TABLE 1.
Summary of North American biocontrol agents discussed.
| Bioherbicide agent | Target weed | Specificity of control agent | Intended system | Product formulation | Stage of development | Initial scientific report |
|---|---|---|---|---|---|---|
| Fungal agents | ||||||
| Colletotrichum gloeosporioides f.sp. aeschynomene | Northern jointvetch (Aeschynomene virginica) | Also affects Sesbania exaltata Boyette et al. (2011) | Field crops: Rice, soybean | Aqueous spore suspensions Sandrin et al. (2003) | Registered with EPA in 1982, no longer available | Daniel et al. (1973) |
| Colletotrichum gloeosporioides f.sp. malvae | Round leaf mallow (Malva pusilla) | Lethal effect limited to Malvaceae family Mortensen (1988) | Field crops: Wheat, rye, flax, lentil, barley, canola, sunflower, soybean, oats, mustard, sugar beet and buckwheat | Aqueous spore suspension Mortensen (1988) | Registered with PMRA from 1992 to 1994 (marketed by Philom Bios Inc.) | Mortensen (1988) |
| Colletotrichum orbiculare | Spiny cocklebur (Xanthium spinosum) | Known pathogen of the Cucurbitaceae Harata and Kubo (2014) | Pasture and field crops | Aqueous spore suspension Auld et al. (1988) | Research phase | Auld et al. (1988) |
| Colletotrichum truncatum | Hemp sesbania (Sesbania exaltata) | Pathogenicity reported as limited to Leguminosae Boyette (1991) Minor pathogenicity on Matricaria perforata Hynes et al. (2010) | Field crops | Aqueous spore suspension Boyette et al. (2007) | Research phase | Boyette (1991) |
| Phoma chenopodicola | Lamb’s quarters (Chenopodium album), Creeping thistle (Cirsium arvense), Green foxtail (Setaria viridis), Annual mercury (Mercurialis annua) | Not tested on other species | Field crops such as sugar beet and corn | Active ingredient isolated from live culture of P. chenopodicola using organic solvents [MeOH-H2O (1:3) solution] Cimmino et al. (2013) | Research phase | Cimmino et al. (2013) |
| Phoma herbarum | Dandelion (Taraxacum officinale) | Reported as a potential control agent for Trianthema portulacastrum Ray and Vijayachandran (2013) | Turf | Suspension of mycelia in potato dextrose broth Neumann and Boland (1999) | Research phase | Neumann Brebaum (1998); Neumann and Boland (1999) |
| Phoma macrostoma | Dicot plants | Affects most monocots but not dicots Bailey et al. (2011) | Turf | Granules composed of mycelial fragments and flour (final iteration of inoculum formula) Bailey et al. (2011) | 94-44B strain registered with EPA and PMRA in 2011 | Graupner et al. (2003); Bailey et al. (2011) |
| Sclerotinia minor | Dandelion (Taraxacum officinale), White clover (Trifolium repens), and Broadleaf plantain (Plantago minor) | Wide host range, predominantly dicot species Melzer et al. (1997) | Turf | Barley grits containing actively growing mycelia Abu-Dieyeh and Watson (2006) | Registered with PMRA as Sarritor in 2010, no longer available | Riddle et al. (1991) |
| Chondrostereum purpureum strain HQ1 | Re-growth of deciduous trees and shrubs | Wide host range Setliff (2002) | Forestry | Paste containing mycelia PMRA (2002) | Registered as Mycotech Paste with PMRA in 2002, and with EPA in 2005 | Setliff (2002) |
| Chondrostereum purpureum strain PFC 2139 | Re-growth of deciduous trees and shrubs | Wide host range Setliff (2002) | Forestry | Paste containing mycelia EPA (2004) | Registered as Chontrol Paste with EPA in 2004, and with PMRA in 2007, commercially available in both regions | Setliff (2002) |
| Puccinia thlaspeos | Dyer’s woad (Isatis tinctoria) | Isatis tinctoria only EPA (2002) | Ecological management | Spray containing leaf fragments of infected Isatis tinctoria | Registered as Woad Warrior with EPA in 2002, no longer commercially available | Lovic et al. (1988) |
| Alternaria destruens | Dodder species (Cuscata spp.) | Observed to affect several unspecified crop species EPA (2005) | Alfalfa, cranberries, carrots, peppers, tomatoes, eggplant, blueberries, and woody ornamentals | Wettable power and granules containing spores | Registered as Smolder G and Smolder WP with EPA in 2005, no longer commercially available | Simmons (1998) |
| Phytophthora palmivora | Strangler vine (Morrenia odorata) | Weak pathogen of some crop species Ridings et al. (1973) | Citrus orchards | Aqueous spore suspension | Registered as DeVine with EPA in 1981, re-registered in 2006. No longer commercially available | Burnett et al. (1973) |
| Bacterial agents | ||||||
| Pseudomonas fluorescens strain D7 | Downy brome (Bromus tectorum) | Effect is limited to Bromus tectorum Kennedy et al. (2001) | Field crops | Cell-free filtrate prepared from nutrient broth culture Gealy et al. (1996) | Research phase | Kennedy et al. (1991) |
| Pseudomonas fluorescens strain BRG100 | Green foxtail (Setaria viridis) | Not identified | Not specified | Granules prepared from live culture in nutrient broth, oat flour, maltose and molasses Caldwell et al. (2012) | Research phase | Quail et al. (2002) |
| Pseudomonas fluorescens strain WH6 | Inhibits most of the species tested | Non-specific | Not specified | Cell-free filtrate Banowetz et al. (2008) | Research phase | Banowetz et al. (2008) |
| Viral agents | ||||||
| Tobacco Mild Green Mosaic Tobamovirus | Tropical soda apple (Solanum viarum) | Also affects Capsicum spp. and Nicotiana spp. Font et al. (2009); EPA (2015) | Pastures | Extract from virus-infected tobacco leaf in sodium phosphate buffer used in experimental phase | Registered with EPA in 2015 | Ferrell et al. (2008) |
| Araujia Mosaic Virus | Moth plant (Araujia hortorum) | Also affects Morrenia odorata, Oxypetalum caeruleum and Gomphocarpus spp. | Ecosystem management | Virus-infected leaves of Morrenia odorata in sodium phosphate buffer | Research discontinued because of pathogenicity on Gomphocarpus fruticosus Elliott et al. (2009) | Elliott et al. (2009) |
| Unspecified virus resembling Tobacco Rattle Virus | Impatiens glandulifera | Also affects species within Chenopodium and Nicotiana Kollmann et al. (2007) | Ecosystem management | Virus-infected leaves of Impatiens glandulifera in phosphor extraction buffer | Research phase | Kollmann et al. (2007) |
| \'Obuda Pepper Virus | Solanum nigrum | Wide host range Tobias et al. (1982) | Ecosystem management | Mechanical inoculation | Research phase | Kazinczi et al. (2006) |
| Pepino Mosaic Virus | Solanum nigrum | Wide host range including Amaranthaceae, Chenopodiacee, Compositae, Convolvulaceae, Malvaceae, Plantaginaceae and Solanaceae Papayiannis et al. (2012) | Ecosystem management | Mechanical inoculation | Research phase | Kazinczi et al. (2006) |