Resistance to Sphaerotheca macularis (powdery mildew) was assessed on clones of four strawberry plants grown under polyethylene tunnels where epidemic conditions can be readily induced by withholding irrigation. The results showed a high correlation with field assessments. There was no correlation between the resistance scores from young seedlings grown in the glasshouse and the same plants scored, when mature, in the field. Resistance to Phytophthora cactorum (crown rot) was assessed after inoculating petiole bases of detached leaves with a mycelial disc. After five days in moist conditions the spread of the fungal-induced necrosis was used as a measure of resistance. Conditions for screening seemed best from February to April in the young leaves of plants which had been kept under fluorescent lights. A high level of resistance was found in certain clones of Fragaria vesca and in their hexaploid and decaploid derivatives. Screening was also achieved by planting four-week-old seedlings adjacent to agar discs in which P. cactorum was growing. Susceptible genotypes died within 14 days.