(Wize) A.H.S.Br. & G.Sm. (1957)
Isaria fumosorosea Wize (1904) Spicaria fumosorosea (Wize) Vassiljevsky (1929)
Paecilomyces fumosoroseus is the widely-known name of an entomopathogenic fungus, whose currently accepted name is Isaria fumosorosea.  It shows promise as a biological pesticide with an extensive host range.
When a conidium or blastospore of Paecilomyces fumosoroseus lands on a suitable host, it produces enzymes to penetrate the insect's cuticle. 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 or the anal opening. The mycelia spread in the hemolymph and tissues, eventually emerging from the insect and producing conidia. Mortality of the insect has been ascribed to the drainage of its nutrients, the destruction of its tissues and the release of toxins.
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
Paecilomyces fumosoroseus has been used to control insect pests of plants grown for the production of cut flowers, ornamentals growing in greenhouses and nurseries, vegetable and cole crops, cotton, maize, rice and plantation crops.
A comparison made between several entomopathogenic hyphomycetes showed that Paecilomyces fumosoroseus provided more effective control of the cabbage-heart caterpillar, Crocidolomia binotalis, than did either Beauveria bassiana or Metarhizium anisopliae.
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. No commercial formulation of Paecilomyces fumosoroseus is currently available in the USA but a commercial product is being marketed in Europe under the trade name "PreFeRal".
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, bumblebees or a wide range of non-target arthropods.
- Brown AHS, Smith G. (1957). "The genus Paecilomyces Bainier and its perfect stage Byssochlamys Westling". Transactions of the British Mycological Society 40 (1): 17–89. doi:10.1016/s0007-1536(57)80066-7.
- "Paecilomyces fumosoroseus (Wize) A.H.S. Br. & G. Sm. 1957". MycoBank. International Mycological Association. Retrieved 2011-11-24.
- Environmental Protection Agency
- Dr Rajan Laboratories
- European Commission: Review report for the active substance Paecilomyces fumosoroseus
- Vega, Fernando E., Bioactive Agents Research Unit
- Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) as a potential mycoparasite on Sphaerotheca fuliginea (Ascomycotina: Erysiphales)
- Efficacy of Entomopathogenic Fungi, Paecilomyces fumosoroseus, Beauvena bassiana and Metarhizium anisopliae var. majus Against Crocidolomia binotalis (Lepidoptera; Pyralidae)
- PreFeRal product information
- Nengel, S. Preferal WG : Acute oral and contact toxicity to the honey bee, Apis mellifera L., in the laboratory. Biobest N.V.