Resource Database

Resource Number: 14500

Title: Field Guide for the Biological Control of Weeds in Eastern North America

Publisher: USDA Forest Service - Forest Health Assessment and Applied Sciences Team

Resource Type: Field guide

Description:

This guide focuses on the most problematic weeds in eastern North America for which there are at least some biocontrol agents established and/or available. Multiple photos and descriptions of each weed included in this guide emphasize key identification traits and plant ecology.

Last Updated: February 27, 2026

Contributors:

Domain(s)/Area(S):

• Natural Resources
  • Biological Control
  • Weeds

Locations:

Subject
Hungarian clearwing moth  (Chamaesphecia hungarica)
tropical soda apple  (Solanum viarum)
alligatorweed  (Alternanthera philoxeroides)
alligatorweed flea beetle  (Agasicles hygrophila)
alligatorweed thrips  (Amynothrips andersoni)
melaleuca  (Melaleuca quinquenervia)
melaleuca leaf weevil  (Oxyops vitiosa)
giant salvinia  (Salvinia molesta)
salvinia weevil  (Cyrtobagous salviniae)
Canada thistle stem-gall fly  (Urophora cardui)
Canada thistle  (Cirsium arvense)
tree-of-heaven  (Ailanthus altissima)
musk thistle, nodding thistle  (Carduus nutans)
spotted knapweed  (Centaurea stoebe ssp. micranthos)
air-potato  (Dioscorea bulbifera)
hydrilla  (Hydrilla verticillata)
old world climbing fern  (Lygodium microphyllum)
purple loosestrife  (Lythrum salicaria)
Eurasian watermilfoil  (Myriophyllum spicatum)
water lettuce  (Pistia stratiotes)
mile-a-minute vine, Asiatic tearthumb  (Persicaria perfoliata)
multiflora rose  (Rosa multiflora)
cypress spurge  (Euphorbia cyparissias)
black dot spurge flea beetle  (Aphthona nigriscutis)
copper leafy spurge flea beetle  (Aphthona flava)
brown-legged spurge flea beetle  (Aphthona lacertosa)
leafy spurge gall midge  (Spurgia esulae)
knapweed gall fly  (Urophora affinis)
knapweed seed head fly  (Urophora quadrifasciata)
knapweed seedhead moth  (Metzneria paucipunctella)
sulfur knapweed moth  (Agapeta zoegana)
knapweed root weevil  (Cyphocleonus achates)
lesser knapweed flower weevil  (Larinus minutus)
knapweed peacock fly  (Chaetorellia acrolophi)
green knapweed clearwing fly  (Terellia virens)
bull thistle  (Cirsium vulgare)
bull thistle gall fly  (Urophora stylata)
musk thistle head weevil  (Rhinocyllus conicus)
puccinia rust  (Puccinia carduorum)
black dog-strangling vine, black swallowwort  (Vincetoxicum nigrum)
spiny plumeless thistle, plumeless thistle  (Carduus acanthoides)
thistle crown weevil  (Trichosirocalus horridus)
nodding thistle gall fly  (Urophora solstitialis)
spurge hawkmoth  (Hyles euphorbiae)
minute spurge flea beetle  (Aphthona abdominalis)
brown dot leafy spurge flea beetle  (Aphthona cyparissiae)
black leafy spurge flea beetle  (Aphthona czwalinai)
Australian pyralid moth  (Austromusotima camptozonale)
yellow toadflax  (Linaria vulgaris)
milfoil moth  (Acentria ephemerella)
milfoil weevil  (Euhrychiopsis lecontei)
waterlettuce weevil  (Neohydronomus affinis)
waterlettuce moth  (Spodoptera pectinicornis)
black-margined loosestrife beetle  (Galerucella calmariensis)
purple loosestrife root mining weevil  (Hylobius transversovittatus)
flower feeding weevil  (Nanophyes marmoratus)
Rose rosette virus (RRV)  (Emaravirus RRD)
rose bud and flower mite  (Phyllocoptes fructiphilus)
clearwing moth  (Chamaesphecia crassicornis)
dog-strangling vine, European swallowwort, pale swallow-wort  (Vincetoxicum rossicum)
water fern  (Salvinia minima)
waterhyacinth mite  (Orthogalumna terebrantis)
pickerelweed borer  (Bellura densa)
tortoise beetle  (Gratiana boliviana)
Hydrilla tuber weevil  (Bagous affinis)
Hydrilla stem weevil  (Bagous hydrillae)
meadow knapweed  (Centaurea x moncktonii)
bronze knapweed root borer  (Sphenoptera jugoslavica)
brown-winged root moth  (Pelochrista medullana)
brown-winged knapweed moth  (Pterolonche inspersa)
blunt knapweed flower weevil  (Larinus obtusus)
poison hemlock  (Conium maculatum)
defoliating hemlock moth  (Agonopterix alstroemeriana)
squarrose knapweed  (Centaurea virgata)
broad-nosed knapweed seed head weevil  (Bangasternus fausti)
golden loosestrife beetle  (Galerucella pusilla)
common St. Johnswort  (Hypericum perforatum)
St. John's wort beetle  (Agrilus hyperici)
St. Johnswort Inchworm  (Aplocera plagiata)
lesser St. John's wort beetle  (Chrysolina hyperici)
greater St. John's wort beetle  (Chrysolina quadrigemina)
St. Johnswort midge  (Zeuxidiplosis giardi)
ragwort flea beetle  (Longitarsus jacobaeae)
ragwort seed fly  (Botanophila seneciella)
slenderflower thistle  (Carduus tenuiflorus)
Scotch thistle  (Onopordum acanthium)
musk thistle leaf beetle  (Psylliodes chalcomera)
root-boring moth  (Eteobalea intermediella)
stem-boring weevil  (Mecinus janthinus)
clearwing moth  (Chamaesphecia tenthrediniformis)
toadflax flower-eating beetle  (Brachypterolus pulicarius)
Toadflax Brocade  (Calophasia lunula)
Italian plumeless thistle  (Carduus pycnocephalus)
blessed milkthistle, milk thistle  (Silybum marianum)
diffuse knapweed  (Centaurea diffusa)
stem-mining fly  (Pegomya euphorbiae)
toadflax  (Linaria)
cinnabar moth  (Tyria jacobaeae)
brown knapweed  (Centaurea jacea)
black knapweed  (Centaurea nigra)
alpine knapweed, Tyrol knapweed  (Centaurea nigrescens)
Dalmatian toadflax  (Linaria dalmatica)
leafy spurge gall midge  (Spurgia capitigena)
knapweeds  (Centaurea)
marsh thistle  (Cirsium palustre)
toadflax root-galling weevil  (Rhinusa linariae)
toadflax seed weevil  (Rhinusa antirrhini)
weevil  (Rhinusa neta)
thistle tortoise beetle  (Cassida rubiginosa)
melaleuca psyllid  (Boreioglycaspsis melaleucae)
Canada thistle rust mite  (Aceria anthocoptes)
Japanese knotweed  (Reynoutria japonica)
squarrose knapweed  (Centaurea virgata ssp. squarrosa)
giant knotweed  (Reynoutria sachalinensis)
spotted knapweed  (Centaurea stoebe)
Tobacco Mild Green Mosaic Virus (TMGMV)  (Tobamovirus TMGMV)
scentless chamomile  (Tripleurospermum inodorum)
mile-a-minute weevil  (Rhinoncomimus latipes)
biological control (general)
clearwing moth  (Chamaesphecia empiformis)
flea beetle  (Altica carduorum)
Bohemian knotweed, Hybrid Japanese knotweed  (Reynoutria x bohemica)
Tortricid moth  (Lobesia euphorbiana)
Canada thistle stem mining weevil  (Hadroplontus litura)
weed management (general)
red-tailed thistle fly  (Terellia ruficauda)
tansy ragwort  (Jacobaea vulgaris)
leafy spurge  (Euphorbia virgata)
Meadow Knapweed  (Centaurea thuillieri)
St Johnswort aphid  (Aphis chloris)
clearwing moth  (Chamaesphecia spp.)
syrphid fly  (Cheilosia grossa)
Black-headed Conch  (Cochylis atricapitana)
thistle leaf beetle  (Lema cyanella)
stem-boring weevil  (Mecinus janthiniformis)
stem-mining fly  (Pegomya curticornis)
scentless chamomile gall midge  (Rhopalomyia tripleurospermi)
weevil  (Microplontus edentulus)
Drab Looper  (Minoa murinata)
Pear-shaped Weevils  (Omphalapion hookerorum)
Eriophyid mite  (Floracarus perrepae)
air potato leaf beetle  (Lilioceris cheni)
plant hopper  (Megamelus scutellaris)
lygodium defoliator moth  (Neomusotima conspurcatalis)
Brazilian peppertree  (Schinus terebinthifolia)
leaf-feeding moth  (Hypena opulenta)
shoot-galling weevil  (Rhinusa pilosa)
knotweed species (nonnative)  (Reynoutria spp.)
Brazilian peppertree seed chalcid  (Megastigmus transvaalensis)
leafy spurge stem borer  (Oberea erythrocephala)
verticillium wilt  (Verticillium nonalfalfae)
Japanese knotweed psyllid  (Aphalara itadori)
(Eteobalea spp.)
alligatorweed stemborer  (Macrorrhinia endonephele)
Australian hydrilla leaf mining fly  (Hydrellia balciunasi)
Asian hydrilla leaf mining fly  (Hydrellia pakistanae)
midge  (Cricotopus lebetis)
hydrilla leafcutter moth  (Parapoynx diminutalis)
melaleuca gall midge  (Lophodiplosis indentata)
melaleuca gall midge  (Lophodiplosis trifida)
Fergusonina gall flies  (Fergusonina turneri)
Fergusobia nematode  (Fergusobia quinquenerviae)
chevroned waterhyacinth weevil  (Neochetina bruchi)
mottled waterhyacinth weevil  (Neochetina eichhorniae)
waterhyacinth pathogen  (Cercospora piaropi)
Urophora jaceana  (Urophora jaceana)
Dalmatian toadflax seed-galling weevil  (Rhinusa dieckmanni)
large thistle weevil  (Cleonis pigra)
(Chamaesphecia astatiformis)
(Eteobalea serratella)
ragwort flea beetle - Italian biotype  (Longitarsus jacobaeae Italian biotype)
ragwort flea beetle - Swiss biotype  (Longitarsus jacobaeae Swiss biotype)
Canada thistle bud weevil  (Larinus carlinae)
gall midge  (Spurgia euphorbiae)
Meadow knapweed complex  (Centaurea jacea complex)
Black-headed Conch  (Cochylichroa atricapitana)
(Lobesiodes euphorbiana)
knotweed psyllid - Hokkaido line  (Aphalara itadori Hokkaido line)
knotweed psyllid - Kyushu line  (Aphalara itadori Kyushu line)
knotweed psyllid - Murakami line  (Aphalara itadori Murakami line)