Hirsutella is a genus of asexually reproducing fungi in the Ophiocordycipitaceae family, which contain about 65 species (Hodge 1998). It is a moniliaceous, entomopathogenic fungal pathogen, which produces an insecticidal protein named hirsutellin. Hirsutellin has been described to be toxic against a wide rage of small insects including larvae, aphids, mites and nematodes.

Hirsutella was originally described by French mycologist Narcisse Théophile Patouillard in 1892, creating interest in the use of these fungi as biological controls of insect pests. The teleomorphs of Hirsutella species belong to the genera Ophiocordyceps and Torrubiella. Hirsutella is a Hyphomycetes, a form-class of Fungi, part of what has often been referred to as Fungi imperfecti, Deuteromycota, or anamorphic fungi. Hyphomycetes lack closed fruiting bodies, and are often referred to as molds. They have unusual phialides that taper into a long narrow neck, and produce usually only 1–3 conidia in a dense terminal sphere of slime.

Most Important Hursutella Species

The genus Hursutella contain approximately 30 species. By no means all of these species are viable bio-control agents. The most important bio-control agents are Hirsutella verticillioides, Hirsutella thompsonii, Hirsutella citriformis and Hirsutella rhossiliensis. Rhossiliensis being very effective against nematodes. If you are up on your Spanish you might be interested in the report FAO Hirsutella put together jointly between the Instituto de Investigaciones and the Centro de Investigaciones Agropecuarias (CIAP), Universidad Central de Las Villas, Cuba.

Hirsutellia Mode of Action

Hirsutellia controls the growth of certain harmful bacteria and fungi, presumably by competing for nutrients, growth sites on plants, and by directly colonizing and attaching to fungal pathogens. A detailed description of the mode of action can be gleaned from the Journal of Invertebrate Pathology Entitled “The Mode of Action of Hirsutellin A on Eukaryotic Cells” In summary, Hirsutella has been found to be the first mycotoxin of a invertebrate mycopathogen determined to possess ribosomal inhibiting activity and appears to possess some specificity to invertebrate cells.

Research Related to Biocontrol Agent Hirsutellia

Toxicity of Hirsutella Against Mites– INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY

Toxicity of Hirsutella Against Mites- Departamento de Bioquímica y Biología Molecular I, Universidad Complutense

Hirsutellin A, a toxic protein produced in vitro by Hirsutella thompsonii– Station de Recherches de Pathologie Comparee INRACNRS, Saint-Christol-
Lez-Ales, France