Improved procedures for the in vivo and in vitro production of conidial inoculum of Venturia species of pome fruit

Summary Full descriptions are provided of a set of improved in vivo and in vitro procedures to allow the efficient production and long-term storage of conidial inoculum of Venturia species pathogenic on pome fruit. Uniform stands of seedlings inoculated and incubated under standard conditions are used to produce conidial inoculum in vivo, while production in vitro involves establishing a culture on the surface of sterile muslin saturated with 10% malt extract. Conidia retain viability following storage for at least 2 years at -20°C. These materials and methods are now used routinely for several types of investigation; they are described together in one publication for the first time and have been shown to provide some advantages over previously reported procedures.