  The contribution of Delta(1232) to the piN -> pipiN reaction is examined by
making use of the chiral reduction formula developed by Yamagishi and Zahed.
The influence of the pi-Delta-Delta and rho-N-Delta interactions on this
reaction, which has not been regarded as important so far, is considered for
all channels with the initial pi^{+ -}p states. The total cross sections are
calculated to tree level for the energy up to T_{pi}=400 MeV. Although the
pi-Delta-Delta and rho-N-Delta interactions give a small effect on the pi^{+}p
-> pi^{+}pi^{+}n, pi^{-}p -> pi^{+}pi^{-}n and pi^{-}p -> pi^{0}pi^{0}p
channels, the pi^{+ -}p -> pi^{+ -}pi^{0}p channels are found to be sensitive
to these interactions.
