Delia (fly)

{{Short description|Genus of flies}} {{Automatic taxobox | image = Delia.radicum.jpg | image_caption = ''Delia radicum'' | taxon = Delia | authority = Robineau-Desvoidy, 1830 | display_parents = 2 | type_species = ''Delia floricola'' | type_species_authority = Robineau-Desvoidy, 1830 | synonyms = *''Atrichodelia'' Karl, 1943 *''Bisetaria'' Karl, 1943 *''Chaetodelia'' Karl, 1943 *''Chortophilina'' Karl, 1928<ref name="Karl1928">{{cite book|last1=Karl|first1=O.|title=Zweiflugler oder Diptera. III. Muscidae. In Dahl, F. (ed.), Tierwelt Deutschlands, Teil 13|date=1928|publisher=G. Fischer|location=Jena|pages=1–232}}</ref> *''Cimbotoma'' Lioy, 1864 *''Crinura'' Schnabl & Dziedzicki, 1911 *''Eroischia'' Lioy, 1864 *''Flavena'' Karl, 1928<ref name="Karl1928"/> *''Gastrolepta'' Lioy, 1864 *''Leptohylemyia'' Schnabl & Dziedzicki, 1911 *''Leucodelia'' Karl, 1943 *''Monodelia'' Karl, 1943 *''Subdelia'' Karl, 1943 *''Tricharia'' Karl, 1928<ref name="Karl1928"/> *''Trichohylemyia'' Karl, 1943 *''Trigonostoma'' Lioy, 1864 | synonyms_ref =  <ref>{{Cite book|editor=A. Soos & L. Papp |year=1986|title=Catalogue of Palaearctic Diptera. Vol. 13, Anthomyiidae - Tachinidae |publisher=Hungarian Natural History Museum |isbn=978-963-7093-21-0|page=624 pp}}</ref> }}

'''''Delia''''' flies are members of the Anthomyiidae family within the superfamily Muscoidea.<ref name=":0">{{Cite journal|last=Finch|first=S|date=January 1989|title=Ecological Considerations in the Management of Delia Pest Species in Vegetable Crops|journal=Annual Review of Entomology|volume=34|issue=1|pages=117–137|doi=10.1146/annurev.en.34.010189.001001|issn=0066-4170}}</ref> The identification of different species of ''Delia'' can be very difficult for non-specialists as the diagnostic characteristics used for immature and/or female specimens may be inconsistent between species.<ref name=":1">{{Cite journal|last1=Savage|first1=J|last2=Fortiere|first2=A|last3=Fournier|first3=F|last4=Bellavance|first4=V|title=Identification of Delia pest species (Diptera: Anthomyiidae) in cultivated crucifers and other vegetable crops in Canada|journal=Canadian Journal of Arthropod Identification|year=2016|volume=29|pages=1–40|doi=10.3752/cjai.2016.29}}</ref> Past taxonomic keys were not as comprehensive in their identification of ''Delia'' specimens; they were either too reliant on genetic characteristics, focused solely on a specific life stage, or were focused only on certain species.<ref name=":1" /> However current taxonomic keys aim to be more thorough by not only including morphological diagnostics for males, females, and immature specimens of various species, but also their genetic make-up or molecular barcode.<ref name=":1" />

Certain ''Delia'' species are of great economic importance as they are agricultural pests. The larvae of these flies, which tunnel into roots and stems of host plants, can cause considerable yield losses. Although most members of this genus have larvae that feed on stems, flowers, roots, and fruits of plants, a few others have larvae that are leaf miners. As herbivores, ''Delia'' flies can be categorized as a generalist or a specialist depending on their diet.<ref name=":2">{{Cite web|title=Generalist versus Specialist|url=https://www.webpages.uidaho.edu/range556/appl_behave/projects/different_strokes.html|access-date=2020-08-10|website=www.webpages.uidaho.edu}}</ref> Those that can eat and safely digest a wide variety of plants are known as generalists, whereas those that feed on one sole plant type are known as specialists.<ref name=":2" /> Specialists typically have the ability to tolerate and/or enzymatically detoxify the harmful allelochemicals produced by the plants they feed on.<ref>{{Cite journal|last=Johnson|first=K. S.|date=1999|title=Comparative detoxification of plant (Magnolia virginiana) allelochemicals by generalists and specialist saturniid silkmoths.|journal=Journal of Chemical Ecology|volume=25|issue=2|pages=253–269|doi=10.1023/a:1020890628279|bibcode=1999JCEco..25..253J |s2cid=24568858|issn=0098-0331}}</ref> Common specialist species that are detrimental to crops include ''D. radicum'' (cabbage fly) and ''D. floralis'' (turnip root fly), which feed on the roots and/or leaves of Brassica crops, ''D. antiqua'' (onion fly), ''D. platura'' (seed-corn fly), ''D. florilega'' (bean-seed fly), which feed on allium roots and leaves, and ''D. coarctata'' (wheat-bulb flies) which feed on cereals.<ref name=":0" /><ref>{{Cite journal|last1=Soroka|first1=J. J.|last2=Dosdall|first2=L. M.|last3=Olfert|first3=O. O.|last4=Seidle|first4=E.|date=2004-10-01|title=Root maggots (''Delia'' spp., Diptera: Anthomyiidae) in prairie canola (''Brassica napus'' L. and ''B. rapa'' L.): Spatial and temporal surveys of root damage and prediction of damage levels|journal=Canadian Journal of Plant Science|volume=84|issue=4|pages=1171–1182|doi=10.4141/p02-174|issn=0008-4220}}</ref>

== Geographical distribution == The genus ''Delia'' contains approximately 300–340 species worldwide (excluding Neotropical species). At present about 170 species are recorded from the Palaearctic region, and 162 species from the Nearctic region, 44 of which are Holarctic. Afrotropical fauna includes 20 ''Delia'' species.<ref name="Ackland" /> Griffiths <ref name="Griffiths1991a">{{cite journal|last1=Griffiths|first1=G.C.D.|editor1-last=Griffiths|editor1-first=G.C.D.|title=Anthomyiidae|journal=Flies of the Nearctic Region|date=1991|volume=8|issue=part 2. 7|pages=953–1048}}</ref><ref name="Griffiths1991b">{{cite journal|last1=Griffiths|first1=G.C.D.|editor1-last=Griffiths|editor1-first=G.C.D.|title=Anthomyiidae|journal=Flies of the Nearctic Region|date=1991|volume=8|issue=part 2. 8|pages=1049–1240}}</ref><ref name="Griffiths1992">{{cite journal|last1=Griffiths|first1=G.C.D.|editor1-last=Griffiths|editor1-first=G.C.D.|title=Anthomyiidae|journal=Flies of the Nearctic Region|date=1991|volume=8|issue=part 2. 9|pages=1241–1416}}</ref><ref name="Griffiths1993">{{cite journal|last1=Griffiths|first1=G.C.D.|editor1-last=Griffiths|editor1-first=G.C.D.|title=Anthomyiidae|journal=Flies of the Nearctic Region|date=1991|volume=8|issue=part 2. 10|pages=1417–1632}}</ref> described 49 new species in his recent revision of the Nearctic species, nearly a third of the present Nearctic total, and similar intensive revisions in other parts of the world are expected to produce many more, especially in the Middle East, mountainous regions of Central Asia, Nepal, and Mongolia.

==Biology== Morphologically speaking, adult ''Delia'' flies resemble the common housefly and species possess subtle differences in size, colouring, and location and length of bristles throughout the body.<ref name=":1" /> Furthermore, male and female flies experience minor sexual dimorphism.<ref name=":1" />

The larvae of ''Delia'' have three larval instar stages, and the morphology of the larval tubercles and spiracles are used to differentiate between species.<ref name=":1" /> As the larvae of ''Delia'' flies attach and feed on various plant parts, each of their three larval instars have a specialized respiratory system to facilitate survival within the aqueous and acidic environment of the putrefying host plant.<ref>{{Cite journal|last1=Biron|first1=D.G.|last2=Coderre|first2=D.|last3=Fournet|first3=S.|last4=Nénon|first4=J.P.|last5=Le Lannic|first5=J.|last6=Boivin|first6=G.|date=April 2005|title=Larval respiratory systems of two anthomyiid flies, ''Delia radicum'' and ''Delia antiqua'' (Diptera: Anthomyiidae)|journal=The Canadian Entomologist|volume=137|issue=2|pages=163–168|doi=10.4039/n04-071|s2cid=85388683|issn=0008-347X}}</ref> The third larval instar is commonly used for identification purposes of species that are of economic importance.<ref name=":1" />

The eggs of ''Delia'' specimens are generally white in colour and elongated ovular in shape with distinctive hatching pleats on the surface of the egg, which are unique to each species.<ref name=":1" />

== Agricultural pest == Six species of ''Delia'' (''D. antiqua'', ''D. floralis'', ''D. florilega'', ''D. planipalpis'', ''D. platura'', ''D. radicum'') are common agricultural pests during their larval stage, causing severe economic loss throughout North America and Europe.<ref name=":1" /> The most notable species are ''D. radicum'' and ''D. antiqua''.

''Delia radicum'' larvae, commonly known as cabbage maggot, has caused significant damage by feeding and burrowing within the roots of members of the Brassica family including cabbage (''Brassica oleracea''), canola (''Brassica napus''), rutabaga (''Brassica napobrassica''), broccoli (''Brassica oleracea'' var. italica), cauliflower (''Brassica oleracea'' var. botrytis'')'', turnip (''Brassica rapa'' subsp. ''rapa''), and radish (''Raphanus sativus'').<ref name=":0" />

''Delia antiqua'' larvae'','' commonly known as the onion maggot, is a prominent agricultural pest on members of the ''Allium'' genus including onions (''Allium cepa)'', garlics (''Allium sativum''), chives (''Allium schoenoprasum''), shallots (''Allium cepa'' var. ''aggregatum''), and leeks (''Allium porrum'').<ref>{{Cite book|last=Rabinowitch|first=H.D.|editor2-first=James L|editor2-last=Brewster|editor1-first=Haim D|editor1-last=Rabinowitch|date=2018-05-04|title=Onions and Allied Crops|doi=10.1201/9781351075152|isbn=9781351075152}}</ref>

Gravid females will oviposit in the soil near the crops or on the host plant itself, and when the eggs hatch the larvae cause extensive damage to the plants when they feed. For example, ''D. radicum'' maggots feeding on the roots of canola crops cause damage to the plants’ phloem, periderm, and xylem parenchyma.<ref name=":3">{{Cite journal|last1=McDonald|first1=R. S.|last2=Sears|first2=M. K.|date=1992-06-01|title=Assessment of larval feeding damage of the cabbage maggot (Diptera: Anthomyiidae) in relation to oviposition preference on canola |journal=Journal of Economic Entomology|volume=85|issue=3|pages=957–962|doi=10.1093/jee/85.3.957 }}</ref> Damage to the phloem and xylem tissue can disrupt the transportation of photosynthetic products and water, respectively.<ref name=":3" /> Additionally, this damage can also lead to vulnerabilities against pathogenic microorganisms.<ref name=":4">{{Cite journal|last=Griffiths|first=G|date=1986|title=Relative abundance of the root maggots ''Delia radicum'' (L.) and ''D. floralis'' (Fallen) (Diptera: Anthomyiidae) as pests of canola in Alberta|journal=Quaestiones Entomologicae |volume=22|pages=253–260 |url=https://www.biodiversitylibrary.org/item/208880#page/403/mode/1up }}</ref> If the root damage is severe enough it can lead to a variety of issues including stunted growth, lodging, decreased flowering, decreased size and yield of seeds, or plant death.<ref name=":3" />

There are many factors that will affect the susceptibility of a plant to ''Delia'' oviposition, and subsequent larval infestation. These factors include the species or variety of plant, the morphology of certain plant parts (root shape and size, wax levels on leaves, colour of foliage), and the physiology (age, chemical composition of certain secondary plant substances).<ref>{{Cite journal|last1=Hardman |first1=J. A.|last2=Ellis |first2=P. R.|title=Host plant factors influencing the susceptibility of cruciferous crops to cabbage root fly attack|date=November 1978|journal=Entomologia Experimentalis et Applicata|volume=24|issue=3|pages=393–397|doi=10.1111/j.1570-7458.1978.tb02799.x|bibcode=1978EEApp..24..393H |s2cid=85077151 |doi-access=free}}</ref> For example, as a specialist of cruciferous crops, ''D. radicum,'' is attracted to the organic compound isothiocyanates found in these variety of plants in order to identify it as a suitable host.<ref name=":5">{{Cite journal|last1=Tuttle|first1=A. F.|last2=Ferro|first2=D. N.|last3=Idoine|first3=K.|date=April 1988|title=Role of visual and olfactory stimuli in host finding of adult cabbage root flies, ''Delia radicum'' |journal=Entomologia Experimentalis et Applicata|volume=47|issue=1|pages=37–44|doi=10.1111/j.1570-7458.1988.tb02279.x|bibcode=1988EEApp..47...37T |s2cid=85857646 }}</ref> In addition to being attracted to the olfactory cues of this type of plant, visual cues such as colour, position, and visual prominence of the flowers influence which plant they will infest.<ref name=":5" /> In addition to the plant itself, studies with ''D. radicum'' and ''D. floralis'' have shown that other environmental factors such as soil moisture,<ref name=":4" /> average daily air temperature, and total precipitation<ref>{{Cite journal|last1=Turnock|first1=W.J.|last2=Timlick|first2=B.|last3=Galka|first3=B.E.|last4=Palaniswamy|first4=P.|title=Root maggot damage to canola and the distribution of ''Delia'' spp. (Diptera: Anthomyiidae) in Manitoba|date=February 1992|journal=The Canadian Entomologist|volume=124|issue=1|pages=49–58|doi=10.4039/ent12449-1 |s2cid=87413674 }}</ref> can all have a positive correlation with the crop’s susceptibility to infestation.

== Current pest control management ==

=== Cultural controls ===

==== Crop hygiene ==== Good crop hygiene is one cultural control used to minimize ''Delia'' infestations, particularly ''D. antiqua'' and ''D. radicum''.<ref name=":6">{{Cite journal|last1=Finch|first1=S.|last2=Eckenrode|first2=C. J.|date=1985-06-01|title=Influence of Unharvested, Cull-pile, and Volunteer Onions on Populations of Onion Maggot (Diptera: Anthomyiidae)|journal=Journal of Economic Entomology|volume=78|issue=3|pages=542–546|doi=10.1093/jee/78.3.542|issn=1938-291X}}</ref> Studies have shown that damaged or crushed onion bulbs left behind after harvest were major sources of ''D. antiqua'' food and an overwintering site.<ref name=":6" /> Damaged plants release volatile chemicals that attract gravid females while the wounds on the plants provide easy access to newly emerged larvae.<ref name=":6" /> As such, removing waste crop material from harvested fields is recommended to decrease overwintering populations.<ref name=":6" /> Cull piles of harvested onions and volunteer plants from onion fields were originally believed to also be a major source of infestation and thus must be protected against the flies. However, recent studies have observed that neither of these sites are important infestation sources as conditions within deep cull piles are unfavourable to larval survival and larvae are unable to establish on undamaged volunteer plants in the spring.<ref name=":6" />

==== Crop rotation ==== Crop rotations are often used to avoid the depletion of soil nutrients and the buildup of soil pathogens.<ref name=":0" /> However, crop rotation can serve to geographically distance a crop from known locations of ''Delia'' populations by planting a crop from a different plant family following the harvest of the host crop favoured by the pest.<ref name=":7">{{Cite web|title=Cultural methods of pest, primarily unsect, control|url=https://eap.mcgill.ca/publications/eap58.htm|access-date=2020-08-10|website=eap.mcgill.ca}}</ref> While crop rotation may be effective on certain soil- inhabiting pests that have low mobility and low dispersal capabilities, this practice is not commonly seen as a control for specialist ''Delia'' species such as ''D. radicum'' and ''D. antiqua'' since they can disperse 2000–3000 meters from the site of infestation and can have a wide host range.<ref>{{Cite journal|last1=FINCH|first1=S.|last2=SKINNER|first2=G.|date=September 1975|title=Dispersal of the cabbage root fly|journal=Annals of Applied Biology|volume=81|issue=1|pages=1–19|doi=10.1111/j.1744-7348.1975.tb00490.x|issn=0003-4746}}</ref><ref name=":8">{{Cite book|last=Loosjes, M.|title=Ecology and genetic control of the onion fly, Delia antiqua (Meigen)|date=1976|publisher=Centre for Agricult. Publishing and Documentation|oclc=252516603}}</ref>

==== Crop and soil covers ==== Covering seed beds with a physical material, such as cheesecloth, or covering the soil of crops with tarred felt discs can prevent gravid ''Delia'' flies from laying their eggs on the crop.<ref name=":0" /> Covering crops as a cultural control may also complement and improve the use of biological controls such as entomopathogenic fungi and nematodes as it produces a high-humidity climate that is favourable to these pathogens.<ref name=":0" /> However, completely covering crops is not a common practice as the crop covers were found to damage crop growth, can be expensive, and are time consuming to install and remove.<ref name=":0" />

==== Sowing, planting, and harvesting times ==== Establishing appropriate times to sow or plant crops has multiple benefits as a cultural control. Primarily, the goal is to avoid invasion by the pest, reduce crop vulnerability to oviposition, and decrease infection from insect vectors.<ref name=":0" /><ref name=":7" /> By sowing or planting at specific times during the growing season, plants are mature enough to tolerate low levels of attack from pests, and farmers have enough time to compensate for crops that have been damaged or destroyed.<ref name=":0" /><ref name=":7" /><ref>{{Cite journal|last1=Silver|first1=Natalie|last2=Hillier|first2=Kirk|last3=Blatt|first3=Suzanne|date=2018-08-22|title=Management of Delia (Diptera: Anthomyiidae) through selectively timed planting of Phaseolus vulgaris (Fabaceae) in Atlantic Canada|journal=The Canadian Entomologist|volume=150|issue=5|pages=663–674|doi=10.4039/tce.2018.36|s2cid=92847584|issn=0008-347X}}</ref> Additionally, choosing a planting time when weather conditions are unfavourable to pests or synchronized with the emergence of natural enemies of the pests can also mitigate pest populations.<ref name=":7" />

=== Chemical controls ===

==== Insecticides ==== In the past, chemical insecticides were used extensively to prevent ''Delia'' infestations. These insecticides were primarily organochlorines,<ref name=":0" /> organophosphates, and chlorinated hydrocarbons.<ref name=":9">{{Cite journal|last1=Shuhang|first1=Wang|last2=Voorrips|first2=Roeland E.|last3=Steenhuis-Broers|first3=Greet|last4=Vosman|first4=Ben|last5=van Loon|first5=Joop J. A.|date=2016-06-01|title=Antibiosis resistance against larval cabbage root fly, Delia radicum, in wild Brassica-species|journal=Euphytica|volume=211|issue=2|pages=139–155|doi=10.1007/s10681-016-1724-0|bibcode=2016Euphy.211..139S |issn=0014-2336|doi-access=free}}</ref> However, the chemicals used were generally hazardous to the environment and thus are banned or under review and could be banned.<ref name=":9" /> Furthermore, in some cases, such as ''D. antiqua'' flies in the Netherlands, the pests developed a resistance to the insecticides and crops continued to be destroyed.<ref name=":8" /> This rise in resistance and the hazard to the environment has prompted the search for a biological control instead.

=== Genetic controls ===

==== Sterile insect technique ==== The sterilization of insects in order to minimize population numbers can be accomplished either by using chemosterilants on laboratory reared males and then releasing them into the fields ({{abbrlink|SIT|Sterile insect technique}}) or using chemosterilants on existing populations in the field.<ref>{{Cite journal|last=Borkovec|first=A. B.|date=April 1976|title=Control and management of insect populations by chemosterilants |journal=Environmental Health Perspectives|volume=14|pages=103–107|doi=10.1289/ehp.7614103|pmid=789057|pmc=1475093 |bibcode=1976EnvHP..14..103B |doi-access=free}}</ref> Chemosterilants used in some studies include tepa [tris-(l -aziridinyl) phosphine oxide] which is very effective at sterilizing adult flies but less so on eggs.<ref name=":10">{{Cite journal|last1=Finch|first1=S.|last2=Skinner |first2=G.|date=April 1973|title=Chemosterilization of the cabbage root fly under field conditions |journal=Annals of Applied Biology|volume=73|issue=3|pages=243–258|doi=10.1111/j.1744-7348.1973.tb00931.x|pmid=4701060 }}</ref>

The effectiveness of sterilization to as a genetic control against ''Delia spp.'' populations has had mixed results. One study revealed that when chemosterilants were used on exiting populations of ''D. radicum'', multiple factors, such as the tendency for females to disperse, reduction in the competitiveness of sterile males, and the failure of males to re-disperse once sterilized, all limited the population of sterility in field insects therefore not decreasing oviposition rates.<ref name=":10" /> Furthermore, other studies that performed SIT using chemosterilants on laboratory reared ''D. radicum'' males instead of existing populations found that they were no more effective despite releasing significantly more sterile males.<ref>{{Cite journal|last=Hertveldt|first=L|date=1980|title=Development of the sterile insect release method against the cabbage root fly, ''Delia brassicae'' (B.), in north Belgium |journal=IOBC-WPRS Bulletin|volume=3|pages=63–87}}</ref>

Contrastingly, other studies in the Netherlands have recorded more success in sterilizing ''D. antiqua'' without lowering their competitiveness and thus were able to outcompete the wild population.<ref name=":11">{{Cite book|last=Ticheler|first=J.|date=1980|chapter=Sterile-male technique for control of the onion maggot, ''Delia antiqua'' |title=Integrated Control of Insect Pests in the Netherlands |editor=A.K. Minks |editor2=P. Gruys |publisher=Centre for Agricultural Publishing and Documentation |location=Wageningen |url=https://edepot.wur.nl/411242}}</ref> However, this method requires that the sterile flies are released for at least five years before they start having a significant effect on population numbers<ref name=":11" />''.'' Additionally, SIT projects on ''D. antiqua'' in Quebec have also shown a reduction in fertile adult populations, and the continuation of this technique is expected to result in a decrease in both the release rates of sterile insects and the overall cost of the program.<ref>{{Cite web|last=Cranmer|first=Travis|date=2019-03-01|title=Can Onion Maggot be managed without insecticides?|url=https://onvegetables.com/2019/03/01/can-onion-maggot-be-managed-without-insecticides/|access-date=2020-08-10|website=ONvegetables|language=en-US}}</ref>

=== Biological controls ===

==== Parasitoids ==== Studies have shown that there are three abundant and widely distributed parasitoids of ''Delia'' species - ''Trybliographa rapae, Aleochara bilineata,'' and ''Aleochara bipustulata.''

''Trybliographa rapae'' is a parasitic wasp from the Figitidae family. The larvae of these wasps are a koinobiont endoparasite to several species of ''Delia'' including ''D. radicum, D. floralis,'' and ''D. platura''.<ref name=":12">{{Cite journal|last1=Wishart|first1=Geo.|last2=Monteith|first2=Elizabeth|date=April 1954|title=Trybliographa rapae (Westw.) (Hymenoptera: Cynipidae), A Parasite of Hylemya spp. (Diptera: Anthomyiidae)|journal=The Canadian Entomologist|volume=86|issue=4|pages=145–154|doi=10.4039/ent86145-4|s2cid=86350534 |issn=0008-347X}}</ref> As Delia larvae feed on the roots of cruciferous plants and other crops, they damage the tissue which then induces the plant to emit volatile compounds.<ref name=":13">{{Cite journal|last1=Neveu|first1=N.|last2=Grandgirard|first2=J.|last3=Nenon|first3=J. P.|last4=Cortesero|first4=A. M.|date=2002|title=Systemic release of herbivore-induced plant volatiles by turnips infested by concealed root-feeding larvae Delia radicum L|journal=Journal of Chemical Ecology|volume=28|issue=9|pages=1717–1732|doi=10.1023/a:1020500915728|pmid=12449501|bibcode=2002JCEco..28.1717N |s2cid=16413139|issn=0098-0331}}</ref> These volatiles act as chemical cues to attract predators and parasitoids of the herbivore feeding on the plant as a defensive measure.<ref name=":13" /> Female ''T. rapae'' are attracted to these signals and use them to identify the location of ''Delia'' larvae.<ref name=":13" /> Once attracted to the infested crops, ''T. rapae'' females may use antennal searching, ovipositor probing, or vibrotaxis to locate the ''Delia'' larvae buried within the plant and lay their eggs within them. ''Trybliographa rapae'' may parasitize any of the three larval instars of ''Delia''.<ref name=":13" /><ref>{{Cite journal|last1=Hemachandra|first1=K.S.|last2=Holliday|first2=N.J.|last3=Mason|first3=P.G.|last4=Soroka|first4=J.J.|last5=Kuhlmann|first5=U.|date=October 2007|title=Comparative assessment of the parasitoid community of Delia radicum in the Canadian prairies and Europe: A search for classical biological control agents|journal=Biological Control|volume=43|issue=1|pages=85–94|doi=10.1016/j.biocontrol.2007.07.005|bibcode=2007BiolC..43...85H |issn=1049-9644}}</ref>

''Aleochara bilineata'' is a rove beetle within the Staphylinidae family. The adult specimens are a dominant predator of the eggs and larvae of ''D. radicum, D. platura, D. floralis,'' and ''D. planipalis''.<ref name=":14">{{Cite journal|last1=Broatch|first1=J. S.|last2=Dosdall|first2=L. M.|last3=Yang|first3=R.-C.|last4=Harker|first4=K. N.|last5=Clayton|first5=G. W.|date=2008-12-01|title=Emergence and Seasonal Activity of the Entomophagous Rove Beetle ''Aleochara bilineata'' (Coleoptera: Staphylinidae) in Canola in Western Canada|journal=Environmental Entomology|volume=37|issue=6|pages=1451–1460|doi=10.1603/0046-225x-37.6.1451|pmid=19161688|s2cid=12838808|issn=0046-225X}}</ref> Additionally, the first instar larvae of ''A. bilineata'' are ectoparasites of the ''Delia'' pupae.<ref name=":14" /> Female ''A''. ''bilineata'' will oviposit near the roots of the cruciferous crops, where ''Delia'' larvae are most likely to be found, and once the eggs hatch, the parasitic instars will chew an entrance hole on the vulnerable puparial wall wherein it will feed on the pupae within and undergoes two more instar stages before pupating.<ref>{{Cite journal|last1=Royer|first1=Lucie|last2=Lannic|first2=Joseph|last3=Nenon|first3=Jean-Pierre|last4=Boivin|first4=Guy|date=May 1998|title=Response of first-instar Aleochara bilineata larvae to the puparium morphology of its dipteran host|journal=Entomologia Experimentalis et Applicata|volume=87|issue=2|pages=217–220|doi=10.1046/j.1570-7458.1998.00323.x|bibcode=1998EEApp..87..217R |s2cid=86216427|issn=0013-8703|doi-access=free}}</ref> The emergence of ''A. bilineata'' is synchronized with the egg laying of ''Delia'' species since the first instars of ''A. bilineata'' may overwinter within the host pupae in order to emerge as adult in the warmer weather of spring.<ref name=":14" /> Competition occurs between ''A. bilineata'' and ''T. rapae'', which has been shown to be harmful to both specimens, but particularly ''T. rapae''.<ref name=":12" />

''Aleochara bipustulata'' is another species of rove beetle that is a predator to ''Delia'' spp. however much smaller than that of ''A. bilineata''.<ref name=":15">{{Cite journal|last=Wishart|first=George|date=October 1957|title=Surveys of Parasites of Hylemya spp. (Diptera: Anthomyiidae) That Attack Cruciferous Crops in Canada|journal=The Canadian Entomologist|volume=89|issue=10|pages=450–454|doi=10.4039/ent89450-10|s2cid=86037509 |issn=0008-347X}}</ref> Its life cycle is very similar to that of ''A. bilineata,'' but overall it is significantly less abundant and is currently not found in North America.<ref name=":16">{{Cite journal|last1=Wilkes|first1=A.|last2=Wishart|first2=G.|date=September 1953|title=Studies on parasites of root maggots (Hylemya spp.; Diptera: Anthomyiidae) in the Netherlands in relation to their control in Canada|journal=Tijdschrift over Plantenziekten|volume=59|issue=5|pages=185–188|doi=10.1007/bf01988192|bibcode=1953EJPP...59..185W |s2cid=37965812|issn=0028-2944}}</ref> As opposed to other predators, ''A. bipustulata'' favours ''D. platura'' instead of ''D. radicum'' as the puparial wall is much thinner.<ref name=":15" /> However, some specimens were found in smaller pupae of ''D.'' ''radicum'' and rarely found in ''D. floralis'', as these larvae are significantly larger than other ''Delia'' species.<ref name=":15" />

Two other parasitic wasps of ''Delia'' species were found in North America, ''Phygadeuon sp.'' and ''Aphaereta'' ''sp.,'' however, their presence were so scarce that it is suggested that they may have a more favoured host other than the root maggots.<ref name=":16" />

==== Entomopathogenic fungi ==== Application of entomopathogenic fungus as a biological control may involve spraying conidia on crops at the onset of egg hatching so that the fungus is present in the soil to reduce larval populations, ideally before they penetrate the plants.<ref>{{Cite journal|last1=Bruck|first1=Denny J.|last2=Snelling|first2=Jane E.|last3=Dreves|first3=Amy J.|last4=Jaronski|first4=Stefan T.|date=June 2005|title=Laboratory bioassays of entomopathogenic fungi for control of Delia radicum (L.) larvae|journal=Journal of Invertebrate Pathology|volume=89|issue=2|pages=179–183|doi=10.1016/j.jip.2005.02.007|pmid=16087004|bibcode=2005JInvP..89..179B |issn=0022-2011|url=https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1327&context=usdaarsfacpub|url-access=subscription}}</ref>

While multiple species of fungi have been identified to kill ''Delia'' species, and therefore may possibly act as a biological control, there are several problems associated with using entomopathogenic fungi effectively. First, while fungal pathogens may thrive in controlled laboratory settings and are successful in killing larvae and/or adults, they may be incredibly susceptible to fluctuating environmental factors, such as temperature and moisture, which can alter their efficacy as a biological control.<ref name=":0" />

Second, the glucosinolates produced by brassicaceous plants when they are physically damaged, infected or fed on by pests will be converted into isothiocyanates.<ref name=":17">{{Cite journal|last1=Vanninen|first1=I.|last2=Hokkanen|first2=H.|last3=Tyni-Juslin|first3=J.|date=March 1999|title=Attempts to control cabbage root flies Delia radicum L. and Delia floralis (Fall.) (Dipt., Anthomyiidae) with entomopathogenic fungi: laboratory and greenhouse tests|journal=Journal of Applied Entomology|volume=123|issue=2|pages=107–113|doi=10.1046/j.1439-0418.1999.00315.x|s2cid=84361973|issn=0931-2048}}</ref> Isothiocyanates are chemical compounds that can be toxic to pathogenic fungi which can result in inhibition of germination and growth.<ref name=":17" /><ref>{{Cite journal|last1=Klingen|first1=I.|last2=Hajek|first2=A.|last3=Meadow|first3=R.|last4=Renwick|first4=J.A.A.|date=2002|title=Effect of brassicaceous plants on the survival and infectivity of insect pathogenic fungi|journal=BioControl|volume=47|issue=4|pages=411–425|doi=10.1023/a:1015653910648|bibcode=2002BioCo..47..411K |s2cid=35651452|issn=1386-6141}}</ref> Studies have suggested that isothiocyanates can cause fungicidal activity by directly interacting with the fungal spores or indirectly through a three-trophic-level interaction mediated by the host insect.<ref name=":17" />

Studies of laboratory experiments have observed that ''Metarhizium anisopliae, Beauveria bassiana,'' and ''Paecilomyces fumosoroseus'' are all pathogenic to the second and third larval instars of ''D. radicum'' and ''D. floralis''.<ref name=":17" /> ''Metarhizium anisopliae'' affects larvae directly exposed during application and larvae that came into contact with the fungus in the soil post-application.<ref name=":17" /> ''Entomophthora muscae'' is another entomopathogenic fungi that thrives in warm, moist environments, and can infect and kill adult ''Delia'' flies, primarily ''D. antiqua''.<ref>{{Cite journal|last1=Carruthers|first1=R. I.|last2=Haynes|first2=D. L.|date=1986-12-01|title=Temperature, Moisture, and Habitat Effects on Entomophthora muscae (Entomophthorales: Entomophthoraceae) Conidial Germination and Survival in the Onion Agroecosystem|journal=Environmental Entomology|volume=15|issue=6|pages=1154–1160|doi=10.1093/ee/15.6.1154|issn=1938-2936}}</ref> ''Strongwell-sea castrans'', a fungus commonly found in Europe as opposed to North America, is known to sterilize the adult flies of ''D. radicum''.<ref>{{Cite journal|last1=Nair|first1=K.S.S.|last2=McEwen|first2=F.L.|date=November 1973|title=Strongwellsea castrans (Phycomycetes: Entomophthoraceae), a fungal parasite of the adult cabbage maggot, Hylemya brassicae (Diptera: Anthomyiidae)|journal=Journal of Invertebrate Pathology|volume=22|issue=3|pages=442–449|doi=10.1016/0022-2011(73)90175-4|bibcode=1973JInvP..22..442N |issn=0022-2011}}</ref>

==== Entomopathogenic nematodes ==== Entomopathogenic nematodes are parasitic worms that have potential as a biological control agent as they have gram-negative, asporous, entomopathogenic bacteria which can infect and subsequently kill a wide variety of insect hosts, including ''Delia'' spp.<ref name=":18">{{Cite journal|last=Morris|first=O. N.|title=Susceptibility of 31 Species of Agricultural Insect Pests to the Entomogenous Nematodes Steinernema Feltiae and Heterorhabditis Bacteriophora|date=April 1985|journal=The Canadian Entomologist|volume=117|issue=4|pages=401–407|doi=10.4039/ent117401-4|s2cid=85334834 |issn=0008-347X}}</ref> The nematodes enter the insect host through openings such as the mouth, anus, and spiracles, and once inside the body cavity will release bacteria, e.g. ''Xenorhabdus nematophilus'' and ''Xenorhabdus luminescens,'' which will proliferate within the insect’s hemocoel causing death.<ref name=":18" /> If nematodes are applied to the soil where the ''Delia'' eggs are laid, the larvae that hatch will be directly exposed to the nematodes.<ref name=":18" />

Studies have shown that both pupae and adults of ''D. radicum'' and ''D. antiqua'' were susceptible to nematodes ''Steinernema feltiae'' and ''Heterorhabditis bacteriophora'', with ''D. antiqua'' showing greater mortality than D. radicum.<ref name=":18" /> However, since these studies were performed under laboratory conditions that favoured the nematode and were suboptimal to the insect host, the effectiveness of nematodes as a biological control may not be fully replicated in the field.<ref name=":0" />

== Common species == {| class="wikitable" |+Table 1: Nomenclature of the most significant agricultural pests of ''Delia'' flies !Scientific Nomenclature !Common name !Other Nomenclature |- |''Delia antiqua'' (Meigen, 1826) |Onion maggot/fly |''Hylemyia antiqua'' ''Hylemya antiqua'' |- |''Delia coarctata'' (Fallén, 1925) |Wheat Bulb maggot/fly |''Hylemia garbiglietti'' (Rondani) ''Hylemya coarctata'' (Fallén) |- |''Delia floralis'' (Fallén, 1924) |Turnip maggot/fly |''Hylemyia crucifera'' (Huckett)

''Hylemya crucifera''

''Hylemya floralis'' |- |''Delia florilega'' (Zetterstedt, 1845) |Bean Seed maggot/fly |''Hylemya trichodactyla'' (Rondani)

''Hylemyia trichodactyla''

''Chortophila cilicrura'' (Rondani)

''Hylemya cilicrura'' ''Hylemyia cilicrura'' |- |''Delia radicum'' (Linnaeus, 1758) |Cabbage maggot/fly |''Hylemya brassicae'' (Bouché)

''Hylemyia brassicae'' ''Erioischa brassicae.'' |}

==Species list== These species belong to the genus ''Delia''<ref name=catlife/> {{col div|colwidth=22em}} * ''Delia abruptiseta'' (Ringdahl, 1935) * ''Delia absidata'' Xue & Du, 2008<ref name="XueDu2008"/> * ''Delia abstracta'' (Huckett, 1965) * ''Delia abundepilosa'' Hennig, 1974 * ''Delia acadiana'' Griffiths, 1991 * ''Delia aconiti'' (Ringdahl, 1948) * ''Delia aemene'' (Walker, 1849) * ''Delia alaba'' (Walker, 1849) * ''Delia alaskana'' (Huckett, 1966) * ''Delia alatavensis'' Hennig, 1974 * ''Delia albula'' (Fallén, 1825) * ''Delia alternata'' (Huckett, 1951) * ''Delia ancylosurstyla'' Xue, 2002 * ''Delia andersoni'' (Malloch, 1924) * ''Delia angusta'' (Stein, 1898) * ''Delia angustaeformis'' (Ringdahl, 1933) * ''Delia angustifrons'' (Meigen, 1826) * ''Delia angustissima'' (Stein, 1907) * ''Delia angustiventralis'' (Huckett, 1965) * ''Delia angustiventris'' (Zetterstedt, 1845) * ''Delia aniseta'' (Stein, 1920) * ''Delia annularis'' Tiensuu, 1946 * ''Delia antiqua'' (Meigen, 1826) * ''Delia apicifloralis'' Xue, 2002 * ''Delia aquitima'' (Huckett, 1929) * ''Delia arambourgi'' (Séguy, 1938) * ''Delia arenicola'' Griffiths, 1991 * ''Delia armata'' (Stein, 1920) * ''Delia atrifrons'' Fan, 1982 * ''Delia attenuata'' (Malloch, 1920) * ''Delia augusta'' (Huckett, 1965) * ''Delia auricolor'' Suwa, 1974 * ''Delia aurosialata'' Fan, 1993 * ''Delia bacilligera'' Hennig, 1974 * ''Delia banksiana'' Griffiths, 1991 * ''Delia beringiana'' Griffiths, 1993 * ''Delia bernardinensis'' Griffiths, 1991 * ''Delia bifascinata'' Griffiths, 1992 * ''Delia bipartita'' Suwa, 1977 * ''Delia bipartitoides'' Michelsen, 2007<ref name="Michelsen2007"/> * ''Delia bisciliata'' (Emden, 1941) * ''Delia bisetosa'' (Stein, 1907) * ''Delia bracata'' (Rondani, 1866)<ref name="Ackland"/> * ''Delia brassicaeformis'' (Ringdahl, 1926) * ''Delia brevipalpis'' Xue & Zhang, 1996 * ''Delia brunnescens'' (Zetterstedt, 1845) * ''Delia bucculenta'' (Coquillett, 1904) * ''Delia byersi'' Griffiths, 1993 * ''Delia caledonica'' Assis-Fonseca, 1966 * ''Delia calviloba'' Griffiths, 1993 * ''Delia cameroonica'' (Ackland, 2008)<ref name="Ackland"/> * ''Delia canalis'' Fan & Wu, 1984 * ''Delia canariensis'' Hennig, 1974 * ''Delia capdellae'' Michelsen, 2012 * ''Delia capensis'' (Malloch, 1924) * ''Delia capito'' (Coquillett, 1902) * ''Delia cardui'' (Meigen, 1826) * ''Delia carduiformis'' (Schnabl in Schnabl & Dziedzicki, 1911) * ''Delia carri'' Griffiths, 1991 * ''Delia cerealis'' (Gillette, 1904) * ''Delia chillcotti'' Griffiths, 1993 * ''Delia chirisana'' Suh & Kwon, 1986 * ''Delia chortophilina'' (Hennig, 1969) * ''Delia cilifera'' (Malloch, 1918) * ''Delia cilitarsis'' Hennig, 1974 * ''Delia clandestina'' Griffiths, 1991 * ''Delia clavata'' Griffiths, 1993 * ''Delia coarctata'' (Fallén, 1825) * ''Delia coarctoides'' Michelsen, 2007<ref name="Michelsen2007"/> * ''Delia coei'' Ackland, 1967 * ''Delia commixta'' (Séguy, 1925) * ''Delia concorda'' (Huckett, 1966) * ''Delia conjugata'' Deng & Li, 1994 * ''Delia conversatoides'' Xue & Zhang, 1996 * ''Delia coronariae'' (Hendel, 1925) * ''Delia cortesiana'' Griffiths, 1991 * ''Delia cregyoglossa'' (Huckett, 1965) * ''Delia crinita'' Hennig, 1974 * ''Delia criniventris'' (Zetterstedt, 1860) * ''Delia cuneata'' Tiensuu, 1946 * ''Delia cupricrus'' (Walker, 1849) * ''Delia curvipes'' (Malloch, 1918) * ''Delia curvistylata'' Suwa, 2013 * ''Delia cyclocerca'' Hsue, 1981 * ''Delia danae'' Griffiths, 1992 * ''Delia dentiaedeagus'' Xue & Du, 2017 * ''Delia deviata'' (Huckett, 1965) * ''Delia diluta'' (Stein, 1916) * ''Delia discalis'' (Séguy, 1925) * ''Delia dissimilipes'' (Huckett, 1965) * ''Delia diversa'' (Wiedemann, 1830) * ''Delia dolichosternita'' Cao, Liu & Xue, 1985 * ''Delia dovreensis'' Ringdahl, 1954 * ''Delia duplicipectina'' Fan, 1993 * ''Delia echinata'' (Séguy, 1923) * ''Delia echinopyga'' Suwa, 1974 * ''Delia egleformis'' (Huckett, 1929) * ''Delia elongata'' (Pokorny, 1889) * ''Delia endorsina'' Ackland, 2008<ref name="Ackland"/> * ''Delia euremena'' Griffiths, 1991 * ''Delia eurymetopa'' Griffiths, 1993 * ''Delia expansa'' Suh & Kwon, 1985 * ''Delia extensa'' (Huckett, 1951) * ''Delia extenuata'' (Huckett, 1952) * ''Delia fabricii'' (Holmgren, 1872) * ''Delia falciforceps'' Xue & Zhang, 1996 * ''Delia fallax'' (Loew, 1873) * ''Delia fasciventris'' (Ringdahl, 1933) * ''Delia felsicanalis'' Fan & Wu, 1984 * ''Delia fimbrifascia'' Xue & Du, 2009 * ''Delia flavibasis'' (Stein, 1903) * ''Delia flavicommixta'' Xue & Zhang, 1996 * ''Delia flavipes'' Tian & Ma, 1999 * ''Delia flavitibiella'' Hennig, 1974 * ''Delia flavogrisea'' (Ringdahl, 1926) * ''Delia floraliformis'' Hennig, 1974 * ''Delia floralis'' (Fallén, 1824) * ''Delia floricola'' Robineau-Desvoidy, 1830 * ''Delia florilega'' (Zetterstedt, 1845) * ''Delia formosana'' Suwa, 1994 * ''Delia fracta'' (Malloch, 1918) * ''Delia frontella'' (Zetterstedt, 838]) * ''Delia frontulenta'' (Huckett, 1929) * ''Delia fulvescens'' (Huckett, 1966) * ''Delia fulviposticrus'' Li & Deng, 1981 * ''Delia gallica'' Hennig, 1974 * ''Delia gansuensis'' Fan, 1988 * ''Delia garretti'' (Huckett, 1929) * ''Delia giresunensis'' Hennig, 1974 * ''Delia glabritheca'' (Huckett, 1966) * ''Delia gracilibacilla'' Chen, 1982 * ''Delia gracilipes'' (Malloch, 1920) * ''Delia gracilis'' (Stein, 1907) * ''Delia groenlandica'' Griffiths, 1993 * ''Delia heraclei'' Griffiths, 1993 * ''Delia hirticrura'' (Rondani, 1871) * ''Delia hirtitibia'' (Stein, 1916) * ''Delia hohxiliensis'' Xue & Zhang, 1996 * ''Delia hudsonica'' Griffiths, 1993 * ''Delia hystricosternita'' Hsue, 1981 * ''Delia impilosa'' Suwa, 1977 * ''Delia inconspicua'' (Huckett, 1924) * ''Delia ineptifrons'' (Huckett, 1951) * ''Delia integralis'' (Huckett, 1965) * ''Delia interflua'' (Pandellé, 1900) * ''Delia intimata'' (Huckett, 1965) * ''Delia ismayi'' (Ackland, 2008)<ref name="Ackland"/> * ''Delia jilinensis'' Chen, 1988 * ''Delia judicariae'' (Pokorny, 1893) * ''Delia kigeziana'' (Emden, 1941) * ''Delia kullensis'' (Ringdahl, 1933) * ''Delia kumatai'' Suwa, 1977 * ''Delia lamellicauda'' (Huckett, 1952) * ''Delia lamelliseta'' (Stein, 1900) * ''Delia lamellisetoides'' Hsue, 1981 * ''Delia lasiosternum'' (Huckett, 1965) * ''Delia latifrons'' (Ackland, 1971) * ''Delia latissima'' (Fan, Ma & Li, 1982) * ''Delia lavata'' (Boheman, 1863) * ''Delia leechi'' Griffiths, 1993 * ''Delia leptinostylos'' (Huckett, 1965) * ''Delia leucophoroides'' Griffiths, 1991 * ''Delia linearis'' (Stein, 1898) * ''Delia lineariventris'' (Zetterstedt, 1845) * ''Delia lobistyla'' Griffiths, 1991 * ''Delia longiabdomina'' Xue & Du, 2017 * ''Delia longiarista'' Xue, 2002 * ''Delia longicauda'' (Strobl, 1898)<ref name="Strobl1893"/> * ''Delia longicercula'' Yudin, 1976 * ''Delia longimastica'' Xue & Zhang, 1996 * ''Delia longisetigera'' Fan, 1984 * ''Delia longitheca'' Suwa, 1974 * ''Delia lophota'' (Pandellé, 1900) * ''Delia lupini'' (Coquillett, 1901) * ''Delia lupinoides'' Griffiths, 1993 * ''Delia mackinleyana'' Griffiths, 1993 * ''Delia madagascariensis'' (Ackland, 2008)<ref name="Ackland"/> * ''Delia madoensis'' Fan, 1988 * ''Delia majuscula'' (Pokorny, 1889) * ''Delia manitobensis'' Griffiths, 1992 * ''Delia martini'' Griffiths, 1993 * ''Delia mastigella'' Xue & Zhang, 1996 * ''Delia mastigophalla'' Xue, Wang & Li, 1993 * ''Delia megacephala'' (Huckett, 1966) * ''Delia megatricha'' (Kertész, 1901) * ''Delia metatarsata'' (Stein, 1914) * ''Delia mexicana'' Griffiths, 1991 * ''Delia micans'' Griffiths, 1991 * ''Delia minutigrisea'' Xue & Zhang, 1996 * ''Delia montana'' (Malloch, 1919) * ''Delia montezumae'' (Griffiths, 1991) * ''Delia monticola'' (Huckett, 1966) * ''Delia montium'' Hennig, 1974 * ''Delia montivagans'' (Huckett, 1952) * ''Delia mutans'' (Huckett, 1929) * ''Delia nemoralis'' (Huckett, 1965) * ''Delia nemostylata'' Deng & Li, 1984 * ''Delia neomexicana'' (Malloch, 1918) * ''Delia nepalensis'' Ackland, 1967 * ''Delia nigeriposticrus'' Xue & Du, 2018 * ''Delia nigrescens'' (Rondani, 1877) * ''Delia nigriabdominis'' Xue, 2001 * ''Delia nigribasis'' (Stein, 1907) * ''Delia nigricaudata'' (Huckett, 1929) * ''Delia nigrihalteres'' Xue & Du, 2017 * ''Delia nigripennis'' Griffiths, 1991 * ''Delia nivalis'' Griffiths, 1991 * ''Delia normalis'' (Malloch, 1919) * ''Delia notobata'' Griffiths, 1991 * ''Delia nubilalis'' (Huckett, 1966) * ''Delia nudicosta'' (Ringdahl, 1949) * ''Delia opacitas'' (Huckett, 1965) * ''Delia oppidans'' (Huckett, 1929) * ''Delia oregonensis'' Griffiths, 1991 * ''Delia orwelliana'' Griffiths, 1993 * ''Delia pacifica'' Griffiths, 1993 * ''Delia pallipennis'' (Zetterstedt, 1838) * ''Delia pamirensis'' Hennig, 1974 * ''Delia pansihirta'' Jin & Fan, 1981 * ''Delia paradisi'' Xue, 2018<ref name="DuXue2018"/> * ''Delia parafrontella'' Hennig, 1974 * ''Delia partivitra'' Fan, 1993 * ''Delia parvicanalis'' Fan, 1984 * ''Delia paupercula'' Griffiths, 1991 * ''Delia pectinator'' Suwa, 1984 * ''Delia pectinitibia'' Jin & Fan, 1981 * ''Delia penicillaris'' (Rondani, 1866) * ''Delia penicillella'' Fan, 1984 * ''Delia penicilliventris'' Ackland, 2010 * ''Delia penicillosa'' Hennig, 1974 * ''Delia persica'' Hennig, 1974 * ''Delia pilicerca'' Suwa, 1974 * ''Delia pilifemur'' (Ringdahl, 1933) * ''Delia pilimana'' (Stein, 1920) * ''Delia piliseritibia'' Fan & Zheng, 1993 * ''Delia pilitarsis'' (Stein, 1920) * ''Delia pilitibia'' (Stein, 1916) * ''Delia piliventris'' (Pokorny, 1889) * ''Delia piniloba'' Hsue, 1981 * ''Delia planipalpis'' (Stein, 1898) * ''Delia platura'' (Meigen, 1826) * ''Delia pluvialis'' (Malloch, 1918) * ''Delia podagricicauda'' Xue, 1997 * ''Delia polaris'' Griffiths, 1991 * ''Delia propinquina'' (Huckett, 1929) * ''Delia prostriata'' (Huckett, 1965) * ''Delia pruinosa'' (Zetterstedt, 1845) * ''Delia pseudechinata'' Griffiths, 1991 * ''Delia pseudextensa'' Griffiths, 1992 * ''Delia pseudofugax'' (Strobl, 1898)<ref name="Strobl1893"/> * ''Delia pseudorainieri'' Griffiths, 1992 * ''Delia pseudoventralis'' (Ackland, 2008)<ref name="Ackland"/> * ''Delia quadrilateralis'' Fan & Zhong, 1982 * ''Delia quadripila'' (Stein, 1916) * ''Delia quercupinetorum'' Griffiths, 1993 * ''Delia radicum'' (Linnaeus, 1758) * ''Delia rainieri'' (Huckett, 1951) * ''Delia recurva'' (Malloch, 1919) * ''Delia recurvata'' Fan, 1986 * ''Delia reliquens'' (Huckett, 1951) * ''Delia repens'' Ackland, 1967 * ''Delia repleta'' (Huckett, 1929) * ''Delia rimiventris'' Michelsen, 2007<ref name="Michelsen2007"/> * ''Delia rossica'' Hennig, 1974 * ''Delia sanctijacobi'' (Bigot, 1885) * ''Delia saxatilis'' Griffiths, 1991 * ''Delia schistophalla'' Griffiths, 1991 * ''Delia sclerostylata'' Fan, 1993 * ''Delia scrofifacialis'' Xue & Zhang, 1996 * ''Delia segmentata'' (van der Wulp, 1896) * ''Delia sequoiae'' (Huckett, 1967) * ''Delia seriata'' (Stein, 1920) * ''Delia serrulata'' Griffiths, 1991 * ''Delia seticauda'' Suwa, 1984 * ''Delia setifirma'' (Huckett, 1951) * ''Delia setigera'' (Stein, 1920) * ''Delia setiseriata'' (Huckett, 1952) * ''Delia setisissima'' (Huckett, 1929) * ''Delia setitarsata'' (Huckett, 1924) * ''Delia setiventris'' (Stein, 1898) * ''Delia sierricola'' Griffiths, 1991 * ''Delia sileni'' Michelsen, 2012 * ''Delia silvicola'' (Robineau-Desvoidy, 1830) * ''Delia simpla'' (Coquillett, 1900) * ''Delia simpliciana'' Yudin, 1976 * ''Delia simulata'' (Huckett, 1952) * ''Delia sinuiforcipis'' Zhong, 1985 * ''Delia sobrians'' (Huckett, 1951) * ''Delia solidilamina'' Fan & Zheng, 1993 * ''Delia sphaerobasis'' Fan & Qian, 1984 * ''Delia spicularis'' Fan, 1984 * ''Delia steiniella'' (Emden, 1951) * ''Delia stenostyla'' Deng & Li, 1994 * ''Delia subalpina'' (Ringdahl, 1926) * ''Delia subatrifrons'' Xue & Du, 2009 * ''Delia subconversata'' Du & Xue, 2018<ref name="DuXue2018"/> * ''Delia subdolichosternita'' Du & Xue, 2018<ref name="DuXue2018"/> * ''Delia subinterflua'' Xue & Du, 2008<ref name="XueDu2008"/> * ''Delia submetallica'' Griffiths, 1992 * ''Delia subnemostylata'' Xue & Du, 2018 * ''Delia subnigribasis'' Fan & Wang, 1982 * ''Delia suburbana'' (Huckett, 1966) * ''Delia subvesicata'' Griffiths, 1991 * ''Delia takizawai'' Suwa, 1974 * ''Delia taonura'' Deng & Li, 1994 * ''Delia tarsata'' (Ringdahl, 1918) * ''Delia tarsifimbria'' (Pandellé, 1900) * ''Delia tenuiformis'' Suwa, 1977 * ''Delia tenuipenis'' Fan & Zhong, 1982 * ''Delia tenuiventris'' (Zetterstedt, 1860) * ''Delia terpsichore'' Griffiths, 1991 * ''Delia tibila'' Ackland, 2008<ref name="Ackland"/> * ''Delia tiensuui'' (Ringdahl, 1934) * ''Delia tornensis'' (Ringdahl, 1926) * ''Delia trispinosa'' (Karl, 1937) * ''Delia tuberisurstyla'' Xue & Du, 2017 * ''Delia tumidula'' (Ringdahl), 1949 * ''Delia turcmenica'' Hennig, 1974 * ''Delia turkestanica'' (Enderlein, 1934) * ''Delia unduliloba'' Griffiths, 1993 * ''Delia unguitigris'' Xue, 1997 * ''Delia unica'' Griffiths, 1991 * ''Delia uniseriata'' (Stein, 1914) * ''Delia unispina'' Yudin, 1976 * ''Delia urbana'' (Malloch, 1924) * ''Delia ventralis'' (Stein, 1914) * ''Delia vesicata'' (Huckett, 1952) * ''Delia virgithorax'' (Stein, 1913) * ''Delia vockerothi'' Griffiths, 1991 * ''Delia wangi'' Xue, 2018<ref name="DuXue2018"/> * ''Delia winnemana'' (Malloch, 1919) * ''Delia xanthobasis'' (Huckett, 1965) {{div col end}}

==References== {{Reflist| refs= <ref name="XueDu2008">{{cite journal|last1=Xue|first1=W.-q|last2=Du|first2=J.|title=Two new species of ''Delia'', with a key to the males of the World species of the ''interflua'' group (Diptea: Anthomyiidae)|journal=Entomological News|date=2008|volume=119|issue=2|pages=113–122|doi=10.3157/0013-872X(2008)119[113:TNSODW]2.0.CO;2|s2cid=83705076 |url=https://www.biodiversitylibrary.org/part/49725}}</ref>

<ref name="Michelsen2007">{{cite journal|last1=Michelsen|first1=Verner|title=Two new European species of Delia Robineau-Desvoidy (Diptera: Anthomyiidae) with a bipartite male sternite III|journal=Zootaxa|date=2007|volume=1469|issue=1|pages=51–57|doi=10.11646/zootaxa.1469.1.3|issn=1175-5334}}</ref>

<ref name="Ackland">{{cite journal |title=Revision of Afrotropical Delia Robineau-Desvoidy, 1830 (Diptera: Anthomyiidae), with Descriptions of six New Species |journal=African Invertebrates |date=2008 |volume=49 |issue=1 |pages=1–75 |doi=10.5733/afin.049.0101 |doi-access=free |last1=Ackland |first1=D. M. |bibcode=2008AfrIn..49....1A }}</ref>

<ref name="Strobl1893">{{cite journal|last1=Strobl|first1=Peter G.|title=Die Anthomyinen Steiermarks. (Mit Berucksichtigung der Nachbarlander.)|journal=Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien.|date=1893|volume=43|pages=213–276|doi=10.5962/bhl.part.26130|url=https://www.biodiversitylibrary.org/page/13587606#page/319/mode/1up|access-date=30 July 2017}}</ref>

<ref name="DuXue2018">{{cite journal |last1=Du |first1=J. |last2=Xue |first2=W. |title=Four new species of the genus ''Delia'' Robineau-Desvoidy, 1830 (Diptera: Anthomyiidae) from China) |journal=The Pan-Pacific Entomologist |date=2018 |volume=94 |issue=4 |pages=225–236 |doi=10.3956/2018-94.4.225 |s2cid=92845805 |issn=0031-0603}}</ref>

<ref name=catlife> {{Cite web| title=Catalogue of Life, ''Adia'' Robineau-Desvoidy, 1830 | url=https://www.catalogueoflife.org/data/taxon/BY6FP | access-date=2024-08-28 }}</ref> }}

==External links== *[https://entnemdept.ufl.edu/creatures/FIELD/CORN/seedcorn_maggot.htm ''Delia platura''] on the UF / IFAS Featured Creatures website.

Category:Anthomyiidae Category:Schizophora genera Category:Agricultural pest insects Category:Taxa named by Jean-Baptiste Robineau-Desvoidy