Abstract
For sample collection of blighted potato leaflets to isolate Phytophthora infestans, a sample bag of folded newspaper having several pockets was evaluated. Several blighted leaflets were separately inserted in a bag and the sample bags were incubated at from -5 to 30°C. The leaflets were dehydrated gradually and prevented from rotting by bacteria. Sample lesions were inoculated onto potato tuber slices to assess fungus viability. The lower the temperature for sample storage, the longer the viable period of P. infestans in the lesion: more than 14 days at 3°C, 5-8 days at 20°C and 1-2 days at 30°C. As the fungus was viable long enough for sample collection by mail from any district of Japan, the newspaper bag technique was practically applied with success.
