Insect Control: Biological and Synthetic Agents - Index of

390 11: Entomopathogenic Fungi and their Role in Regulation of Insect Populations
(Jensen et al., 1998), and some groups, such as
the Glomales, may be placed elsewhere eventually
(e.g., Bruns et al., 1993). Basidiobolus ranarum
and other Basidiobolus species, traditionally considered
as Zygomycetes, have now been placed in
the Chytridiomycetes, despite being nonflagellate
(Nagahama et al., 1995).
Figure 2 Tick (Ixodes ricinus) killed by Metarhizium anisopliae.
(Photo courtesy of C. Nielsen.)
Within the true Zygomycota, the class Trichomycetes
contains species often associated with insects.
While Sweeney (1981) described the species Smittium
morbosum (Trichomycetes) as a pathogen of
mosquitoes, most associations of the Trichomycetes
are symbiotic or weakly parasitic rather than true
pathogens (Beard and Adler, 2002; Cafaro, 2002).
Some species of Mucor (Mucorales) are occasionally
associated with insect mortality.
The majority of entomopathogenic species within
Zygomycota are contained in one order, the Entomophthorales.
More than 200 entomopathogenic
Entomophthorales species have been recognized.
They commonly cause spectacular epizootics and
are characterized in all genera but one (Massospora),
by the production of forcibly discharged
primary conidia. Many species are capable of producing
various types of secondary conidia from the
primary conidia and, in some cases, infection is
obligatorily through a secondary conidium. Many
species are also capable of producing resting spores,
long-lived zygospores or azygospores. These fungi
are generally obligate pathogens in nature, and
many species are presently difficult or impossible
to culture on artificial media.
Until around the 1960s, most entomopathogenic
Entomophthorales were contained within a
single genus, Entomophthora, but several years of
taxonomic revision have placed the species into
several genera. The main genera containing
entomopathogenic species are Conidiobolus, Entomophaga,
Entomophthora, Erynia, Furia, Massospora,
Neozygites, Pandora, Strongwellsea, and
Zoophthora.
Figure 3 Adult cabbage fly (Delia radicum) killed by Beauveria bassiana. This fungus produces clusters of white conidia. (Photo
courtesy of J. Eilenberg.)