15]}}</ref>

The larvae of many [[hoverfly]] species principally feed upon [[aphid]]s, one larva devouring up to 400 in its lifetime. Their effectiveness in commercial crops has not been studied.<ref>{{cite web |title=Know Your Friends. Hover Flies |url=http://www.entomology.wisc.edu/mbcn/kyf211.html |publisher=University of Wisconsin |access-date=7 June 2016 |url-status=dead |archive-url=https://web.archive.org/web/20160604163106/http://www.entomology.wisc.edu/mbcn/kyf211.html |archive-date=4 June 2016 }}</ref>

The running crab spider ''[[Philodromus cespitum]]'' also prey heavily on aphids, and act as a biological control agent in European fruit orchards.<ref>Michalko, Radek; Dvoryankina, Viktoriya (1 June 2019). "Intraspecific phenotypic variation in functional traits of a generalist predator in an agricultural landscape". ''Agriculture, Ecosystems & Environment''. '''278''': 35–42. [[Doi (identifier)|doi]]:10.1016/j.agee.2019.03.018.</ref>

[[File:Organic-agriculture biocontrol-cotton polistes-wasp3.png|thumb|[[Predator]]y ''[[Paper wasp|Polistes]]'' [[Vespid|wasp]] searching for bollworms or other [[caterpillar]]s on a cotton plant]]

Several species of [[entomopathogenic nematode]] are important predators of insect and other invertebrate pests.<ref>{{cite book |author=Kaya, Harry K. |chapter=An Overview of Insect-Parasitic and Entomopathogenic Nematodes |editor=Bedding, R.A. |title=Nematodes and the Biological Control of Insect Pests |publisher=CSIRO Publishing |year=1993 |isbn=978-0-643-10591-1 |chapter-url=https://books.google.com/books?id=drhdg7UmNnAC&pg=PT8 |pages=8–12 |display-authors=etal |url-status=live |archive-url=https://web.archive.org/web/20160512141401/https://books.google.com/books?id=drhdg7UmNnAC&pg=PT8 |archive-date=12 May 2016}}</ref><ref name=Capinera1992>{{Cite journal |last1=Capinera |first1=John L. |last2=Epsky |first2=Nancy D. |date=1992-01-01 |title=Potential for Biological Control of Soil Insects in the Caribbean Basin Using Entomopathogenic Nematodes |journal=The Florida Entomologist |volume=75 |issue=4 |pages=525–532 |jstor=3496134 |doi=10.2307/3496134}}</ref> Entomopathogenic nematodes form a stress–resistant stage known as the infective juvenile. These spread in the soil and infect suitable insect hosts. Upon entering the insect they move to the [[hemolymph]] where they recover from their stagnated state of development and release their [[Photorhabdus|bacterial]] [[Symbiosis|symbionts]]. The bacterial symbionts reproduce and release toxins, which then kill the host insect.<ref name=Capinera1992/><ref name=Campos2015>{{cite book |title=Nematode Pathogenesis of insects and other pests |date=2015 |publisher=Springer |isbn=978-3-319-18266-7 |edition=1 |pages=4–6, 31–32 |last=Campos |first=Herrera R. |editor1-first=Raquel |editor1-last=Campos-Herrera |doi=10.1007/978-3-319-18266-7|hdl=11586/145351 |s2cid=27605492 }}</ref> ''[[Phasmarhabditis hermaphrodita]]'' is a microscopic [[nematode]] that kills slugs. Its complex life cycle includes a free-living, infective stage in the soil where it becomes associated with a pathogenic bacteria such as ''[[Moraxella osloensis]]''. The nematode enters the slug through the posterior mantle region, thereafter feeding and reproducing inside, but it is the bacteria that kill the slug. The nematode is available commercially in Europe and is applied by watering onto moist soil.<ref>{{cite web |url=http://www.biocontrol.entomology.cornell.edu/pathogens/phasmarhabditis.php |title=Biological control: ''Phasmarhabditis hermaphrodita'' |publisher=Cornell University |access-date=15 June 2016 |url-status=dead |archive-url=https://web.archive.org/web/20160618025012/http://www.biocontrol.entomology.cornell.edu/pathogens/phasmarhabditis.php |archive-date=18 June 2016 }}</ref> Entomopathogenic nematodes have a limited [[shelf life]] because of their limited resistance to high temperature and dry conditions.<ref name=Campos2015/> The type of soil they are applied to may also limit their effectiveness.<ref name=Capinera1992/>

Species used to control spider mites include the predatory mites ''[[Phytoseiulus persimilis]]'',<ref>{{cite web |title=Glasshouse red spider mite |url=https://www.rhs.org.uk/advice/profile?PID=190 |publisher=[[Royal Horticultural Society]] |access-date=7 June 2016 |url-status=live |archive-url=https://web.archive.org/web/20160614161933/https://www.rhs.org.uk/advice/profile?PID=190 |archive-date=14 June 2016 }}</ref> ''[[Neoseilus]] [[Neoseilus californicus|californicus]],''<!--aka Amblyseius--><ref name=UConnMites/> and ''[[Amblyseius]] [[Amblyseius cucumeris|cucumeris]]'', the predatory midge ''[[Feltiella acarisuga]]'',<ref name=UConnMites>{{cite web |title=Biological Control of Two- Spotted Spider Mites |url=http://ipm.uconn.edu/documents/raw2/html/664.php?aid=664 |publisher=University of Connecticut |access-date=7 June 2016 |url-status=live |archive-url=https://web.archive.org/web/20160807023211/http://ipm.uconn.edu/documents/raw2/html/664.php?aid=664 |archive-date= 7 August 2016 }}</ref> and a ladybird ''[[Stethorus punctillum]]''.<ref name=UConnMites/> The bug ''[[Orius insidiosus]]'' has been successfully used against the [[Tetranychus urticae|two-spotted spider mite]] and the [[western flower thrips]] (''Frankliniella occidentalis'').<ref>{{cite book |author=Xuenong Xu |title=Combined Releases of Predators for Biological Control of Spider Mites ''Tetranychus urticae'' Koch and Western Flower Thrips ''Frankliniella occidentalis'' (Pergande) |url=https://books.google.com/books?id=y6DGyV7HmqAC&pg=PA37 |year=2004 |publisher=Cuvillier Verlag |isbn=978-3-86537-197-3 |page=37}}</ref>

Predators including ''Cactoblastis cactorum'' (mentioned above) can also be used to destroy invasive plant species. As another example, the [[Agonopterix alstroemeriana|poison hemlock moth]] (''Agonopterix alstroemeriana)'' can be used to control [[Conium maculatum|poison hemlock]] (''Conium maculatum''). During its larval stage, the moth strictly consumes its host plant, poison hemlock, and can exist at hundreds of larvae per individual host plant, destroying large swathes of the hemlock.<ref>{{Cite journal |last1=Castells |first1=Eva |last2=Berenbaum |first2=May R. |date=June 2006 |title=Laboratory Rearing of Agonopterix alstroemeriana, the Defoliating Poison Hemlock (Conium maculatum L.) Moth, and Effects of Piperidine Alkaloids on Preference and Performance |journal=Environmental Entomology |volume=35 |issue=3 |pages=607–615 |doi=10.1603/0046-225x-35.3.607|s2cid=45478867 |url=https://ddd.uab.cat/pub/artpub/2006/125702/2006_alstroemeriana_rearing.pdf }}</ref>

[[File:Aleiodes indiscretus wasp parasitizing gypsy moth caterpillar.jpg|thumb|The [[parasitoid wasp]] ''[[Aleiodes|Aleiodes indiscretus]]'' parasitizing a [[spongy moth]] caterpillar, a serious pest of forestry<ref>{{cite web | url=http://sfec.cfans.umn.edu/prod/groups/cfans/@pub/@cfans/@sfec/documents/article/cfans_article_380545.pdf | title=European Gypsy Moth (Lymantria dispar) | access-date=3 December 2017 | url-status=dead | archive-url=https://web.archive.org/web/20130517073305/http://sfec.cfans.umn.edu/prod/groups/cfans/@pub/@cfans/@sfec/documents/article/cfans_article_380545.pdf | archive-date=17 May 2013}}</ref>]]

For [[Rodent#As pests and disease vectors|rodent pests]], [[Farm cat|cat]]s are effective biological control when used in conjunction with reduction of [[Refuge (ecology)|"harborage"/hiding]] locations.<ref>{{cite journal |title=The Use of Food as a Buffer in a Predator-Prey System |first=David E. |last=Davis |date=20 November 1957 |journal=Journal of Mammalogy |volume=38 |issue=4 |pages=466–472 |doi=10.2307/1376399 |jstor=1376399 }}</ref><ref name="Lambert">{{cite thesis |type=PhD |last1=Lambert |first1=Mark |title=Control Of Norway Rats In The Agricultural Environment: Alternatives To Rodenticide Use |url=https://lra.le.ac.uk/bitstream/2381/27745/1/2003LambertMSPhD.pdf |publisher=University of Leicester |pages=85–103 |format=Thesis |date=September 2003 |access-date=2017-11-11 |archive-date=2017-11-11 |archive-url=https://web.archive.org/web/20171111151737/https://lra.le.ac.uk/bitstream/2381/27745/1/2003LambertMSPhD.pdf |url-status=dead }}</ref><ref name="Wodzicki">{{cite journal |title=Prospects for biological control of rodent populations |first=Kazimierz |last=Wodzicki |date=11 November 1973 |journal=Bulletin of the World Health Organization |volume=48 |issue=4 |pages=461–467 |pmid=4587482 |pmc=2481104}}</ref> While cats are effective at preventing rodent [[Irruptive growth|"population explosions"]], they are not effective for eliminating pre-existing severe infestations.<ref name="Wodzicki"/> [[Western barn owl|Barn owls]] are also sometimes used as biological rodent control.<ref name=Charter>{{cite web |url=http://www.owls.org/conservation/ewExternalFiles/barn_owls_in_israel.pdf |title=Using barn owls (''Tyto alba erlangeri'') for biological pest control in Israel |author=Charter, Motti |publisher=World Owl Trust |access-date=11 November 2017 |archive-url=https://web.archive.org/web/20171111095113/http://www.owls.org/conservation/ewExternalFiles/barn_owls_in_israel.pdf |archive-date=2017-11-11 |url-status=dead }}</ref> Although there are no quantitative studies of the effectiveness of barn owls for this purpose,<ref>{{cite journal |title=Are avian predators effective biological control agents for rodent pest management in agricultural systems? |first1=Lushka |last1=Labuschagne |first2=Lourens H. |last2=Swanepoel |first3=Peter J |last3=Taylor |first4=Steven R. |last4=Belmain |first5=Mark |last5=Keith |date=1 October 2016 |journal=Biological Control |volume=101 |issue=Supplement C |pages=94–102 |doi=10.1016/j.biocontrol.2016.07.003|bibcode=2016BiolC.101...94L |url=http://gala.gre.ac.uk/15648/23/15648%20BELMAIN_Avian_Predators_13-06-2016.pdf |hdl=10019.1/111721 |hdl-access=free }}</ref> they are known rodent predators that can be used in addition to or instead of cats;<ref>{{Cite book|url=https://books.google.com/books?id=4ddfAQAAQBAJ&pg=PA141 |title=Crop Protection in Medieval Agriculture: Studies in pre-modern organic agriculture |first=Jan C. |last=Zadoks | author-link=Jan Zadoks|date=16 October 2013 |publisher=Sidestone Press |access-date=11 November 2017 |via=Google Books|isbn=9789088901874 }}</ref><ref>{{cite web |url=https://attra.ncat.org/how_can_i_control_rodents_organically/ |title=How can I control rodents organically? |publisher=ATTRA - National Sustainable Agriculture Information Service |access-date=11 November 2017 |archive-date=17 October 2021 |archive-url=https://web.archive.org/web/20211017132940/https://attra.ncat.org/how_can_i_control_rodents_organically/ |url-status=dead }}</ref> they can be encouraged into an area with nest boxes.<ref>{{cite journal |title=Agricultural land use, barn owl diet, and vertebrate pest control implications |first1=Sara M. |last1=Kross |first2=Ryan P. |last2=Bourbour |first3=Breanna L. |last3=Martinico |date=1 May 2016 |journal=Agriculture, Ecosystems & Environment |volume=223 |issue=Supplement C |pages=167–174 |doi=10.1016/j.agee.2016.03.002|bibcode=2016AgEE..223..167K }}</ref><ref>{{cite web |url=https://www.barnowltrust.org.uk/barn-owl-facts/barn-owl-home-range/ |title=Barn Owl home range |publisher=The Barn Owl Trust |access-date=11 November 2017}}</ref>

In Honduras, where the mosquito ''[[Aedes aegypti]]'' was transmitting [[dengue fever]] and other infectious diseases, biological control was attempted by a community action plan; [[copepod]]s, baby [[turtle]]s, and juvenile [[tilapia]] were added to the wells and tanks where the mosquito breeds and the mosquito larvae were eliminated.<ref>{{cite web |url=http://ecotippingpoints.org/our-stories/indepth/honduras-community-eradication-aedes-aegypti-dengue-zika.html |title=The Monte Verde Story (Honduras): Community Eradication of Aedes aegypti (the mosquito responsible for Zika, dengue fever, and chikungunya) |author= Marten, Gerry; Caballero, Xenia; Romero, Hilda; Larios, Arnulfo |date=1 January 2019 |publisher=The EcoTipping Point Project  |access-date=30 January 2020}}</ref>

Even amongst arthropods usually thought of as obligate [[predator]]s of animals (especially other arthropods), [[flower|floral]] food sources ([[nectar]] and to a lesser degree [[pollen]]) are often useful adjunct sources.<ref name="He-et-al-2021" /> It had been noticed in one study<ref name="He-Sigsgaard-2019" /> that adult ''[[Adalia bipunctata]]'' (predator and common biocontrol of ''[[Mediterranean flour moth|Ephestia kuehniella]]'') could survive on flowers but never completed its [[biological life cycle|life cycle]], so a meta-analysis<ref name="He-et-al-2021" /> was done to find such an overall trend in previously published data, if it existed. In some cases floral resources are outright necessary.<ref name="He-et-al-2021" /> Overall, floral resources (and an imitation, i.e. sugar water) increase [[longevity]] and [[fecundity]], meaning even predatory population numbers can depend on non-prey food abundance.<ref name="He-et-al-2021" /> Thus biocontrol population maintenance – and success – may depend on nearby flowers.<ref name="He-et-al-2021" />