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United States Department of Agriculture

Agricultural Research Service

Research Project: IPM-BASED STRATEGIES FOR BIOLOGICAL CONTROL OF GREENHOUSE AND VEGETABLE CROP PESTS

Location: Biological Integrated Pest Management Unit

Title: Beauveria bassiana, Metarhizium anisopliae, and Metarhizium anisopliae var. acridum conidia: tolerance to imbibitional damage

Authors
item Faria, Marcos -
item Hajek, Ann -
item Wraight, Stephen

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 24, 2009
Publication Date: August 16, 2009
Citation: Faria, M., Hajek, A.E., Wraight, S.P. 2009. Beauveria bassiana, Metarhizium anisopliae, and Metarhizium anisopliae var. acridum conidia: tolerance to imbibitional damage. Meeting Abstract. 42:80.

Technical Abstract: When dry fungal cells are immersed in water, rapid imbibition (water uptake) may compromise the plasma membrane, killing the cell. This study investigated the impact of imbibitional damage (measured in terms of reduced viability) on Beauveria bassiana (Bb), Metarhizium anisopliae (Ma) and M. anisopliae var. acridum (Mac) conidia dried/hydrated to five different water activities prior to immersion in water at temperatures varying from 0.5 to 33 degrees Celsius. Imbibitional damage to conidia of all species occurred rapidly, with no differences in viability observed following immersion for 2 vs. 60 min. For Bb, initial water activity had little or no effect on germination following immersion at temperatures around 15 degrees Celsius. However, following immersion at 0.5 degrees Celsius, dry conidia retained only 43-65 percent viability compared to 87 percent for conidia that were partially or nearly fully hydrated prior to immersion. For Mac, immersion of dry conidia at temperatures around 15 degrees Celsius significantly reduced viability, but hydrated conidia were injured only at 0.5 degrees Celsius. Dry Ma conidia showed reduced viability after immersion at all temperatures, and viability dropped to around 1 percent and 27-41 percent following immersion in water chilled to 0.5 and 15 degrees Celsius, respectively. Immersion of dry Ma conidia at 25 and 33 degrees Celsius resulted in viabilities of 66-75 percent and 86 percent, respectively. Viabilities observed following immersion of partially hydrated Ma conidia were greater than those observed after immersion of dry conidia at temperatures less than 33 degrees Celsius, but highest viabilities (91-94 percent) were observed after immersion of fully hydrated conidia regardless of temperature. Formulation of dry Ma conidia in paraffinic oil provided considerable protection from imbibitional damage.

Last Modified: 9/2/2014
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