Host range, temperature response, survival, and overwintering of Alternaria cirsinoxia.

摘要: Abstract Alternaria cirsinoxia was evaluated for its host range, the influence of temperature on mycelial growth, and survival overwintering Canada thistle (Cirsium arvense) in Saskatchewan. With exception leafy spurge, range A. limited to species within Asteraceae. thistle, safflower, sunflower were most susceptible cirsinoxia, latter two being crop lesser importance Mycelium grew best at a constant 25°C cycles which alternated around mean 20–25°C. did not grow when exposed temperatures 0, 40, or 45°C 7 days. However, 0°C, mycelium survived able resume whereas 40 45°C, killed. In field, produced viable conidia senescent, basal leaves least 3–4 months after inoculation 1998 1999. Sporulation tended be higher than 1999, possibly favored by warmer, drier, sunnier conditions prevailing during July mid-September 1998. also overwintered infected 4°C, sampled from November until April field lowest probably due inoculum degradation as result surface flooding plots. Clusters chains chlamydospores abundant leaf stem debris plots inoculated 10 previously. subsequently sporulated this debris. Based these host-range tests, risks major nontarget Saskatchewan should minimal inundative application bioherbicide thistle. pathogen appears persist remain potentially infectious prolonged period time inoculation. Hence, longevity spread further minimize potential minor species.