[Edited_by_A._Ciancio,_C.N.R.,_Bari,_Italy_and_K.(Bookos.org)

264
L.P.S. VAN DER GEEST
The presence of rhizoids is an important property of the fungus for a successful
transmission of the disease to a new host: the dead host (mummy) remains fixed to
the plant surface and does not fall on the soil. In this way, chances for a successful
transmission are increased.
The formation of resting spores is an interesting phenomenon. Sometimes,
resting spores are present in large numbers. It is assumed that they may assist the
fungus to overcome poor favorable conditions, such as extreme periods of drought.
However, we still know very little about the role of resting spores and the conditions
under which they germinate are poorly understood. The fungus may also survive
unfavorable conditions in other manners. Klingen, Wærsted, and Westrum (2008)
showed that Neozygites floridana may survive cold winter periods in the form of
hyphal bodies inside hibernating females of T.urticae.
Most entomophthoralean fungi are difficult to culture in artificial culture media.
For mass production, it is often necessary to use live host. Species that can be
cultured in artificial media have usually a broad host spectrum. On the other hand,
species with a restricted host range can hardly be grown outside their host, although
some progress have been made with very complex culture media. Entomophthorales
observed in mites are given in Table 2.
Table 2. Entomophthoralean fungi infecting mites and their hosts.
Fungus species Mite species Mite family References
Not identified
Entomophthoralean
species
Arctoseius sp.
Macrocheles
peregrinus
Pergamasus
crassipes
Tetranychus
desertorum
Arctoseiinae
Macrochelidae
Parasitidae
Tetranychidae
Bałazy and Wiśniewski
(1989)
Milner (1985)
Milner (1985)
Walter (1999)
Resting spores of
Entomophtoralean
species
Agistemus
Asca sp.
Amblyseius
igarassuensis
Stigmaeidae
Ascidae
Phytoseiidae
Van der Geest, De Moraes,
Navia, and Tanzini (2002)
Basidiobolus sp. Tetranychus urticae Tetranychidae See: Chandler et al. (2000)
Conidiobolus sp. Bryobia sp. Tetranychidae Bałazy, Mietkiewski,
Tkaczuk, Wegensteiner,
and Wrzosek (2008)
Conidiobolus
brefeldionis
Tyrophagus
perniciosus
Acaridae See: Chandler et al. (2000)
Conidiobolus
chapowski
Pergamasus Parasitidae See: Chandler et al. (2000)