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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #236041
Title: Best linear unbiased prediction of host range of the facultative parasite Colletotrichum gloeosporioides f. sp. salsolae, a potential biological control agent of Russian thistle

Author
item Berner, Dana
item Bruckart, William
item Cavin, Craig
item Thomas, Jami
item Carter, Melissa
item Luster, Douglas - Doug

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2009
Publication Date: 8/22/2009
Citation: Berner, D.K., Bruckart, W.L., Cavin, C.A., Michael, J.L., Carter, M.L., Luster, D.G. 2009. Best linear unbiased prediction of host range of the facultative parasite Colletotrichum gloeosporioides f. sp. salsolae, a potential biological control agent of Russian thistle. Biological Control. 158-168.

Interpretive Summary: Tumbleweed or Russian thistle is an introduced invasive weed in N. America. It is widely distributed in the U.S. and is a target of biological control efforts. The parasitic fungus Colletotrichum gloeosporioides f. sp. salsolae is a potential biological control agent of tumbleweed. Host range tests were conducted in quarantine to determine whether the fungus is safe to release in N. America. To arrive at anticipated disease reactions of each species as a whole, disease reaction and DNA data sequences were analyzed with mixed model equations to produce Best Linear Unbiased Predictors (BLUPs) for each species. These results showed that: the fungus was highly specific to only a few species; species in the tumbleweed genus Salsola were most susceptible to the fungus and significantly more susceptible than any other species; six species in closely related genera were significantly less susceptible than tumbleweed; mixed model equations can be used to effectively to predict disease reaction for this fungus.

Technical Abstract: Tumbleweed or Russian thistle (Salsola tragus L.) is an introduced invasive weed in N. America. It is widely distributed in the U.S. and is a target of biological control efforts. The facultative parasitic fungus Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. f. sp. salsolae is a potential biological control agent of tumbleweed. Host range tests were conducted in quarantine to determine whether the fungus is safe to release in N. America. To arrive at anticipated disease reactions of each species as a whole, disease reaction data were combined with a relationship matrix derived from DNA sequences and analyzed with mixed model equations to produce Best Linear Unbiased Predictors (BLUPs) for each species. These results showed that: the fungus was highly specific to only a few species; species in the genus Salsola were most susceptible to the fungus and significantly more susceptible than any other species; six species in the closely related genera Bassia, Salicornia, and Sarcocornia were also susceptible but had significantly lower BLUPs (were significantly less susceptible) than S. tragus; the disease ratings for these species, based on a 0-4 scale, were not nearly as severe as for S. tragus; a 0-9 rating scale would have more clearly shown differences in disease severity; mixed model equations can be used equally effectively to predict disease reaction for a facultative parasitic fungus as well as an obligate parasitic fungus.