Biological Control Agents and Their Roles

Revised: 
March 2017

Classical biological control agents introduced into the Pacific Northwest for the management of weeds and the general role of each biocontrol species.

Biocontrol Agent

Role

Weed Species

Aceria chondrillae (formerly Eriophyes chondrillae)

bud gall mite

Skeletonweed, rush (Chondrilla juncea)

Aceria malherbae

bud/leaf gall mite

Bindweed, field (Convolvulus arvensis)

Agapeta zoegana

root-boring moth

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

Agrilus hyperici

root-boring beetle

St. Johnswort (Hypericum perforatum)

Aplocera plagiata

defoliating moth

St. Johnswort (Hypericum perforatum)

Aphthona cyparissiae

root/defoliating flea beetle

Spurge, leafy (Euphorbia esula)

Aphthona czwalinai

root/defoliating flea beetle

Spurge, leafy (Euphorbia esula)

Aphthona flava

root/defoliating flea beetle

Spurge, leafy (Euphorbia esula)

Aphthona lacertosa

root/defoliating flea beetle

Spurge, leafy (Euphorbia esula)

Aphthona nigriscutis

root/defoliating flea beetle

Spurge, leafy (Euphorbia esula)

Aulacidea acroptilonica

gall wasp

Knapweed, Russian (Rhaponticum repens; = Acroptilon repens)

Bangasternus fausti

seedhead weevil

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

Bangasternus orientalis

seedhead weevil

Starthistle, yellow (Centaurea solstitialis)

Botanophila seneciella

seedhead fly

Ragwort, tansy (Senecio jacobaea; = Jacobaea vulgaris)

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

Chaetorellia acrolophi

seedhead fly

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

Chaetorellia australis

seedhead fly

Starthistle, yellow (Centaurea solstitialis)

Cheilosia grossa (formerly C. corydon)

stem fly

Thistle, slenderflower (Carduus tenuiflorus); thistle, Italian (C. pycnocephalus)

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)

Cystiphora schmidti

stem/leaf gall midge

Skeletonweed, rush (Chondrilla juncea)

Diorhabda carinulata C (formerly D. elongata)

leaf beetle

Saltcedar (Tamarix ramosissima)

Euhrychiopsis lecontei E

stem weevil

Watermilfoil, Eurasian (Myriophyllum spicatum)

Eustenopus villosus

seedhead 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/root weevil

Thistle, Canada (Cirsium arvense)

Hyles euphorbiae

defoliating moth

Spurge, leafy (Euphorbia 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

seedhead weevil

Starthistle, yellow (Centaurea solstitialis)

Larinus minutus

seedhead weevil

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, meadow (C. x moncktonii; = C. jacea x nigra; = C. debeauxii; = C. pratensis); knapweed, diffuse (C. diffusa)

Larinus obtusus

seedhead weevil

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, meadow (C. x moncktonii; = C. jacea x nigra; = C. debeauxii; = C. pratensis)

Leucoptera spartifoliella

twig mining moth

Broom, Scotch (Cytisus scoparius)

Longitarsus jacobaeae

root/defoliating flea beetle

Ragwort, tansy (Senecio jacobaea; = Jacobaea vulgaris)

Mecinus janthiniformis (formerly M. janthinus)

stem-boring weevil (Dalmatian toadflax)

Toadflax, Dalmatian (Linaria dalmatica)

Mecinus janthinus

stem-boring weevil (yellow toadflax)

Toadflax, yellow (Linaria vulgaris)

Metzneria paucipunctella

seedhead moth

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

Microlarinus lareynii

seed weevil

Puncturevine (Tribulus terrestris)

Microlarinus lypriformis

stem weevil

Puncturevine (Tribulus terrestris)

Nanophyes marmoratus

flower bud weevil

Loosestrife, purple (Lythrum salicaria)

Oberea erythrocephala

stem-boring beetle

Spurge, leafy (Euphorbia esula)

Phrydiuchus tau

crown/root weevil

Sage, Mediterranean (Salvia aethiopis)

Pterolonche inspersa

root-boring moth

Knapweed, diffuse (Centaurea diffusa)

Puccinia chondrillina

rust fungus

Skeletonweed, rush (Chondrilla juncea)

Puccinia jaceae var. solstitialis

rust fungus

Starthistle, yellow (Centaurea solstitialis)

Rhinocyllus conicus A

seedhead 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 antirrhini (formerly Gymnetron antirrhini)

seedhead weevil

Toadflax, yellow (Linaria vulgaris)

Sphenoptera jugoslavica

root-boring/gall beetle

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

Subanguina picridis

stem/leaf gall nematode

Knapweed, Russian (Rhaponticum repens; = Acroptilon repens)

Terellia virens

seedhead 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)

Tyria jacobaeae B

defoliating moth

Ragwort, tansy (Senecio jacobaea; = Jacobaea vulgaris)

Tyta luctuosa

defoliating moth

Bindweed, field (Convolvulus arvensis)

Urophora affinis

seedhead gall fly

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

Urophora cardui

stem gall fly

Thistle, Canada (Cirsium arvense)

Urophora quadrifasciata

seedhead gall fly

Knapweed, spotted (Centaurea stoebe; = C. stoebe ssp. micranthos); knapweed, meadow (C. x moncktonii; = C. jacea x nigra; = C. debeauxii; = C. pratensis); knapweed, diffuse (C. diffusa)

Urophora sirunaseva

seedhead gall fly

Starthistle, yellow (Centaurea solstitialis)

Urophora stylata A

seedhead 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 Diorhabda carinulata (formerly D. elongata) interstate shipment permits have been suspended.

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 and weevil releases often augment inadequate native populations. It is currently only available commercially.