| Host plant | Bio agent | Agent type |
Bachelor's button - Centaurea cyanus
| Chaetorellia australis | seed head fly |
| | Urophora quadrifasciata | seed head gall fly |
| Black knapweed - Centaurea nigra | Urophora quadrifasciata
| seed head gall fly |
| Brown knapweed - Centaurea jacea | Urophora quadrifasciata | seed head gall fly |
| Bull thistle - Cirsium vulgare | Cheilosia corydon | crown / root fly |
| | Rhinocyllus conicus | seed head weevil |
| | Urophora stylata | seed head gall fly |
| Canada thistle - Cirsium arvense | Altica carduorum | root / defoliating flea beetle |
| | Ceutorhynchus litura | crown / root weevil |
| | Rhinocyllus conicus | seed head weevil |
| | Urophora cardui | stem gall fly |
| Dalmatian toadflax - Linaria dalmatica | Calophasia lunula | defoliating moth |
| | Gymnetron antirrhini | seed head weevil |
| | Gymnetron linariae | root-galling weevil |
| | Mecinus janthinus | stem boring weevil |
| Diffuse knapweed - Centaurea diffusa | Agapeta zoegana | root boring moth |
| | Bangasternus fausti | seed head weevil |
| | Chaetorellia acrolophi | seed head fly |
| | Cyphocleonus achates | root weevil |
| | Larinus minutus | seed head weevil |
| | Metzneria paucipunctella | seed head moth |
| | Pterolonche inspersa | root boring moth |
| | Sphenoptera jugoslavica | root boring beetle |
| | Terellia virens | seed head fly |
| | Urophora affinis | seed head gall fly |
| | Urophora quadrifasciata | seed head gall fly |
| Field bindweed - Convolvulus arvensis | Aceria malherbae | eriophyid mite |
| | Tyta luctuosa | defoliating moth |
| French broom - Genista monspessulana | Bruchidius villosus | seed beetle |
| Gorse - Ulex europaeus | Exapion ulicis | seed weevil |
| | Tetranychus lintearius | spider mite |
| Italian thistle - Carduus pycnocephalus | Cheilosia corydon | crown / root fly |
| | Rhinocyllus conicus | seed head weevil |
| | Trichosirocalus horridus | crown/root weevil |
Leafy spurge - Euphorbia esula
| Aphthona abdominalis | root / defoliating flea beetle |
| | Aphthona cyparissiae | root / defoliating flea beetle |
| | Aphthona czwalinae | root / defoliating flea beetle |
| | Aphthona flava | root / defoliating flea beetle |
| | Aphthona lacertosa | root / defoliating flea beetle |
| | Aphthona nigriscutis | root / defoliating flea beetle |
| | Chamaesphecia crassicornis | root boring moth |
| | Hyles euphorbiae | defoliating moth |
| | Oberea erythrocephala | root / stem boring beetle |
| | Spurgia esula | shoot tip gall midge |
Meadow knapweed - Centaurea jacea x nigra
| Larinus minutus | seed head weevil |
| | Larinus obtusus | seed head weevil |
| | Metzneria paucipunctella | seed head moth |
| | Urophora quadrifasciata | seed head gall fly |
| Mediterranean sage - Salvia aethiopis | Phrydiuchus tau | root / crown weevil |
| | Phrydiuchus spilmani | root / crown weevil |
| Milk thistle - Silybum marianum | Rhinocyllus conicus | seed head weevil |
Musk thistle - Carduus nutans
| Cheilosia corydon | crown / root fly |
| | Rhinocyllus conicus | seed head weevil |
| | Trichosirocalus horridus | crown/root weevil |
| | Urophora solstitialis | seed head gall fly |
| Plumeless thistle - Carduus acanthoides | Rhinocyllus conicus | seed head weevil |
| Puncturevine - Tribulus terrestris | Microlarinus lareynii | seed weevil |
| | Microlarinus lypriformis | stem boring weevil |
Purple loosestrife- Lythrum salicaria
| Galerucella calmariensis | defoliating beetle |
| | Galerucella pusilla | defoliating beetle |
| | Hylobius transversovittatus | root weevil |
| | Nanophyes marmoratus | seed head weevil |
| Rush skeletonweed - Chondrilla juncea | Bradyrrhoa gilveolella | root boring moth |
| | Cystiphora schmidti | stem / leaf gall midge |
| | Eriophyes chondrillae | bud gall mite |
| | Puccinia chondrillina | leaf rust fungus |
Russian knapweed - Acroptilon repens
| Subanguina picridis | leaf stem gall nematode |
Russian thistle - Salsola kali
| Coleophora klimeschiella | leaf mining moth |
| | Coleophora parthenica | stem boring moth |
| St. Johnswort - Hypericum perforatum | Agrilus hyperici | root / stem boring beetle |
| | Aplocera plagiata | defoliating moth |
| | Chrysolina hyperici | defoliating beetle |
| | Chrysolina quadrigemina | defoliating beetle |
| | Zeuxidiplosis giardi | leaf gall midge |
| Saltcedar - Tamarix ramosissima | Diorhabda elongata | defoliating beetle |
| | Aceria genistae | eriophyid gall mite |
| Scotch broom - Cytisus scoparius | Bruchidius villosus | seed beetle |
| | Exapion fuscirostre | seed weevil |
| | Leucoptera spartifoliella | twig mining moth |
Scotch thistle - Onopordum acanthium
| Rhinocyllus conicus | seed head weevil |
| | Trichosirocalus horridus | crown/root weevil |
| Slender-flowered thistle - Carduus tenuiflorus | Cheilosia corydon | crown / root fly |
| | Rhinocyllus conicus | seed head weevil |
| | Trichosirocalus horridus | crown/root weevil |
| Spotted knapweed - Centaurea stoebe (C. maculosa) | Agapeta zoegana | root boring moth |
| | Bangasternus fausti | seed head weevil |
| | Chaetorellia acrolophi | seed head fly |
| | Cyphocleonus achates | root weevil |
| | Larinus minutus | seed head weevil |
| | Larinus obtusus | seed head weevil |
| | Metzneria paucipunctella | seed head moth |
| | Pelochrista medullana | root boring moth |
| | Pterolonche inspersa | root boring moth |
| | Sphenoptera jugoslavica | root boring beetle |
| | Terellia virens | seed head fly |
| | Urophora affinis | seed head gall fly |
| | Urophora quadrifasciata | seed head gall fly |
| Squarrose knapweed - Centaurea virgata | Urophora affinis | seed head gall fly |
| | Urophora quadrifasciata | seed head gall fly |
| Tansy ragwort -Senecio jacobaea | Botanophila seneciella | seed head fly |
| | Longitarsus jacobaeae | root / defoliating flea beetle |
| | Tyria jacobaeae | defoliating moth |
| Yellow starthistle - Centaurea solstitialis | Bangasternus orientalis | seed head weevil |
| | Chaetorellia australis | seed head fly |
| | Eustenopus villosus | seed head weevil |
| | Larinus curtus | seed head weevil |
| | Urophora quadrifasciata | seed head gall fly |
| | Urophora sirunaseva | seed head fly |
| Yellow toadflax - Linaria vulgaris | Calophasia lunula | defoliating moth |
| | Gymnetron antirrhini | seed head weevil |
