These data indicate that exogenously apply of BRs can act efficiently in plants as plant- resistance enhancers and immuno-modulators when applied at the appropriate concentration and stage of plant develop- ment. Since BRs confer their various ability on shifting a complex sequence of biochemical processes and the production of various chemical defence compound in plants, they are considered as promising phytohormone
from a practical point of view. Based on the employ- ment of very small amounts, they friendly exhibit their effects on environment in general. In this regard, the
protective effect of BRs against some phytopathogens
has helped to open up new approaches for plant dis-
eases management in agriculture.