title: Germination of Fusarium graminearum Ascospores and Wheat Infection are Affected by Dry Periods and by Temperature and Humidity During Dry Periods.
abstract: The effects of temperature and relative humidity (RH) on germination of Fusarium graminearum ascospores, and of dry periods (DP) of different lengths and of temperature and RH during DP on ascospore survival were studied both in vitro and in planta. Optimal temperatures for ascospore germination at 100% RH were 20 and 25°C; germination was ≤5% when ascospores were incubated at 20°C and RH ≤ 93.5%. Viable ascospores were found at all tested combinations of DP duration (0 to 48 h) × temperature (5 to 40°C) or RH (32.5 to 100% RH). Germination declined as DP duration and temperature increased. Germination was lower for ascospores kept at 65.5% RH during the DP than at 76.0, 32.5, or 93.5% RH. Equations were developed describing the relationships between ascospore germination, DP duration and temperature or RH during DP. Durum wheat spikes were inoculated with ascospores and kept dry for 0 to 48 h at approximately 15°C and 65% RH; plants were then kept in saturated atmosphere for 48 h to favor infection. Fungal biomass, measured as F. graminearum DNA by quantitative polymerase chain reaction, declined as DP increased to 24 and 48 h at 3 and 9 days postinfection but not in spikes at maturity.
authors.affiliation: First, second, and fourth authors: DI.PRO.VE.S. Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Piacenza, Italy; and second and third authors: CRA-GPG, Council for Agricultural Research and Economics, Genomics Research Centre, Fiorenzuola d'Arda (PC), Italy.
authors.forename: V
authors.initials: V
authors.lastname: Manstretta
authors.affiliation: First, second, and fourth authors: DI.PRO.VE.S. Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Piacenza, Italy; and second and third authors: CRA-GPG, Council for Agricultural Research and Economics, Genomics Research Centre, Fiorenzuola d'Arda (PC), Italy.
authors.forename: C
authors.initials: C
authors.lastname: Morcia
authors.affiliation: First, second, and fourth authors: DI.PRO.VE.S. Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Piacenza, Italy; and second and third authors: CRA-GPG, Council for Agricultural Research and Economics, Genomics Research Centre, Fiorenzuola d'Arda (PC), Italy.
authors.forename: V
authors.initials: V
authors.lastname: Terzi
authors.affiliation: First, second, and fourth authors: DI.PRO.VE.S. Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Piacenza, Italy; and second and third authors: CRA-GPG, Council for Agricultural Research and Economics, Genomics Research Centre, Fiorenzuola d'Arda (PC), Italy.
authors.forename: V
authors.initials: V
authors.lastname: Rossi
mesh_terms: D005670:Fusarium / Q000502:physiology*; D006813:Humidity; D010935:Plant Diseases / Q000382:microbiology*; D011891:Rain; D013172:Spores, Fungal / Q000502:physiology*; D013696:Temperature; D014908:Triticum / Q000382:microbiology*
keywords: Fusarium head blight; Gibberella zeae; modeling; spore survival