Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2006
Publication Date: 6/1/2006
Citation: Bruckart, W.L., Cavin, C.A. 2006. Host range determination of collectotrichum gloeosporioides from russian thistle. Phytopathology. 96:S190
Technical Abstract: Salsola tragus (Russian thistle) is a major weed pest in the western United States. An isolate of Colletotrichum gloeosporioides (CG) from Hungary currently is a candidate for biological control of S. tragus. Risk assessment to determine potential non-target susceptibility involved inoculation of 64 species with 10^6 conidia from two-week-old CG cultures grown on V-8 Juice Agar at room temperature and lighting. Over half (36) of the test species were from the Chenopodiaceae, including seven cultivars of Beta vulgaris (Beet, Chard) and six cultivars of Spinaca oleracea (Spinach). Inoculated plants were incubated in a dark dew chamber at 25 C for 18 hr and then placed on a greenhouse bench (21 to 25 C, with natural light supplemented to give a 16 hr photoperiod) for observation of symptom development. Non-target infections (macroscopic symptoms) were noted on 14 non-target species in the Chenopodiaceae, including (genus, [number of symptomatic species]) Bassia (1) Chenopodium (6), Nitrophila (1), Salicornia (2), Salsola (3), Spinacia (6 cultivars) and Suaeda (1). All S. tragus were killed, and a native, rare plant (Suaeda taxifolia) was clearly infected. The other species had only minor symptoms.