Seasonal patterns of persistence and infectivity of Metarhizium anisopliae var. acridum in grasshopper cadavers in the Sahel

S. P. Arthurs, M. B. Thomas, J. L. Lawton

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Field-based experiments were conducted to evaluate the fate and infectivity of the entomopathogenic fungus Metarhizium anisopliae var. acridum (Deuteromycotina: Hyphomycetes) in grasshopper cadavers in the Sahel. Unlike uninfected cadavers, which were rapidly scavenged, those infected with the fungus persisted in the environment for a number of weeks. The environmental factor most associated with cadaver disappearance was rainfall. The high environmental humidity associated with rainfall was also required for sporulation of the fungus on host cadavers, although the likelihood of sporulation differed between microsites. Characteristics of the infection profile from infective cadavers were investigated by the sequential exposure of uninfected hosts to sporulating cadavers in field cages. This experiment revealed that cadavers remained infective for > 30 days, with the net infectivity changing through time. The most likely explanation for these changes is climatic influences on both the fungus and host. High humidity was not required for infection. A measurement of the transmission coefficient between healthy hosts and sporulating cadavers in the field was obtained at a realistic density of infectious cadavers. This revealed a figure of 0.45 m2 day-1. Overall, these experiments show that following host death, M. anisopliae var. acridum can be persistent in the environment, sporulate on host cadavers and reinfect new hosts at a realistically low field density, although at least in arid or semi-arid areas, rainfall may be critical to the horizontal transmission of this pathogen.

Original languageEnglish (US)
Pages (from-to)69-76
Number of pages8
JournalEntomologia Experimentalis et Applicata
Volume100
Issue number1
DOIs
StatePublished - Jan 1 2001

Fingerprint

Sahel
infectivity
grasshopper
grasshoppers
pathogenicity
persistence
seasonal variation
fungus
sporulation
rain
rainfall
fungi
humidity
horizontal transmission
Deuteromycotina
experiment
Hyphomycetes
entomopathogenic fungi
Metarhizium anisopliae var. acridum
infection

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Insect Science

Cite this

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abstract = "Field-based experiments were conducted to evaluate the fate and infectivity of the entomopathogenic fungus Metarhizium anisopliae var. acridum (Deuteromycotina: Hyphomycetes) in grasshopper cadavers in the Sahel. Unlike uninfected cadavers, which were rapidly scavenged, those infected with the fungus persisted in the environment for a number of weeks. The environmental factor most associated with cadaver disappearance was rainfall. The high environmental humidity associated with rainfall was also required for sporulation of the fungus on host cadavers, although the likelihood of sporulation differed between microsites. Characteristics of the infection profile from infective cadavers were investigated by the sequential exposure of uninfected hosts to sporulating cadavers in field cages. This experiment revealed that cadavers remained infective for > 30 days, with the net infectivity changing through time. The most likely explanation for these changes is climatic influences on both the fungus and host. High humidity was not required for infection. A measurement of the transmission coefficient between healthy hosts and sporulating cadavers in the field was obtained at a realistic density of infectious cadavers. This revealed a figure of 0.45 m2 day-1. Overall, these experiments show that following host death, M. anisopliae var. acridum can be persistent in the environment, sporulate on host cadavers and reinfect new hosts at a realistically low field density, although at least in arid or semi-arid areas, rainfall may be critical to the horizontal transmission of this pathogen.",
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Seasonal patterns of persistence and infectivity of Metarhizium anisopliae var. acridum in grasshopper cadavers in the Sahel. / Arthurs, S. P.; Thomas, M. B.; Lawton, J. L.

In: Entomologia Experimentalis et Applicata, Vol. 100, No. 1, 01.01.2001, p. 69-76.

Research output: Contribution to journalArticle

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