4.1.3. Hyperparasites of tropical tar spot fungi
Tropical tar spot fungi (Sordariomycetes: Phyllachorales), along with
Erysiphaceae and Meliolales, are among the most frequently
hyperparasitized fungal lineages (Cannon, 1991; Hawksworth, 1981).
Parbery (1978) listed some common hyperparasitic fungi of Phyllachora and Linochora species, namely Phaeodothis winteri (Dothideomycetes: Pleosporales), as well as
species of Cercospora, Mycosphaerella (Dothideomycetes:
Mycosphaerellales), Seimatosporium (Sordariomycetes:
Amphisphaeriales), and other dematiaceous fungi. Other potential
hyperparasites of Phyllachorales are cited by Baker and Dale (1951),
Sivanesan and Kranz (1975), and Sutton (1980). Caution is warranted when
interpreting fungal associates of tar spot fungi. The
anamorph–teleomorph connections in Phyllachorales are not well
understood; asexual states may be misinterpreted as hyperparasites, and
vice versa (M. Mardones, personal communication). Moreover, it may be
difficult to determine whether an associated fungus is a hyperparasite
of the tar spot fungus or simply uses the cavities or the lesions as
entrance for direct plant parasitism (Hawksworth, 1981).
Hyperparasitic fungi of Phyllachorales use different strategies to
infect their hosts. Some hyperparasites grow through the perithecial
ostiole of the tar spot fungus to expose their conidiophores, whereas
others form a narrow layer of conidiogenous cells closely adjacent to
the inner perithecial layer of the phyllachoralean fungus and remain
almost invisible on the leaf surface (M. Mardones, personal
communication). The coelomycete Diplodia sp. (Dothideomycetes:
Botryosphaeriales), for example, forms its pycnidia inside the ascomata
of Phyllachora sacchari (Rao, 1967). Hyperparasitized
colonies of Phyllachora can be recognized by their dull surface
and the necrotized host tissue around them (Gams et al., 2004).