Paecilomyces

Definition

A genus of filamentous fungi (Ascomycota: Eurotiales: Aspergillaceae) encompassing species that are entomopathogenic, nematophagous, or phytopathogenic. In arthropod biology, several species—notably P. lilacinus and P. fumosoroseus—are deployed as biological control agents against insect and mite pests, infecting hosts through cuticular penetration and producing asexual conidia on distinctive divergent phialides. The genus also includes opportunistic pathogens of insects in natural and agricultural ecosystems, and some species are used in commercial mycoinsecticide formulations.

Etymology

Example

Paecilomyces lilacinus is applied as a soil drench to suppress root-feeding nematodes and has shown efficacy against thrips and whitefly nymphs in greenhouse crops, while P. fumosoroseus (now often classified in Isaria) was developed commercially for control of diamondback moth and other lepidopteran pests.

Related Terms

• entomopathogenic fungi
• Biological control
• mycoinsecticide
• Beauveria
• Metarhizium
• Isaria
• phialide
• conidium
• nematophagous

Usage Notes

Taxonomic revision has reclassified several former Paecilomyces species (e.g., P. fumosoroseus to Isaria, P. tenuipes to Ophiocordyceps), so older literature may use outdated combinations. In biocontrol literature, 'Paecilomyces' often specifically denotes P. lilacinus for nematode suppression. The genus is morphologically distinguished from Penicillium by its long, divergent phialides with pointed tips rather than flask-shaped phialides.