Best linear unbiased prediction of host-range of the facultative parasite Colletotrichum gloeosporioides f. sp. salsolae, a potential biological control agent of Russian thistle

• Published in: Biological control Vol. 51; no. 1; pp. 158 - 168
• Main Authors: Berner, D.K., Bruckart, W.L., Cavin, C.A., Michael, J.L., Carter, M.L., Luster, D.G.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.10.2009
• Subjects: adverse effects; Aizoaceae; Amaranthaceae; Animal model; Anthracnose; Apiaceae; Asteraceae; biological control; biological control agents; BLUP; Brassicaceae; broadleaf weeds; Cactaceae; Campanulaceae; Chenopodiaceae; Classical biological control; Colletotrichum gloeosporioides; Colletotrichum gloeosporioides f. sp. salsolae; Cucurbitaceae; Cupressaceae; data analysis; Deuteromycotina; Disease prediction; disease severity; equations; Fabaceae; GDATA; Glomerella cingulata; Henderson’s mixed model equations; host plants; host range; host specificity; Host-range testing; internal transcribed spacers; invasive species; Invasive weeds; Malvaceae; molecular sequence data; nontarget organisms; noxious weeds; Nyctaginaceae; Phytolaccaceae; plant pathogenic fungi; Plant pathogens; Poaceae; Polygonaceae; PROC MIXED; Quartet puzzling; Reduced animal model; Relationship matrix; Salsola; Salsola tragus; SAS; Solanaceae; statistical analysis; Tragus; weed control; Animal model; Salsola tragus; Reduced animal model; Henderson’s mixed model equations; SAS; PROC MIXED; Invasive weeds; Anthracnose; Chenopodiaceae; Classical biological control; Colletotrichum gloeosporioides f. sp. salsolae; Quartet puzzling; GDATA; BLUP; Deuteromycotina; Host-range testing; Relationship matrix; Plant pathogens; Disease prediction
• ISSN: 1049-9644; 1090-2112
• DOI: 10.1016/j.biocontrol.2009.06.003

Russian thistle or tumbleweed ( Salsola tragus L.) is an introduced invasive weed in N. America. It is widely distributed in the US and is a target of biological control efforts. The fungus Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. f. sp . salsolae (CGS) is a facultative parasite under evaluation for classical biological control of this weed. Host-range tests were conducted with CGS in quarantine to determine whether the fungus is safe to release in N. America. Ninetytwo accessions were analyzed from 19 families: Aizoaceae, Alliaceae, Amaranthaceae, Apiaceae, Asteraceae, Brassicaceae, Cactaceae, Campanulaceae, Chenopodiaceae, Cucurbitaceae, Cupressaceae, Fabaceae, Malvaceae, Nyctaginaceae, Phytolaccaceae, Poaceae, Polygonaceae, Sarcobataceae, and Solanaceae and 10 tribes within the Chenopodiaceae: Atripliceae, Beteae, Camphorosmeae, Chenopodieae, Corispermeae, Halopepideae, Polycnemeae, Salicornieae, Salsoleae, and Suaedeae. These included 62 genera and 120 species. To facilitate interpretation of results, disease reaction data were combined with a relationship matrix derived from internal transcribed spacer DNA sequences and analyzed with mixed model equations to produce Best Linear Unbiased Predictors (BLUPs) for each species. Twenty-nine species (30 accessions) from seven closely-related Chenopodiaceae tribes had significant levels of disease severity as indicated by BLUPs, compared to six species determined to be susceptible with least squares means estimates. The 29 susceptible species were: 1 from Atripliceae, 4 from Camphorosmeae, 1 from Halopepideae, 2 from Polycnemeae, 6 from Salicornieae, 8 from Salsolae, and 7 from Suaedeae. Most species in the genus Salsola, which are all introduced and weedy, were very susceptible and damaged by CGS. Statistical comparisons and contrasts of BLUPs indicated that these Salsola species were significantly more susceptible than non-target species, including 15 species from relatives in the closely-related genera Bassia (= Kochia), Nitrophila, Salicornia, Sarcocornia, and Suaeda. Of the 29 susceptible species, 10 native or commercially important species in N. America were identified as needing additional tests to determine the extent of any damage caused by infection.