This chapter examines whether Cladosporium
tenuissimum Cooke, a destructive
hyperparasite of rust spores, can be
exploited as a BCA of rust fungi. It reports on
tests carried out to evaluate C. tenuissimum
effectiveness against rusts in the genera
Melampsora, Cronartium, Peridermium,
Uromyces and Puccinia, focusing on its
modes of action, the fine-level analysis of
the fungal host\u2013hyperparasite interface, the
antifungal compounds it produces, and its
ability to reduce disease, both in vitro and in
planta. Since effective biological control is
impossible without due consideration of the
ecology of the BCA, as well as of the other
partners involved, and an examination of
their spatial relationships and interaction
with the environment, attention is also paid
to the biological nature of the fungus,
in particular to those characteristics that
enable it to survive in natural habitats and
retain activity under varying environmental
conditions
