Vertical Movement of the Spores of Metarhizium Anisopliae (Metsch.) Sorokin through Sand and Soil
File(s)
Date
1981-10Author
Reinke, Marjorie T.
Publisher
University of Wisconsin-Stevens Point, College of Natural Resources
Metadata
Show full item recordAbstract
The purpose of this research was to determine whether
spores of the green muscardine fungus, Metarhizium anisopliae
(Metsch.) Sorokin would migrate through sand and soil by the
action of water and a wetting agent under laboratory and
field conditions. M. anisopliae is an entomogenous pathogen
occurring naturally in soils and is widely used in
experimental microbial control attempts. Knowledge of the
migration of the spores of M. anisopliae could establish
the fungus as an effective agent in controlling hard-to-reach
soil inhabiting insect pests and encourage its use in
the field as a biological control agent.
Laboratory trials consisted of placing a spore suspension
of M. anisopliae on the surface of three types of
sterile soils, i.e. coarse sand, sand-loam mixture, and
soil of the Plainfield series which had been placed in
plexiglas columns. This topical application was followed
by 150 ml of sterile distilled water. Samples of the soils
were taken at 5cm intervals to a depth of 35cm. Spores
were found to have traveled to an average depth of 30cm in
the sand and Plainfield soil and 20cm in the sand-loam
mixture. Unsterile Plainfield soil was placed in a stainless
steel column and treated in the same manner as the
sterile soils. In this soil, the spores migrated to a
depth of 20cm.
The surface of eight one-quarter square meter field
plots were sprayed with a spore suspension of M. anisopliae.
.
At the end of two months, the fungus was found at a depth
of 18cm. M. anisopliae had migrated to a depth of 30cm after
four months. There was no evidence that M. anisopliae
occurred naturally in the soils of the test area.
A bioassay was devised to determine virulence of the
spores after traveling through the soils. The larvae of
the greater wax moth (Galleria mellonella) were inoculated
with spores of M. anisopliae which were obtained from the
cultures of the laboratory and field trials. All the larvae
died of green muscardine disease.
Based on an evaluation of past research and this investigation,
it is believed that M. anisopliae has a high potential
as a microbial control agent against soil-inhabiting
insects especially in conjunction with a pest management
system such as an integrated control program.