Some introduced species become invasive, creating serious problems in the ecosystems. Many invasive species are more successful in their new homes than in their homeland. Probably this is due to having left their natural enemies behind.
One way to combat such invasive species is to bring some of their natural enemies into the country. These are called biological controls, or biocontrols for short. The earliest insect introduced as a biocontrol was the lady beetle
Rodolia cardinalis (Vedalia Beetle) in 1888. It drastically reduced the populations of
Iceria purchasi (Cottony Cushion Scale), saving the citrus industry in California. This resounding success encouraged the use of biocontrolsr.
Since then many species have been intentionally introduced in the United States with the purpose of pest control, and the numbers keep growing. Some introductions have been as successful as the one mentioned above, others don't help much, and still others have turned into pests themselves by feeding on species other than the intended target. A disastrous example was the tachinid fly
Compsilura concinnata, introduced to control the Gypsy moth (
Lymantria dispar). It feeds on 200 species of moths and other insects, including some threatened species. Nowadays, potential biocontrols are tested thoroughly before their introduction to avoid such mistakes.
The number of introduced biocontrols is amazing, at least to me. For instance, more than 150 species of wasps have been brought for this purpose (Simberloff, Invasive Species). He adds that, in Florida, out of 1,000 established introduced insect species, 50 were introduced as biocontrols.
At least 130 introduced biocontrols are listed in BugGuide.net from the estimated several hundreds. I thought it was worth getting them all together in one place along with the invasive species they are expected to control. There seem to be comparable numbers of arthropod pest and of invasive weeds being controlled by these means. There are even a few used for dung control.
Order Hemiptera
Family Anthocoridae - Minute Pirate Bugs
*No common name, Orius insidiosus. From the Palaearctic, to control phytophagous mites and mite eggs, insect eggs, soft-bodied insects
*No common name,
Orius tristicolor. From Europe, to control mites, thrips, aphids, etc.
*No common name,
Orius vicinus. From the Palaearctic, feeds on soft bodied insects
Family Aphalaridae
*No common name,
Boreioglycaspis melaleucae. From Australia, 2002, to control
Melaleuca quinquenervia (Punktree)
Family Aphididae – Aphids
*No common name,
Aphis chloris. From Europe, 1980s, to control
Hypericum perforatum (St. John'swort)
Family Miridae - Plant Bugs
* Mullein Bug,
Campylomma verbasci. From Europe, to control aphids, mites, thrips, and pear psylla
Order Coleoptera
Family Brachyceridae
*Salvinia Weevil, Cyrtobagous salviniae. From South America via Australia 2001, to control
Salvinia molesta (Giant salvinia)
*Chevroned Waterhyacinth Weevil,
Neochetina bruchi.From S America, 1974, to control
Eichhornia crassipes (Waterhyacinth)
*Mottled water hyacinth weevil,
Neochetina eichhorniae.From S America, introduced repeatedly since 1972 to control
Eichhornia crassipes (Waterhyacinth)
*Waterlettuce Weevil,
Neohydronomus affinis. From South America, 1987, to control
Pistia stratiotes (Water Lettuce)
Family Brentidae – Straight-snouted Weevils
*Seed-feeding Weevil,
Exapion fuscirostre. From Europe, 1964, to control
Cytisus scoparius (Scotchbroom)
*Gorse Seed Weevil,
Exapion ulicis. From Europe, 1926, to control
Ulex europaeus (gorse)
*Flower Bud Weevil,
Nanophyes marmoratus. From Europe, 1994, to control
Lythrum salicaria (Purple Loosestrife)
*No common name,
Omphalapion hookerorum. From Europe, 1990, to control
Tripleurospermum perforatum (Scentless Chamomile or Scentless False Mayweed)
Family Buprestidae – Metallic Wood-boring Beetles
*St. John's Wort Root Borer,
Agrilus hyperici. From the Palaearctic, 1950, to control
Hypericum perforatum (St. John's wort)
*Bronze Knapweed Root Borer,
Sphenoptera jugoslavica. From Europe, 1980, to control
Centaurea diffusa (Bronze Knapweed)
Family Carabidae – Ground Beetles
*Caterpillar Searcher,
Calosoma sycophanta. From Europe, 1905, to control
Lymantria dispar (Gypsy Moth) and
Euproctis chrysorrhoea (Browntail Moth)
*Golden Green Beetle,
Carabus auratus. From Europe, 1940: to control
Lymantria dispar (Gypsy Moth)
Family Cerambycidae – Longhorned Beetles
*Leafy Spurge Stem Boring Beetle,
Oberea erythrocephala. From Europe, 1979, to control
Euphorbia esula (Leafy Spurge)
Family Chrysomelidae – Leaf Beetles
*Alligatorweed Flea Beetle,
Agasicles hygrophila. From Argentina and Brasil, 1964, to control
Alternanthera philoxeroides (Alligatorweed)
*Brown Dot Leafy Spurge Flea Beetle,
Aphthona cyparissiae. From Europe, 1986, to control
Euphorbia, esp.
E. cyparissias (Cypress Spurge)
*Black Leafy Spurge Flea Beetle,
Aphthona czwalinai. From Europe, 1987, to control
Euphorbia esula (Leafy Spurge)
*No common name,
Aphthona flava. From Europe, 1990s, to control
Euphorbia esula (Leafy Spurge)
*No common name,
Aphthona lacertosa. From Europe, 1990s, to control
Euphorbia cyparissias (Cypress Spurge)
*No common name,
Aphthona nigriscutis. From Europe, 1990s, to control
Euphorbia esula (Leafy Spurge)
*Broom Seed Beetle,
Bruchidius villosus. From Europe, early 1900s, to control
Cytisus scoparius (Scotch Broom)
*Thistle Tortoise Beetle,
Cassida rubiginosa. From Eurasia, 1901. Introduced accidentally. Used to control thistles
*St. Johnswort Beetle,
Chrysolina hyperici. From Eurasia, 1944 to control
Hypericum perforatum (Klamath Weed or St. John'swort)
*Klamath Weed Beetle,
Chrysolina quadrigemina. Native to Europe and N. Africa, introduced from Australia, 1944, to control
Hypericum perforatum (Klamath Weed)
*No common name,
Chrysolina varians. From Europe, to control
Hypericum (St. John'swort)
*Northern Tamarisk Beetle,
Diorhabda carinulata. From Eurasia, 2001, to control
Tamarix spp.
*Subtropical Tamarisk Beetle,
Diorhabda sublineata. From Eurasia, 2009, to control
Tamarix spp.
*Water-lily Beetle,
Galerucella nymphaeae. From Europe, to control
Nuphar spp. (Water-lilies) and
Polygonum spp. (Smartweeds)
*No common name,
Gratiana boliviana. From South America, 2003, to control
Solanum viarum (Tropical Soda Apple)
*Air Potato Leaf Beetle,
Lilioceris cheni. From Eurasia, 1912, to control
Dioscorea bulbifera (Air potato)
*No common name,
Longitarsus jacobaeae. From w. Palaearctic (Europe to Mongolia), to control
Senecio jacobaea (tansy ragwort)
*No common name,
Longitarsus quadriguttatus. From Europe,, to control
Cynoglossum officinale (Hound's-tongue)
*Black-margined Loosestrife Beetle,
Neogalerucella calmariensis. From Europe, to control
Lythrum salicaria (Purple Loosestrife)
*No common name,
Neogalerucella pusilla. From the Palaearctic, to control
Lythrum salicaria (Purple Loosestrife)
Family Coccinellidae – Lady Beetles
*Larch Ladybird,
Aphidecta obliterata. From Europe, 1960, to control
Adelges piceae (Balsam Woolly Adelgid)
*Pine Ladybird Beetle,
Brumus quadripustulatus. To control
Adelges tsugae (Hemlock Woolly Aldegid)
*Heather Lady Beetle,
Chilocorus bipustulatus. From Middle East/Europe to control scale insects, repeatedly since 1905
*Red Chilocorus,
Chilocorus circumdatus. From SE Asia, 1996, to control greenhouse pests
*No common name,
Chilocorus kuwanae. From Korea, 1980s, to control
Unaspis euonymi (Euonymus Scale)
*No common name,
Chilocorus nigrita. From Asia, to control various scale insects
*No common name,
Clitostethus arcuatus. From Israel, 1989 to control
Siphoninus phillyreae (ash whitefly) and other white flies
*Seven-spotted Lady Beetle,
Coccinella septempunctata. From Europe, introduced repeatedly to control aphids
*Variable Lady Beetle,
Coelophora inaequalis. From Australia, to control
Sipha flava (Yellow Sugarcane Aphid)
*No common name,
Cryptognatha nodiceps. From Trinidad, 1930s to control
Aspidiotus destructor (Coconut Scale)
*Mealybug Destroyer,
Cryptolaemus montrouzieri. From Australia, 1891 to control citrus mealybugs and related pests
*Metallic Blue Ladybird Beetle,
Curinus coeruleus. From the Caribean, 2013, repeatedly introduced to control
Diaphorina citri (Asian Citrus Psyllid) and scale insects and aphids
*No common name,
Exochomus metallicus. From Eritrea in 1954. To control citricola and black scales. Attacks
Planococcus citri (Citrus Mealybug)
*Steelblue Lady Beetle,
Halmus chalybeus. From Australia, recently 2000s? To control scale insects
*Multicolored Asian Lady Beetle,
Harmonia axyridis. From Asia, introduced repeatedly starting in 1916 to control aphids, thrips, mites, scale insects, and eggs of butterflies and moths
*No common name,
Harmonia dimidiata. To control
Aphis spiraecola (Spirea Aphid)
*Fourteen-spotted Lady Beetle,
Propylea quatuordecimpunctata. From Europe to control
Diuraphis noxia (Russian Wheat Aphid))
*No common name,
Rhyzobius forestieri. From Australia, 1892, to control scale insects
*No common name,
Rhyzobius lophanthae. From Australia, 1892, to control
Saissetia oleae (Black Scale)
*Vedalia Lady Beetle,
Rodolia cardinalis. From Australia, 1888-1889, to control
Icerya purchasi (Cottony Cushion Scale)
*No common name,
Sasajiscymnus tsugae. From Japan, 1995 to control
Adelges tsugae (Hemlock Woolly Adelgid)
*No common name,
Scymnus impexus. From Europe, 1951 to control
Adelges piceae (Balsam Woolly Adelgid)
*No common name,
Scymnus suturalis. From the Palaearctic, early 1900s to control
Adelges tsugae (Hemlock Woolly Adelgid)
*No common name,
Stethorus punctillum. From the Palaearctic, to control spider mites, 1955
Family Curculionidae – Snout and Bark Beetles
*Yellow Starthistle Bud Weevil,
Bangasternus orientalis. From Europe, 1985, to control
Centaurea solstitialis (Yellow Starthistle)
*Large Thistle Weevil,
Cleonis piger. From Europe, before 1919, to control thistles
*Knapweed Root Weevil,
Cyphocleonus achates. From Europe, 1980s, to control Centaurea (Knapweed)
*Yellow Starthistle Hairy Weevil,
Eustenopus villosus. From Europe, 1990 to control
Centaurea solstitialis (Yellow Starthistle),
Cirsium arvense (Canada Thistle)
*Canadian Thistle Stem Weevil,
Hadroplontus litura. From Europe, 1965, to control
Cirsium arvense (Canada Thistle)
*Root-feeding Weevil,
Hylobius transversovittatus. From Europe, 1992, to control
Lythrum salicaria (Purple Loosestrife)
*No common name,
Hypera rumicis. From Europe, to control
Rumex
*Yellow star thistle flower weevil,
Larinus curtus. From the Mediterranean and Asia. 1992, to control
Centaurea solstitialis (Yellow Starthistle)
*Seedhead Weevil,
Larinus minutus. From Europe, 1991, to control
Centaurea maculosa (Spotted Knapweed) and
C. diffusa (Diffuse Knapweed )
*Canada Thistle Bud Weevil,
Larinus planus. From Europe, 1960s, to control
Cirsium arvense (Canada Thistle)
*Knapweed Seedhead Weevil,
Larinus obtusus. From South and Central Europe, 1993, to control
Centaurea (Knapweeds)
*No common name,
Larinus turbinatus. From Europe, very recently (2010s?), to control thistles (
Carduus and
Cirsium)
*Stem-boring Weevil,
Mecinus janthinus. From Europe, 1991, to control
Linaria spp. (toadflax)
*No common name,
Mecinus pascuorum. From Europe, 1956, to control
Plantago lanceolata (plantain)
*Puncturevine Seed Weevil,
Microlarinus lareynii. From Europe, 1960s to control
Tribulus terrestris (Puncturevine)
*Puncturevine Stem Weevil,
Microlarinus lypriformis. From India, 1961 to control
Tribulus terrestris (Puncturevine)
*No common name,
Microplontus edentulus. From Europe, to control
Matricaria perforata (Scentless Chamomile)
*Hound's-tongue Root Weevil,
Mogulones crucifer. From Europe, 1997, to control
Cynoglossum officinale (Hound's Tongue)
*Melaleuca Leaf Weevil,
Oxyops vitiosa. From Australia, 1997, to control
Melaleuca (paper bark tree)
*Mediterranean Sage Root Crown Weevil,
Phrydiuchus tau. From Europe, 1971, to control
Salvia aethiopis (Mediterranean Sage Root)
*Thistle Head Weevil,
Rhinocyllus conicus. From the Mediterranean and the Middle East, 1968, to control
Carduus nutans (Musk Thistle)
*Mile-a-minute Weevil,
Rhinoncomimus latipes. From China, 2004, to control
Persicaria perfoliata (Mile-a-minute)
*Toadflax Seedhead Weevil,
Rhinusa antirrhini. From Europe, to control
Linaria spp. (yellow and Dalmatian toadflax)
No common name,
Rhinusa asellus. From Europe to control
Verbascum
*Root-gall Weevil,
Rhinusa linariae. From Europe, 1995, to control
Linaria spp. (yellow and Dalmatian toadflax)
*No common name,
Rhinusa neta. From Europe, 1937, to control
Linaria spp. (yellow and Dalmatian toadflax)
*European Curculionid Weevil,
Rhinusa tetra. From Europe, earlier than 1916, to control
Verbascum (Common Mullein) and
and Scrophularia
*Thistle Crown Weevil,
Trichosirocalus horridus. From Europe, in 1970-1972, to control thistles
Family Derodontidae – Tooth-necked Fungus Beetles
*No common name,
Laricobius erichsoni.From Europe, 1951, to control
Cinara spp. and related conifer aphids
Family Kateretidae – Short-winged Flower Beetles
*Toadflax Flower-eating Beetle,
Brachypterolus pulicarius. From Europe, before 1920, to control
Linaria (Toadflax)
Family Nitidulidae – Sap-feeding Beetles
*No common name,
Cybocephalus nipponicus. From China/Korea, recently, repeatedly introduced to control armored scale insects (
Diaspididae)
Family Scarabaeidae – Scarab Beetles
*Gazelle Scarab,
Digitonthophagus gazella. From Africa/Asia. 1970s for dung removal
*No common name,
Euoniticellus intermedius. From Africa, intentionally introduced for dung removal
Order Hymenoptera
Family Aphelinidae
*No common name, Aphytis spp. From East Asia to control
Aonidiella aurantii (Red Scale) and other scales
Family Bethylidae
*Navel Orangeworm Wasp,
Goniozus legneri. From South America, to control
Amyelois transitella (Navel Orangeworm),
Cydia pomonella (codling moth),
Ectomyelois ceratoniae (Carob Moth), and others
Family Crabronidae
*Mole Cricket Hunter,
Larra bicolor. From Bolivia, 1988-89, to control
Scapteriscus spp. mole crickets
Family Encyrtidae – Encyrtids
*No common name,
Neodusmetia sangwani. From India, 1971, to control Rhodesgrass mealybug (
Antonina graminis )
*No common name,
Oobius agrili. From China, recently, to control
Agrilus planipennis (Emerald Ash Borer)
*No common name,
Ooencyrtus kuvanae. From Japan, early 1990s, to control
Lymantria dispar (gypsy moth)
*No common name,
Psyllaephagus spp. From Australia, 3 spp. to control Psyllids
*No common name,
Psyllaephagus bliteus. From Australia, 1998, to control
Glycaspis brimblecombei (Red Gum Lerp Psyllid)
*No common name,
Tachinaephagus zealandicus. From Australia, 1967, to control Muscoid flies
*No common name,
Tetracnemoidea sydneyensis. From Australia, 1933, to control
Pseudococcus longispinus (Long-tailed Mealybug) and other
Pseudococcus spp.
Family Ichneumonidae – Ichneumon Wasps
*No common name,
Aptesis nigrocincta. From the Palaearctic, to control
Hoplocampa testudinea (European apple sawfly) and
Caliroa cerasi (Pear Slug Sawfly)
*No common name,
Bathyplectes curculionis. From the Palaearctic, 1911, to control the
Hypera postica (Alfalfa Leaf Weevil)
*No common name,
Bathyplectes infernalis. From the Palaearctic to control
Donus zoilus (Clover Leaf Weevil)
*No common name,
Collyria coxator. From the Palaearctic, to control Cephidae
Cephus pygmaeus,
Janus integer
*No common name,
Eriborus terebrans. From the Palaearctic, from 1927 through 1940, to control
Ostrinia nubilalis (European Corn Borer)
*No common name,
Exenterus amictorius. From Europe, to control
Diprion similis (Introduced Pine Sawfly)
*No common name,
Lemophagus curtus. From the Palaearctic, 1969 and 1971, to control
Oulema melanopus (Cereal Leaf Beetle)
*No common name,
Mesoleius tenthredinis. From the Palaearctic, to control
Pristiphora erichsonii (Larch Sawfly)
*No common name,
Neotypus nobilitator. From the Palaearctic to control (?)
*No common name,
Olesicampe benefactor. From Europe, to control
Pristiphora erichsonii (Larch Sawfly)
*No common name,
Phaeogenes nigridens. From the Palaearctic, to control
Ostrinia nubilalis (European Corn Borer)
*No common name,
Phobocampe unicincta. From the Palaearctic, to control
Lymantria dispar (gypsy moth)
*No common name,
Pimpla instigator. Probably from W Palaearctic, to control
Lymantria dispar (gypsy moth)
*No common name,
Pimpla turionellae. From the Palaearctic, to control
Cydia pomonella (Codling Moth)
*No common name,
Pleolophus basizonus. From the Palaearctic, to control
Neodiprion sawflies
*No common name,
Temelucha interruptor. From the Palaearctic, to control
Rhyacionia buoliana (European Pine Shoot Moth)
Family Tiphiidae – Tiphiid Wasps
*Spring tiphia,
Tiphia vernalis. From Korea and China, 1925. to control
Popillia japonica (Japanese beetle)
Order Lepidoptera
Family Coleophoridae – Casebearer Moths
*Russian Thistle Stem Miner Moth, Coleophora parthenica. From the Mediterranean region to control
Salsola tragus (Russian Thistle)
Family Crambidae – Crambid Snout Moths
*Water Veneer,
Acentria ephemerella. From Eurasia, 1920s, to control
Myriophyllum spicatum (Eurasian Watermilfoil)
*Water Hyacinth Moth,
Niphograpta albiguttalis. From South America, 1977 to control
Eichhornia crassipes (Waterhyacinth)
Family Depressariidae
*Poison Hemlock Moth,
Agonopterix alstroemeriana. From Europe, 1970s, to control
Conium maculatum (Poison Hemlock)
*Gorse Tip Moth,
Agonopterix nervosa. From Europe, to control
Ulex europaeus (Gorse)
Family Erebidae
*Cinnabar Moth,
Tyria jacobaeae. From Europe, 1960s to control
Senecio jacobaea (Tansy Ragwort)
Family Gelechiidae – Twirler Moths
*Spotted knapweed seed head moth,
Metzneria paucipunctella. From the Palaearctic, 1980s, to control
Centaurea spp. (Knapweed)
Family Geometridae – Geometrid Moths
*Treble-bar,
Aplocera plagiata. From Europe, 1976, to control
Hypericum perforatum (St. John'swort)
Family Noctuidae – Owlet Moths
*Toadflax Brocade,
Calophasia lunula. From Palaearctic, to control
Linaria spp. (yellow and Dalmatian toadflax)
Family Pyralidae – Pyralid Moths
*Alligatorweed Stem Borer Moth,
Macrorrhinia endonephele. From South America, 1972, to control alligatorweed
Family Sesiidae – Clearwing Moths
*No common name,
Chamaesphecia empiformis. From Europe, 1970s, to control
Euphorbia cyparissias (Cypress Spurge)
Family Sphingidae – Sphinx Moths
*Spurge Hawkmoth,
Hyles euphorbiae. From Europe, to control
Euphorbia esula (Leafy Spurge)
Family Tortricidae – Tortricid Moths
*Sulphur Knapweed Moth,
Agapeta zoegana. From Europe, 1984, to control
Centaurea (Knapweed)
Order Diptera
Family Cecidomyiidae - Gall Midges
*Skeleton gall midge, Cystiphora schmidti. From Greece, to control
Chondrilla juncea (rush skeletonweed)
*No common name,
Cystiphora sonchi. From Europe, to control
Sonchus (Sow-thistle)
Family Cryptochaetidae - Scale Parasite Flies
*Cottony Cushion Scale Parasite,
Cryptochaetum iceryae. From Australia, 1888 or 1889 to control
Icerya purchasi (Cottony Cushion Scale)
Family Phoridae - Scuttle Flies
*No common name,
Pseudacteon tricuspis and spp. From South America 1997, to control
Solenopsis invicta (Red Imported Fire Ant)
Family Syrphidae - Syrphid Flies
*No common name,
Cheilosia grossa. From Europe, to control thistles
Family Tachinidae
*No common name,
Compsilura concinnata. From Europe, 1906 to control
Lymantria dispar (Gypsy Moth)
*No common name,
Exorista larvarum. From Europe, to control
Lymantria dispar (Gypsy Moth)
*Winsome Fly,
Istocheta aldrichi. From Asia, 1922, to control
Popillia japonica (Japanese beetle)
*No common name,
Triarthria setipennis. From Europe, 1920s, to control
Forficula auricularia (European earwig)
333800
Family Tephritidae - Fruit Flies
*Yellow Starthistle Peacock Fly,
Chaetorellia australis. From Europe, 1988, to control thistles
*No common name,
Terellia fuscicornis. From Europe to combat thistles
*No common name,
Terellia ruficauda. From Europe to combat thistles
*No common name,
Urophora affinis. From Europe, 1971, to control
Centaurea (Knapweeds)
*No common name,
Urophora cardui. From Europe, to control
Cirsium arvense (Canada Thistle)
*Brown Knapweed Gall Fly,
Urophora jaceana. From Europe, to control
Centaurea (Knapweeds)
*No common name,
Urophora quadrifasciata. From Europe, 1988, to control
Centaurea (Knapweeds)
*Yellow Starthistle Gall Fly,
Urophora sirunaseva. From Europe, to control
Centaurea solstitialis (Yellow Starthistle)
*Bull Thistle Gall Fly,
Urophora stylata. From Europe, 1973, to control
Cirsium vulgare (Bull Thistle)
Order Opiliones – Harvestmen
Family Phalangiidae
*No common name,
Phalangium opilio. From the Palaearctic, feeds on aphids, caterpillars, leafhoppers, beetle larvae, mites, and small slugs
Order Mesostigmata
Family Eriophyidae
*Skeletonweed Gall Mite, Aceria chondrillae. From Europe, to control
Chondrilla juncea (Skeletonweed)
*Lantana Flower Gall Mite,
Aceria lantanae. From Central and South America, to control
Lantana camara
*No common name,
Aculops ailanthii. From Asia, to control
Ailanthus altissima
Family Phytoseiidae
*No common name,
Amblyseius swirskii From the Mediterranean to control
Thysanoptera (Thrips) and
Trialeurodes vaporariorum (Greenhouse Whitefly)
Further Readings
Biological Control Journal
Biological control. Chapter 4
Biocontrol Agents Available for Redistribution. British Columbia. Ministry of Forests, Lands and Natural Resource Operations
Biological Control. Cornell U.
Oregon State U. Biological Pest Controls
Washington State U. Biological Control Agents - By Insect
At least 16 species of Tachinidae have been introduced as biological controls (
Grenier 1988)
This is a work in progress. I intend to add some links and references. I gladly accept any help. I am sure that there are some typos as well as more serious problems and I know I can count on BugGuide contributors. Thanks in advance.