''Isaria fumosorosea'' is an entomopathogenic fungus, formerly known as '' Paecilomyces fumosoroseus''. It shows promise as a biological pesticide with an extensive host range.Dr Rajan Laboratories
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Life cycle

When a

conidium A conidium ( ; : conidia), sometimes termed an asexual chlamydospore or chlamydoconidium (: chlamydoconidia), is an Asexual reproduction, asexual, non-motility, motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word f ...

or blastospore of ''Isaria fumosorosea'' lands on a suitable host, it produces enzymes to penetrate the insect's

cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...

. A germ tube then grows into the haemocoel and the fungus proliferates inside the insect’s body. The fungus can also enter through the spiracles, the

mouth A mouth also referred to as the oral is the body orifice through which many animals ingest food and animal communication#Auditory, vocalize. The body cavity immediately behind the mouth opening, known as the oral cavity (or in Latin), is also t ...

or the anal opening. The

mycelia Mycelium (: mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Its normal form is that of branched, slender, entangled, anastomosing, hyaline threads. Fungal colonies composed of mycelium are fo ...

spread in the

haemolymph Hemolymph, or haemolymph, is a fluid, similar to the blood in invertebrates, that circulates in the inside of the arthropod's body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph ce ...

and tissues, eventually emerging from the insect and producing

conidia A conidium ( ; : conidia), sometimes termed an asexual chlamydospore or chlamydoconidium (: chlamydoconidia), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also ...

. Mortality of the insect has been ascribed to the drainage of its nutrients, the destruction of its tissues and the release of toxins.

Host range

This fungus has a wide host range that includes insects in over twenty five different families and many species of mite. Agricultural pest insects which are susceptible to infection include the diamondback moth (''Plutella xyllostella''), the Russian wheat aphid (''Diuraphis noxia'') and the silverleaf whitefly (''Bemisia argentifolii''). Among mites, susceptible species include the spotted spider mite (''Tetranychus urticae''), the European red mite (''Panonychus ulmi''), the brown mite ('' Byrobia rubrioculus'') and the apple rust mite ('' Aculus schlectendali'').

Use in biological control

''Isaria fumosorosea'' has been used to control insect pests of plants grown for the production of

cut flowers Cut flowers are flowers and flower buds (often with some Plant stem, stem and leaf) that have been cut from the plant bearing it. It is removed from the plant for decorative use. Cut greens are leaves with or without stems added to the cut flow ...

, ornamentals growing in greenhouses and nurseries, vegetable and cole crops, cotton, maize, rice and plantation crops. It has also been found to reduce the development and spread of powdery mildew, '' Sphaerotheca fuliginea'', on cucumbers. A comparison made between several entomopathogenic hyphomycetes showed that ''Isaria fumosorosea'' (as ''Paecilomyces fumosoroseus'') provided more effective control of the cabbage-heart caterpillar, '' Crocidolomia binotalis'', than did either '' Beauveria bassiana'' or ''

Metarhizium anisopliae ''Metarhizium anisopliae'' is a fungus, the type species in the ''Metarhizium'' genus. It grows naturally in soils throughout the world and causes disease in various insects by acting as a parasitoid. Ilya Ilyich Mechnikov, Ilya I. Mechnikov nam ...

''. Research at the USDA-ARS Bioactive Agents Research Unit in Peoria showed that blastospores start germinating at a faster rate on the cuticle of silverleaf whiteflies than do conidia. This suggests that the use of blastospores rather than conidia for the development of formulations would be advantageous. The fungus neither grows nor develops at temperatures above 32 °C and is not thought to be pathogenic to humans. It has not been found to be toxic to rats in laboratory experiments and is not considered to be harmful to birds, honey bees,Nengel, S. ''Preferal WG : Acute oral and contact toxicity to the honey bee, Apis mellifera L., in the laboratory.'' Biobest N.V. bumblebees or a wide range of non-target arthropods.

References

External links

Light-regulated asexual reproduction in Paecilomyces fumosoroseus

Germination of conidia and blastospores of Paecilomyces fumosoroseus on the cuticle of the silverleaf whitefly, Bemisia argentifolii
{{Taxonbar, from=Q10614986 Clavicipitaceae Biological pest control Insect diseases Fungi described in 1904 Biopesticides Parasitic fungi Fungus species