Gibberella Saubinetii (Mont.) Sacc. on British Cereals: II. Physiological AKD Pathological Studies

Abstract

Summary G. Saubinetii (Mont.) Sacc., the conidial stage of which is known as Fusarium graminearum Schwabe, produces mature perithecia on natural and artificial substrata, given ample moisture and a uniform temperature of 21° to 22°C. British summer shade temperature does not suffice for this.The minimum temperature for the germination of conidia and ascospores is about 6°C. Between 5° and 10°C. both kinds of spores develop mycelia, and the fungus can infect cereal seedlings. The optimum temperature for vegetative growth of the fungus and the production of mature perithecia is about 24° C.; the maximum temperature for growth is about 37°C.In its vegetative and perithecial stages this fungus can withstand prolonged exposure to a temperature range of — 1° to — 20°C. and in its vegetative stage it persists through the winter in this country.Under storage conditions it retains its vitality for at least two years in its vegetative stage, and for at least one year (probably much longer) in its perithecial stage.Heating to 100°C. for five minutes under dry conditions kills G. Saubinetii on or in diseased grains, but this treatment of seed grain is not a practicable way of controlling the disease. G. Saubinetii causes “seedling blight” and “foot rot” of cereals, but is much less virulent than .F. culmorum and F. avenaceum in this respect. All three fungi attack the ears in a similar way, with similar virulence and with similar results. G. Saubinetii occurs throughout England and in Ireland, but full details of its frequency of occurrence in the British Isles have not yet been obtained.