Application of a simple freezing method for short-term storage of Phytophthora erythroseptica

The effect of different cold storage temperatures on the survival and in vi tro growth of isolates of Phytophthora erythroseptica Pethybr. and Phyropht hora infestans (Mont.) de Bary, originating from potato tubers, was assesse d. Agar plugs with growing mycelium were immersed in 10% glycerine and stor ed for 3 or 16 weeks as follows: (I) at -20 degreesC; (2) at -80 degreesC; or (3) for 1 h at -20 degreesC, then at -80 degreesC. Percent recovery of P . erythroseptica after 3 weeks of storage exceeded 90% and was significantl y higher (P = 0.05) than for isolates of P. infestans. After 4 months of st orage, recovery of P. erythroseptica was 100% for isolates stored at -80 de greesC and 0% for those at -20 degreesC. Storage of P. erythroseptica at -8 0 degreesC is a convenient method of maintaining isolates that are to be us ed in short-term studies.