Forty isolates of Botrytis cinerea were isolated from pepper (10 isolates).
strawberry (15 isolates), and grape (15 isolates) collected from different governorates
in Egypt. All tested isolates proved to be pathogenic to the hosts from which these
isolates were isolated. The current acquired fungicidal resistance level in the natural
population of Botrytis cinerea isolated from pepper, strawberry, and grape to the
fungicides Sumisclex and Tecto was estimated. Resistance factors to the tested
fungicides obviously differed from one isolate to the other. The fungus proved to be
unspecific to a certain host which means all fungus isolates belong to only one
population. The recalculated resistance factors ranged from 1.0 to 30.7 for Sumisclex
but do not change for Tecto. Fungal acquired resistance to Sumisclex was negatively
correlated with the catalase enzyme, while it was positively correlated with polyphenol
oxidase, peroxidase and catalase enzymes for Tecto. The content of flavonoids
(antioxidant substances) was higher in isolates resistant to Sumisclex than in sensitive
ones. No clear correlation was observed between the sterol content of resistant
isolates and the resistance to Sumisclex or Tecto.