Hi all: Since it was mentioned soft skin insects might not be hurt by Jim
Fischer I decided to look around. It is said here: "It has been reported to
infect approximately 200 species of insects and other arthropods."
Wonder what these 200 species of insects are? Think I will look around!
By the way, below...mosquitoes.....are they hard shell? And we are talking
spiracles again for effective treatment???? Wow......
Regards,
Dee A. Lusby
_http://www.entomology.wisc.edu/mbcn/kyf607.html_
(http://www.entomology.wisc.edu/mbcn/kyf607.html)
Metarhizium anisopliae, formerly known as Entomophthora anisopliae, is a
widely distributed soil-inhabiting fungus. The first use of M. anisopliae as a
microbial agent against insects was in 1879, when Elie Metchnikoff used it in
experimental tests to control the wheat grain beetle, Anisoplia austriaca. It
was later used to control the sugar beet curculio, Cleonus punctiventris. A
member of the Hyphomycetes class of fungi, M. anisopliae is categorized as a
green muscardine fungus due to the green color of the sporulating colonies.
It has been reported to infect approximately 200 species of insects and other
arthropods. Although M. anisopliae is not infectious or toxic to mammals,
inhalation of spores could cause allergic reactions in sensitive individuals.
M. anisopliae generally enters insects through spiracles and pores in the
sense organs. Once inside the insect, the fungus produces a lateral extension
of hyphae, which eventually proliferate and consume the internal contents of
the insect. Hyphal growth continues until the insect is filled with mycelia.
When the internal contents have been consumed, the fungus breaks through the
cuticle and sporulates, which makes the insect appear "fuzzy." M. anisopliae
can release spores (conidia) under low humidity conditions (<50%). In
addition, M. anisopliae can obtain nutrition from the lipids on the cuticle. The
fungus can also produce secondary metabolites, such as destruxin, which have
insecticidal properties on moth and fly larvae.
Some insects have developed physiological mechanisms to reduce infection by
fungi such as M. anisopliae. For example, the desert locust produces
antifungal toxins, which can inhibit the germination of spores. In addition, insects
can escape infection by molting rapidly or developing a new integument before
the fungus can penetrate the cuticle.
The successful mass culture of M. anisopliae and development of methods of
mass-producing infective spores has led to the commercial development of this
fungus as a microbial insecticide. M. anisopliae is grown on a large scale in
semi-solid fermentation-- similar to that used in the production of
_Bacillus thuringiensis_ (http://www.entomology.wisc.edu/mbcn/fea207.html) --and the
spores can then be formulated as a dust. The fungal spores can also be grown
on sterilized rice in plastic bags for small-scale production. M. anisopliae
is sensitive to temperature extremes; spore viability decreases as storage
temperatures increase and virulence decreases at low temperatures.
Bioblast is a commercially available formulation of M. anisopliae that is
used to control termites such as Reticulitermes sp. The fungus is applied into
wood known to contain active termite galleries. Termites in these galleries
are exposed to direct contact with the fungus. In addition to direct contact
with the fungus, infection of other termites in the colony occurs when
grooming individuals exposed to the fungus spread the pathogen to healthy,
non-infected individuals in the population. Laboratory studies have shown that death
occurs within 4 to 10 days, depending on temperature.
No other products containing M. anisopliae are currently registered, but the
fungus has controlled many other insect pests in experimental trials,
including Japanese beetle, black vine weevil, and mosquitoes. Sprayable
formulations have been used to control meadow spittlebug on sugar cane and coffee
leafminer and the froghopper, Tomaspis saccharina, in Trinidad and Grenada. M.
anisopliae is highly pathogenic to many species of ticks, and is being
considered as a microbial control agent for the management of ticks and Lyme disease.
However, this fungus may also infect and kill beneficial organisms. In
laboratory assays, the thrips predator _Orius insidiosis_
(http://www.entomology.wisc.edu/mbcn/kyf101.html) showed a high rate of susceptibility to M.
anisopliae.
- Raymond A. Cloyd, University of Illinois
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