Over the last few years, white mould disease was one of the most
important diseases causing severe losses on cucurbit plants in
many Egyptian governorates, particularly under commercial plastic
houses. Investigation was carried out to isolate and identify the
causative agent (s).Five fungal isolates were obtained from different
governorates and were pathogenic to Delta-star RZ hybrid of
cucumber. Moreover, the isolates obtained from the naturally infected
cucumber plants grown in Giza Governorate (Gizerat El-Dahab) were
the highly virulent. On the other hand, plants of eight cucumber
hybrids were evaluated for their susceptibility to infection by the
white mould disease. Results indicated that Delta-star RZ (hyb.) gave
the highest percentage of disease susceptibility, while Marmar hybrid
showed the less percentage. Data elucidated that the amounts of free,
total phenols and conjugated compounds were somewhat higher in the
non-infected healthy highly resistant hyb, Marmar than those observed
in the more susceptible hyb. Delta-star RZ particularly at 40 days after
infection. On the other hand, total free amino acids were increased in
response to infection with any highly virulent or low virulent isolate,
Delta-star RZ showed the highest figure particularly after 40 days than
the less susceptible hyb, Marmar.