| Abutilon hirtum (Indian mallow) | Seeds available on the internet for conservation and restoration purposes. | Yes | Yes | |
| Abutilon indicum (country mallow) | | Yes | Yes | |
| Acacia angustissima (prairie acacia) | Seeds available to be shipped locally and internationally. | Yes | Yes | |
| Acacia longifolia (golden wattle) | Seeds for sale over the internet. | Yes | Yes | |
| Achillea millefolium (yarrow) | Seeds available locally and internationally for forage use, ornamental use. | Yes | Yes | Rumball, 2005 |
| Aegilops cylindrica | | Yes | Yes | |
| Ageratum houstonianum (blue billygoat weed) | | Yes | Yes | |
| Agrostis capillaris (common bent) | | Yes | | |
| Alopecurus myosuroides (black-grass) | Contamination of grass seeds. No introduction information | | Yes | Mackay, 1964 |
| Alternaria japonica (pod spot of radish) | infected seed | Yes | Yes | Neergaard, 1945; Petrie, 1978; Tahvonen, 1979; Tohyama & Tsuda, 1990; Tohyama & Tsuda, 1995 |
| Alternaria triticina (leaf blight of wheat) | | Yes | | Logrieco et al., 1990 |
| Amaranthus dubius (leafy amaranth) | | Yes | Yes | |
| Ambrosia artemisiifolia (common ragweed) | | Yes | Yes | |
| Ambrosia trifida (giant ragweed) | | Yes | Yes | |
| Anethum graveolens (dill) | | Yes | Yes | Jana & Shekhawat, 2010 |
| Antigonon leptopus (coral vine) | Seeds sold online | Yes | Yes | Burke & DiTommaso, 2011 |
| Aronia x prunifolia | | Yes | Yes | |
| Artemisia biennis (biennial wormwood) | In flaxseed or grain | Yes | | Jehlík, 1984; Suominen, 1979 |
| Arthraxon hispidus (small carpetgrass) | | Yes | Yes | |
| Avena barbata (slender oat) | Is a common contaminant in seed mixtures | Yes | | |
| Axonopus fissifolius | | Yes | Yes | |
| Brachypodium sylvaticum (slender false brome) | Not documented but possible | Yes | Yes | |
| Brassica nigra (black mustard) | deliberate | Yes | | |
| Bromus hordeaceus (soft brome) | Common forage grass contaminate | Yes | Yes | Smith, 1968 |
| Bromus secalinus (rye brome) | Principally spread as a contaminant of cereal seed | Yes | | Hubbard, 1954 |
| Buddleja asiatica (dog tail) | Especially since the species is an ornamental and a medicinal plant | Yes | Yes | Plants for a Future, 2013 |
| Bunias orientalis (Turkish warty-cabbage) | | Yes | | Jehlik & Slavik, 1968 |
| Cenchrus biflorus (Indian sandbur) | | Yes | Yes | |
| Centaurea macrocephala | | Yes | | |
| Centratherum punctatum (lark daisy) | Seeds sold online (http://davesgarden.com) | Yes | Yes | |
| Chromolaena odorata (Siam weed) | As a seed contaminant | Yes | Yes | Chevalier, 1949 |
| Ciborinia allii (neck rot of onion) | | Yes | Yes | Lacy & Lorbeer, 1995 |
| Cirsium mexicanum (Mexican thistle) | Contaminant in crop seeds | Yes | Yes | Holm et al., 1997 |
| Clavibacter michiganensis subsp. sepedonicus (Potato ring rot) | | Yes | Yes | Boer et al., 2005; Boer SHde, 1987 |
| Claviceps africana (ergot) | presumed means of reaching Americas | Yes | | Bandyopadhyay et al., 1998; Pazoutová & Frederickson, 2005 |
| Claviceps fusiformis (pearl millet ergot) | | Yes | Yes | Pathak et al., 1984 |
| Claviceps sorghi (sorghum ergot) | | Yes | Yes | Bandyopadhyay et al., 1996 |
| Coconut cadang-cadang viroid (cadang cadang disease) | Unrestricted movement of coconut germplasm from affected areas in the Philippines. | Yes | Yes | |
| Cosmos caudatus (wild cosmos) | popular garden plant | Yes | Yes | |
| Cowpea aphid-borne mosaic virus | CABMV is seedborne in cowpea seeds | Yes | Yes | |
| Crassostrea virginica (eastern oyster) | | Yes | Yes | |
| Cylindropuntia fulgida (jumping cholla) | Seeds of C. fulgida are easily found in online-shops to be shipped all over the world | Yes | | |
| Cylindropuntia rosea (hudson pear) | Seeds of C. fulgida are easily found in online-shops to be shipped all over the world | Yes | | |
| Cynodon nlemfuensis (African Bermuda-grass) | Seeds are widely commercialized | Yes | Yes | Cook et al., 2005 |
| Dactylis glomerata (cocksfoot) | | Yes | Yes | |
| Daucus carota (carrot) | Wild carrot occurs as seed or grain contaminant | Yes | Yes | |
| Desmodium incanum (creeping beggerweed) | Forage of hydro-mulch seeds sold for planting could contain this species either as the main forage o | Yes | Yes | |
| Didymella fabae (leaf and pod spot) | Infected seed | Yes | Yes | Hewett, 1966; Kaiser, 1997 |
| Digitaria insularis (sourgrass) | | Yes | | |
| Elephantopus mollis (elephant's foot) | Assumed | Yes | Yes | |
| Eragrostis lehmanniana (Lehmann lovegrass) | Used as a forage grass | Yes | Yes | Uchytil, 1992 |
| Erigeron karvinskianus (Karwinsky’s fleabane) | Widely available on the Internet and in many dedicated shops and nurseries (F Barthelat, pers. obs) | Yes | Yes | |
| Erodium botrys (long-beaked stork's bill) | In grass or other seed | Yes | Yes | |
| Erodium cicutarium (common storksbill) | | Yes | Yes | |
| Glechoma hederacea (ground ivy) | | Yes | Yes | |
| Globodera pallida (white potato cyst nematode) | Netherlands to Canada | Yes | Yes | Franco et al., 1998 |
| Globodera rostochiensis (yellow potato cyst nematode) | Netherlands to South America | Yes | | DAO et al., 1971 |
| Glyceria declinata (small sweet grass) | | Yes | Yes | |
| Glyceria maxima (reed sweet-grass) | Seed sold in Victoria in the 1940s | Yes | Yes | Gippsland and Northern Co-operative CoLtd, 1940 |
| Gypsophila paniculata (baby’s breath) | | Yes | Yes | Darwent, 1975 |
| Harpophora maydis (late wilt of maize) | on imported seed | Yes | | Pécsi & Németh, 1998 |
| Hedychium coccineum (scarlet ginger lily) | | Yes | Yes | Branney, 2005; Dave's Garden, 2014 |
| Hedychium coronarium (white butterfly ginger lily) | | Yes | | |
| Hedychium flavescens (wild ginger) | | Yes | | |
| Hedychium gardnerianum (kahili ginger) | | Yes | | |
| Heracleum mantegazzianum (giant hogweed) | | Yes | Yes | Tiley et al., 1996 |
| Holcus lanatus (common velvet grass) | Has been found to make up as much as 10% of the seed base in forage seed mixtures sold in Britain | Yes | Yes | |
| Hymenula cerealis (Cephalosporium stripe) | The potential for seed transmission exists, but data are not available to document its significance. | Yes | Yes | Murray, 2006 |
| Hyoscyamus niger (black henbane) | a potential source of invasion, as seed is available online | Yes | Yes | |
| Jasminum fluminense (Brazilian jasmine) | Plants and seeds are sold online | Yes | Yes | |
| Juncus ensifolius (swordleaf rush) | Seed sold for native plant restoration | Yes | | NZPCN (New Zealand Plant Conservation Network), 2015 |
| Leptochloa fusca (sprangletop) | | Yes | Yes | |
| Leucanthemum vulgare (oxeye daisy) | | Yes | Yes | |
| Limnocharis flava (yellow bur-head) | | | Yes | |
| Linaria vulgaris (common toadflax) | As contaminant in crop seed | Yes | Yes | |
| Lolium perenne (perennial ryegrass) | Commonly sown species | Yes | Yes | |
| Lupinus polyphyllus (garden lupin) | Accidental | Yes | | |
| Melinis repens (natal redtop) | Seeds available online | Yes | | California Native Plant Link Exchange, 2012 |
| Microlaena stipoides (meadow rice grass, meadow ricegrass) | as pasture seed contaminant (?) | Yes | | |
| Mimosa diplotricha (giant sensitive plant) | | Yes | | Anon., 2001b; Parsons & Cuthbertson, 1992 |
| Moniliophthora roreri (frosty pod rot) | For cocoa production | Yes | | |
| Mononychellus tanajoa (cassava green mite) | Accidental introduction, common pathway | Yes | Yes | |
| Nandina domestica (Nandina) | Seeds available via internet | Yes | | |
| Orobanche cernua (nodding broomrape) | Potential introduction on contaminated crop seed | Yes | Yes | |
| Orobanche cumana (sunflower broomrape) | | Yes | Yes | |
| Orobanche ramosa (branched broomrape) | | Yes | Yes | |
| Oryza barthii | Potential | Yes | Yes | |
| Parentucellia viscosa (yellow glandweed) | Difficult to detect among grass seed | Yes | Yes | |
| Parthenium hysterophorus (parthenium weed) | | Yes | Yes | PAG, 2000 |
| Paspalum urvillei (Vasey grass) | | | Yes | B & T World Seeds, 2012 |
| Paspalum vaginatum (seashore paspalum) | | Yes | Yes | |
| Pennisetum polystachion (mission grass) | | Yes | | Westbrooks, 1989 |
| Pennisetum setaceum (fountain grass) | Listed by at least two online seed sellers and on E-Bay | Yes | | Hazzard's Greenhouse, 2012; World Seeds, 2012 |
| Phaius tankervilleae (nun’s-hood orchid) | Seeds are readily available from several outlets, inc. Amazon.com | Yes | Yes | |
| Phleum pratense (timothy grass) | | Yes | | |
| Phomopsis vexans (Phomopsis blight of eggplant) | infected seed | Yes | | Edgerton & Moreland, 1921; Porter, 1943; Vishunavat & Kumar, 1993 |
| Physalis peruviana (Cape gooseberry) | | Yes | Yes | |
| Plantago coronopus (Buck's-horn plantain) | | Yes | Yes | |
| Plectranthus scutellarioides (coleus) | | Yes | Yes | Missouri Botanical Garden, 2014b; Wagner et al., 1999 |
| Raoiella indica (red palm mite) | Coconut seed found to carry R. indica when transported between regions | Yes | Yes | |
| Rhamphicarpa fistulosa | Seeds of invader can stick to (much) larger crop seeds. In theory this could disperse seeds over lon | | Yes | |
| Rottboellia cochinchinensis (itch grass) | Contaminated rice seed source of introduction in Campeche, Mexico | Yes | Yes | Valverde et al., 1999; Valverde et al., 2001 |
| Sesamia cretica (greater sugarcane borer) | | Yes | Yes | |
| Setaria parviflora (knotroot foxtail) | Accidental | Yes | | Milovic et al., 2010; NOBANIS, 2013; Ryves et al., 1996; Seed Regulatory Testing Branch, 2011 |
| Setaria verticillata (bristly foxtail) | | Yes | Yes | |
| Sida acuta (sida) | | Yes | | Smith, 2002; Waterhouse & Norris, 1987 |
| Silene gallica (common catchfly) | Seed found in imported clover seed | Yes | Yes | |
| Silene latifolia subsp. alba (white campion) | Seed contaminant | Yes | Yes | Alberta Weed Monitoring Network, 2014 |
| Sisymbrium irio | | Yes | Yes | |
| Solanum capsicoides (cockroach berry) | Seeds sold online | Yes | Yes | |
| Solanum mammosum (nipplefruit nightshade) | Intentionally cultivated as an ornamental or curiosity plant worldwide | Yes | Yes | PBI Solanum Project, 2014 |
| Solidago nemoralis (grey goldenrod) | Hypothetical | Yes | Yes | |
| Sporobolus africanus (rat’s tail grass) | can occur as a seed contaminant | Yes | Yes | |
| Stachys arvensis (staggerweed) | Potential seed contaminant | Yes | Yes | USDA-ARS, 2014 |
| Stachytarpheta cayennensis (blue snakeweed) | | Yes | | |
| Sternochetus mangiferae (mango seed weevil) | | Yes | Yes | |
| Strawberry necrotic shock virus (Strawberry necrotic shock virus) | | Yes | Yes | |
| Tetragonia tetragonioides (New Zealand spinach) | Common garden plant worldwide, and long available in gardening catalogues | Yes | Yes | Grubben & Denton, 2004; Roskruge, 2011; Sturtevant, 1919 |
| Thekopsora areolata (cherry spruce rust) | With or without cones | Yes | | Richardson, 1990 |
| Tradescantia spathacea (boat lily) | | Yes | Yes | |
| Trichoconiella padwickii (stackburn disease) | | Yes | Yes | Agarwal et al., 2006; Lau & Sheridan, 1975 |
| Trifolium hybridum (alsike clover) | | Yes | Yes | Clark & Malte, 1913; Minnesota Wildflowers, 2015; Online Atlas of the British and Irish Flora, 2016; USDA-ARS, 2016 |
| Triphasia trifolia (limeberry) | Seeds sold online | Yes | Yes | |
| Urochloa distachya (signal grass) | Commerce of forage seeds | Yes | Yes | New Zealand Ministry for Primary Industries, 2015 |
| Urochloa platyphylla (broadleaf signalgrass) | Introduced as a contaminant in grass and crop-seeds | Yes | Yes | USDA-ARS, 2014 |
| Urocystis agropyri (flag smut of wheat) | wheat and grass seed | Yes | Yes | Asaad & Abang, 2009; Richardson, 1990 |
| Urtica dioica (stinging nettle) | occurs as a contaminant of grass seed lots | Yes | Yes | Gooch, 1963 |
| Verbena litoralis (blue vervain) | Possible formerly carried as a contaminant in seed samples | Yes | | |
| Verbena rigida (stiff verbena) | | | Yes | Royal Horticultural Society, 2015 |
| Wisteria sinensis (Chinese wisteria) | Web search results in numerous sites selling wisteria seeds | Yes | | |
| Xanthium spinosum (bathurst burr) | | Yes | Yes | PIER, 2013 |