Biological Control Agents and Their Roles

Biocontrol Agent	Role	Weed Species
Aceria chondrillae (formerly Eriophyes chondrillae)	bud gall mite	Skeletonweed, rush (Chondrilla juncea)
Aceria drabae F	gall mite	Whitetop or hoary cress (Lepidium draba)
Aceria malherbae	bud/leaf gall mite	Bindweed, field (Convolvulus arvensis)
Agapeta zoegana	root-boring moth	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos; knapweed, diffuse (Centaurea diffusa)
Agonopterix alstroemeriana	defoliating moth	Hemlock, poison (Conium maculatum)
Agrilus hyperici	root-boring beetle	St. Johnswort (Hypericum perforatum)
Aphalara itadori F – Hokkaido (northern) strain	sap-sucking psyllid	Knotweed, giant (Reynoutria sachalinensis; = Polygonum sachalinense; = Fallopia sachalinensis)
Aphalara itadori F – Kyushu (southern) strain	sap-sucking psyllid	Knotweed, Japanese (Reynoutria japonica; = Polygonum cuspidatum; = Fallopia japonica); Bohemian (Reynoutria x bohemica; = Polygonum x bohemicum; = Fallopia x bohemica)
Aphthona cyparissiae	root/defoliating flea beetle	Spurge, leafy (Euphorbia virgata; = E. esula)
Aphthona czwalinai	root/defoliating flea beetle	Spurge, leafy (Euphorbia virgata; = E. esula)
Aphthona flava	root/defoliating flea beetle	Spurge, leafy (Euphorbia virgata; = E. esula)
Aphthona lacertosa	root/defoliating flea beetle	Spurge, leafy (Euphorbia virgata; = E. esula)
Aphthona nigriscutis	root/defoliating flea beetle	Spurge, leafy (Euphorbia virgata; = E. esula)
Aplocera plagiata	defoliating moth	St. Johnswort (Hypericum perforatum)
Aulacidea acroptilonica	gall wasp	Knapweed, Russian (Rhaponticum repens; = Acroptilon repens)
Aulacidea subterminalis F	gall wasp	Hawkweeds (mouse-ear [Pilosella officinarum]; orange [P. aurantiaca]; whiplash [P. flagellaris])
Bangasternus fausti	seed head weevil	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)
Bangasternus orientalis	seed head weevil	Starthistle, yellow (Centaurea solstitialis)
Botanophila seneciella	seed head fly	Ragwort, tansy (Jacobaea vulgaris; = Senecio jacobaea)
Brachypterolus pulicarius	flower beetle	Toadflax, yellow (Linaria vulgaris); toadflax, Dalmatian (L. dalmatica)
Bradyrrhoa gilveolella	root-boring moth	Skeletonweed, rush (Chondrilla juncea)
Bruchidius villosus	seed beetle	Broom, Scotch (Cytisus scoparius); broom, French (Genista monspessulana)
Calophasia lunula	defoliating moth	Toadflax, Dalmatian (L. dalmatica); toadflax, yellow (Linaria vulgaris)
Ceratapion basicorne F	root crown weevil	Starthistle, yellow (Centaurea solstitialis)
Chaetorellia acrolophi	seed head fly	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos)
Chaetorellia australis	seed head fly	Starthistle, yellow (Centaurea solstitialis)
Cheilosia grossa (formerly C. corydon)	stem fly	Thistle, slenderflower (Carduus tenuiflorus); thistle, Italian (C. pycnocephalus); thistle, bull (Cirsium vulgare); thistle, musk (Carduus nutans)
Cheilosia urbana F	root-boring fly	Hawkweeds (Pilosella aurantiaca, P. caespitosa, P. flagellaris, P. floribunda, P. glomerata, P. officinarum, P. piloselloides)
Chrysolina hyperici	defoliating beetle	St. Johnswort (Hypericum perforatum)
Chrysolina quadrigemina	defoliating beetle	St. Johnswort (Hypericum perforatum)
Cyphocleonus achates	root-boring/gall weevil	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)
Cystiphora schmidti	stem/leaf gall midge	Skeletonweed, rush (Chondrilla juncea)
Diorhabda spp. C	leaf beetle	Saltcedar (Tamarix chinensis, T. parviflora, T. ramosissima)
Euhrychiopsis lecontei E	stem weevil	Watermilfoil, Eurasian (Myriophyllum spicatum)
Eustenopus villosus	seed head weevil	Starthistle, yellow (Centaurea solstitialis)
Exapion fuscirostre	seed weevil	Broom, Scotch (Cytisus scoparius)
Exapion ulicis	seed weevil	Gorse (Ulex europaeus)
Galerucella calmariensis	leaf beetle	Loosestrife, purple (Lythrum salicaria)
Galerucella pusilla	leaf beetle	Loosestrife, purple (Lythrum salicaria)
Hadroplontus litura (formerly Ceutorhynchus litura)	crown/stem-mining weevil	Thistle, Canada (Cirsium arvense)
Hyles euphorbiae	defoliating moth	Spurge, leafy (Euphorbia virgata; = E. esula)
Hylobius transversovittatus	root-boring weevil	Loosestrife, purple (Lythrum salicaria)
Jaapiella ivannikovi	shoot tip gall midge	Knapweed, Russian (Rhaponticum repens; = Acroptilon repens)
Larinus curtus D	seed head weevil	Starthistle, yellow (Centaurea solstitialis)
Larinus minutus	seed head weevil	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, meadow (C. debeauxii subsp. grandiflora; C. jacea nothosubsp. pratensis)); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)
Larinus obtusus	seed head weevil	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, meadow (C. debeauxii subsp. grandiflora; C. jacea nothosubsp. pratensis)
Leucoptera spartifoliella	twig mining moth	Broom, Scotch (Cytisus scoparius)
Longitarsus jacobaeae	root/defoliating flea beetle	Ragwort, tansy (Jacobaea vulgaris; = Senecio jacobaea)
Mecinus janthiniformis (formerly M. janthinus)	stem-boring weevil	Toadflax, Dalmatian (Linaria dalmatica)
Mecinus janthinus	stem-boring weevil	Toadflax, yellow (Linaria vulgaris)
Mesoanguina picridis (formerly Subanguina picridis)	stem/leaf gall nematode	Knapweed, Russian (Rhaponticum repens; = Acroptilon repens)
Metzneria paucipunctella	seed head moth	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, diffuse (C. diffusa)
Microlarinus lareynii G	seed weevil	Puncturevine (Tribulus terrestris)
Microlarinus lypriformis G	stem weevil	Puncturevine (Tribulus terrestris)
Nanophyes marmoratus	flower bud weevil	Loosestrife, purple (Lythrum salicaria)
Oberea erythrocephala	stem-boring beetle	Spurge, leafy (Euphorbia virgata; = E. esula)
Phrydiuchus tau	crown/root weevil	Sage, Mediterranean (Salvia aethiopis)
Pterolonche inspersa	root-boring moth	Knapweed, diffuse (Centaurea diffusa)
Puccinia chondrillina H	rust fungus	Skeletonweed, rush (Chondrilla juncea)
Puccinia jacea var. solstitialis H	rust fungus	Starthistle, yellow (Centaurea solstitialis)
Puccinia punctiformis H	rust fungus	Thistle, Canada (Cirsium arvense)
Ramularia crupinae H	fungus	Crupina, common (Crupina vulgaris)
Rhinocyllus conicus A	seed head weevil	Thistle, slenderflower (Carduus tenuiflorus); thistle, plumeless (C. acanthoides); thistle, musk (C. nutans); thistle, milk (Silybum marianum); thistle, Italian (C. pycnocephalus); thistle, Canada (Cirsium arvense)
Rhinusa spp.	seed head weevil	Toadflax, Dalmatian (L. dalmatica); toadflax, yellow (Linaria vulgaris)
Rhinusa pilosa F	shoot-galling weevil	Toadflax, yellow (Linaria vulgaris)
Sericothrips staphylinus F	leaf thrips	Gorse (Ulex europaeus)
Sphenoptera jugoslavica	root-boring/gall beetle	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)
Terellia virens	seed head fly	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos)
Tetranychus lintearius	spider mite	Gorse (Ulex europaeus)
Trichosirocalus horridus A	root/crown weevil	Thistle, slenderflower (Carduus tenuiflorus); thistle, plumeless (C. acanthoides); thistle, musk (C. nutans); thistle, Italian (C. pycnocephalus); thistle, bull (Cirsium vulgare)
Tyria jacobaeae B	defoliating moth	Ragwort, tansy (Jacobaea vulgaris; = Senecio jacobaea)
Tyta luctuosa	defoliating moth	Bindweed, field (Convolvulus arvensis)
Urophora affinis	seed head gall fly	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)
Urophora cardui	stem gall fly	Thistle, Canada (Cirsium arvense)
Urophora quadrifasciata	seed head gall fly	Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, meadow (C. debeauxii subsp. grandiflora; C. jacea nothosubsp. pratensis); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)
Urophora sirunaseva	seed head gall fly	Starthistle, yellow (Centaurea solstitialis)
Urophora stylata	seed head gall fly	Thistle, bull (Cirsium vulgare)
A Rhinocyllus conicus and Trichosirocalus horridus are not recommended. They attack native thistles and interstate permits are suspended. B Tyria jacobaeae is not recommended east of the Cascades, particularly in Idaho. It attacks several native plant species. C Interstate permits are suspended for Diorhabda spp. D Larinus curtus may be infected with a disease that can reduce insect populations. It should not be redistributed to avoid spreading the disease to healthy L. curtus populations. E Euhrychiopsis lecontei is a native insect, and thus, not a classical biological control agent. The weevil is co-evolved with native milfoil, Myriophyllum sibiricum, but also attacks Eurasian watermilfoil, M. spicatum. It is naturally-occurring at many lakes in the Pacific Northwest but is not currently available for redistribution. F Aceria drabae, Aphalara itadori, Aulacidea subterminalis, Ceratapion basicorne, Cheilosia urbana, Rhinusa pilosa, and Sericothrips staphylinus are new biocontrol agents that are still undergoing testing and establishment. It is unclear when they will be available for widespread distribution or how effective they will be on their host plant. G Puncturevine weevils (Microlarinus lareynii and M. lypriformis) cannot survive cold winters in the Pacific Northwest and do not sustain large enough populations to provide adequate control. H Special research permits are currently required for all pathogen biocontrol agent distribution. It is illegal to redistribute pathogens, both inter- and intrastate, without a permit.

Aceria chondrillae (formerly Eriophyes chondrillae)

bud gall mite

Skeletonweed, rush (Chondrilla juncea)

Aceria drabae F

gall mite

Whitetop or hoary cress (Lepidium draba)

Aceria malherbae

bud/leaf gall mite

Bindweed, field (Convolvulus arvensis)

Agapeta zoegana

root-boring moth

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos; knapweed, diffuse (Centaurea diffusa)

Agonopterix alstroemeriana

defoliating moth

Hemlock, poison (Conium maculatum)

Agrilus hyperici

root-boring beetle

St. Johnswort (Hypericum perforatum)

Aphalara itadori F – Hokkaido (northern) strain

sap-sucking psyllid

Knotweed, giant (Reynoutria sachalinensis; = Polygonum sachalinense; = Fallopia sachalinensis)

Aphalara itadori F – Kyushu (southern) strain

sap-sucking psyllid

Knotweed, Japanese (Reynoutria japonica; = Polygonum cuspidatum; = Fallopia japonica); Bohemian (Reynoutria x bohemica; = Polygonum x bohemicum; = Fallopia x bohemica)

Aphthona cyparissiae

root/defoliating flea beetle

Spurge, leafy (Euphorbia virgata; = E. esula)

Aphthona czwalinai

root/defoliating flea beetle

Spurge, leafy (Euphorbia virgata; = E. esula)

Aphthona flava

root/defoliating flea beetle

Spurge, leafy (Euphorbia virgata; = E. esula)

Aphthona lacertosa

root/defoliating flea beetle

Spurge, leafy (Euphorbia virgata; = E. esula)

Aphthona nigriscutis

root/defoliating flea beetle

Spurge, leafy (Euphorbia virgata; = E. esula)

Aplocera plagiata

defoliating moth

St. Johnswort (Hypericum perforatum)

Aulacidea acroptilonica

gall wasp

Knapweed, Russian (Rhaponticum repens; = Acroptilon repens)

Aulacidea subterminalis F

gall wasp

Hawkweeds (mouse-ear [Pilosella officinarum]; orange [P. aurantiaca]; whiplash [P. flagellaris])

Bangasternus fausti

seed head weevil

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)

Bangasternus orientalis

seed head weevil

Starthistle, yellow (Centaurea solstitialis)

Botanophila seneciella

seed head fly

Ragwort, tansy (Jacobaea vulgaris; = Senecio jacobaea)

Brachypterolus pulicarius

flower beetle

Toadflax, yellow (Linaria vulgaris); toadflax,
Dalmatian (L. dalmatica)

Bradyrrhoa gilveolella

root-boring moth

Skeletonweed, rush (Chondrilla juncea)

Bruchidius villosus

seed beetle

Broom, Scotch (Cytisus scoparius); broom, French (Genista monspessulana)

Calophasia lunula

defoliating moth

Toadflax, Dalmatian (L. dalmatica); toadflax, yellow (Linaria vulgaris)

Ceratapion basicorne F

root crown weevil

Starthistle, yellow (Centaurea solstitialis)

Chaetorellia acrolophi

seed head fly

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos)

Chaetorellia australis

seed head fly

Starthistle, yellow (Centaurea solstitialis)

Cheilosia grossa (formerly C. corydon)

stem fly

Thistle, slenderflower (Carduus tenuiflorus); thistle, Italian (C. pycnocephalus); thistle, bull (Cirsium vulgare); thistle, musk (Carduus nutans)

Cheilosia urbana F

root-boring fly

Hawkweeds (Pilosella aurantiaca, P. caespitosa, P. flagellaris, P. floribunda, P. glomerata, P. officinarum, P. piloselloides)

Chrysolina hyperici

defoliating beetle

St. Johnswort (Hypericum perforatum)

Chrysolina quadrigemina

defoliating beetle

St. Johnswort (Hypericum perforatum)

Cyphocleonus achates

root-boring/gall weevil

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)

Cystiphora schmidti

stem/leaf gall midge

Skeletonweed, rush (Chondrilla juncea)

Diorhabda spp. C

leaf beetle

Saltcedar (Tamarix chinensis, T. parviflora, T. ramosissima)

Euhrychiopsis lecontei E

stem weevil

Watermilfoil, Eurasian (Myriophyllum spicatum)

Eustenopus villosus

seed head weevil

Starthistle, yellow (Centaurea solstitialis)

Exapion fuscirostre

seed weevil

Broom, Scotch (Cytisus scoparius)

Exapion ulicis

seed weevil

Gorse (Ulex europaeus)

Galerucella calmariensis

leaf beetle

Loosestrife, purple (Lythrum salicaria)

Galerucella pusilla

leaf beetle

Loosestrife, purple (Lythrum salicaria)

Hadroplontus litura (formerly Ceutorhynchus litura)

crown/stem-mining weevil

Thistle, Canada (Cirsium arvense)

Hyles euphorbiae

defoliating moth

Spurge, leafy (Euphorbia virgata; = E. esula)

Hylobius transversovittatus

root-boring weevil

Loosestrife, purple (Lythrum salicaria)

Jaapiella ivannikovi

shoot tip gall midge

Knapweed, Russian (Rhaponticum repens; = Acroptilon repens)

Larinus curtus D

seed head weevil

Starthistle, yellow (Centaurea solstitialis)

Larinus minutus

seed head weevil

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, meadow (C. debeauxii subsp. grandiflora; C. jacea nothosubsp. pratensis)); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)

Larinus obtusus

seed head weevil

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, meadow (C. debeauxii subsp. grandiflora; C. jacea nothosubsp. pratensis)

Leucoptera spartifoliella

twig mining moth

Broom, Scotch (Cytisus scoparius)

Longitarsus jacobaeae

root/defoliating flea beetle

Ragwort, tansy (Jacobaea vulgaris; = Senecio jacobaea)

Mecinus janthiniformis (formerly M. janthinus)

stem-boring weevil

Toadflax, Dalmatian (Linaria dalmatica)

Mecinus janthinus

stem-boring weevil

Toadflax, yellow (Linaria vulgaris)

Mesoanguina picridis (formerly Subanguina picridis)

stem/leaf gall nematode

Knapweed, Russian (Rhaponticum repens; = Acroptilon repens)

Metzneria paucipunctella

seed head moth

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, diffuse (C. diffusa)

Microlarinus lareynii G

seed weevil

Puncturevine (Tribulus terrestris)

Microlarinus lypriformis G

stem weevil

Puncturevine (Tribulus terrestris)

Nanophyes marmoratus

flower bud weevil

Loosestrife, purple (Lythrum salicaria)

Oberea erythrocephala

stem-boring beetle

Spurge, leafy (Euphorbia virgata; = E. esula)

Phrydiuchus tau

crown/root weevil

Sage, Mediterranean (Salvia aethiopis)

Pterolonche inspersa

root-boring moth

Knapweed, diffuse (Centaurea diffusa)

Puccinia chondrillina H

rust fungus

Skeletonweed, rush (Chondrilla juncea)

Puccinia jacea var. solstitialis H

rust fungus

Starthistle, yellow (Centaurea solstitialis)

Puccinia punctiformis H

rust fungus

Thistle, Canada (Cirsium arvense)

Ramularia crupinae H

fungus

Crupina, common (Crupina vulgaris)

Rhinocyllus conicus A

seed head weevil

Thistle, slenderflower (Carduus tenuiflorus); thistle, plumeless (C. acanthoides); thistle, musk (C. nutans); thistle, milk (Silybum marianum); thistle, Italian (C. pycnocephalus); thistle, Canada (Cirsium arvense)

Rhinusa spp.

seed head weevil

Toadflax, Dalmatian (L. dalmatica); toadflax, yellow (Linaria vulgaris)

Rhinusa pilosa F

shoot-galling weevil

Toadflax, yellow (Linaria vulgaris)

Sericothrips staphylinus F

leaf thrips

Gorse (Ulex europaeus)

Sphenoptera jugoslavica

root-boring/gall beetle

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)

Terellia virens

seed head fly

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos)

Tetranychus lintearius

spider mite

Gorse (Ulex europaeus)

Trichosirocalus horridus A

root/crown weevil

Thistle, slenderflower (Carduus tenuiflorus); thistle, plumeless (C. acanthoides); thistle, musk (C. nutans); thistle, Italian (C. pycnocephalus); thistle, bull (Cirsium vulgare)

Tyria jacobaeae B

defoliating moth

Ragwort, tansy (Jacobaea vulgaris; = Senecio jacobaea)

Tyta luctuosa

defoliating moth

Bindweed, field (Convolvulus arvensis)

Urophora affinis

seed head gall fly

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)

Urophora cardui

stem gall fly

Thistle, Canada (Cirsium arvense)

Urophora quadrifasciata

seed head gall fly

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, meadow (C. debeauxii subsp. grandiflora; C. jacea nothosubsp. pratensis); knapweed, diffuse (C. diffusa); knapweed, squarrose (Centaurea virgata subsp. squarrosa)

Urophora sirunaseva

seed head gall fly

Starthistle, yellow (Centaurea solstitialis)

Urophora stylata

seed head gall fly

Thistle, bull (Cirsium vulgare)

A Rhinocyllus conicus and Trichosirocalus horridus are not recommended. They attack native thistles and interstate permits are suspended.

B Tyria jacobaeae is not recommended east of the Cascades, particularly in Idaho. It attacks several native plant species.

C Interstate permits are suspended for Diorhabda spp.

D Larinus curtus may be infected with a disease that can reduce insect populations. It should not be redistributed to avoid spreading the disease to healthy L. curtus populations.

E Euhrychiopsis lecontei is a native insect, and thus, not a classical biological control agent. The weevil is co-evolved with native milfoil, Myriophyllum sibiricum, but also attacks Eurasian watermilfoil, M. spicatum. It is naturally-occurring at many lakes in the Pacific Northwest but is not currently available for redistribution.

F Aceria drabae, Aphalara itadori, Aulacidea subterminalis, Ceratapion basicorne, Cheilosia urbana, Rhinusa pilosa, and Sericothrips staphylinus are new biocontrol agents that are still undergoing testing and establishment. It is unclear when they will be available for widespread distribution or how effective they will be on their host plant.

G Puncturevine weevils (Microlarinus lareynii and M. lypriformis) cannot survive cold winters in the Pacific Northwest and do not sustain large enough populations to provide adequate control.

H Special research permits are currently required for all pathogen biocontrol agent distribution. It is illegal to redistribute pathogens, both inter- and intrastate, without a permit.