Bulletin of Insectology (2010) 63, 71-78

Eric W. Riddick and Ted E. Cottrell (2010)
Is the prevalence and intensity of the ectoparasitic fungus Hesperomyces virescens related to the abundance of entomophagous coccinellids?
Bulletin of Insectology 63 (1), 71-78
Abstract: Hesperomyces virescens Thaxter is an obligate ectoparasitic fungus that parasitizes coccinellids in several countries. It transmits horizontally between coccinellid adults via social contact. The relative abundance of coccinellids in an agroecosystem may affect the transmission dynamics of H. virescens. We predicted that the prevalence and intensity of H. virescens would be greatest on the more abundant coccinellid species. We collected lady beetles from plant foliage in a 480 ha agroecosystem in Byron, Georgia, USA, from April through October 2007. The prevalence and intensity of the parasite was greatest on Harmonia axyridis (Pallas), which was the most abundant coccinellid collected in early spring and summer. There was a positive relationship between parasite infection of the exotic H. axyridis and the native Olla v-nigrum Mulsant; parasite infection increased as relative abundance of both species increased. The parasite was seldom on one of its original hosts, Hippodamia convergens Guérin-Méneville, and never on the exotic Coccinella septempunctata L. even though the latter species was the second most abundant coccinellid in the agroecosystem. Lack of infection of an abundant coccinellid such as C. septempunctata could result from low encounter rates and not just low susceptibility to infection. H. virescens transmission may vary depending on frequency of contact between infected and uninfected coccinellids in shared habitats.
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Database assignments for author(s): Eric W. Riddick, Ted E. Cottrell

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
Coccinella septempunctata (predator)			U.S.A. (SE)
Harmonia axyridis (predator)			U.S.A. (SE)
Hippodamia convergens (predator)			U.S.A. (SE)
Olla v-nigrum (predator)			U.S.A. (SE)
Hesperomyces virescens (entomopathogen)			U.S.A. (SE)