  By pursuing the goal to find new variables in the COROT field-of-view we
characterised a sample of stars located in the lower part of the instability
strip. Our sample is composed of stars belonging to the disk population in the
solar neighbourhood. We found that 23% of the stars display multiperiodic light
variability up to few mmag of amplitude. uvbyBeta photometry fixed most of the
variables in the middle of the instability strip and high-resolution
spectroscopy established that they have vsin i>100 km/s. The comparison with
delta Sct stars in the whole Galaxy shows slightly different features, i.e.,
most delta Sct stars have a 0.05-mag redder (b-y)_0 index and lower vsin i
values. Additional investigation in the open cluster NGC 6633 confirms the same
incidence of variability, i.e., around 20%. The wide variety of pulsational
behaviours of delta Sct stars (including unusual objects such as a variable
beyond the blue edge or a rapidly rotating high-amplitude pulsator) makes them
very powerful asteroseismic tools to be used by COROT. Being quite common among
bright stars, delta Sct stars are suitable targets for optical observations
from space.
