Chronic effects and horizontal transmission of Metarhizium anisopliae strain QS155 infection in the sweet potato weevil, Cylas formicarius (Coleoptera: Brentidae)

Dotaona, Ronnie and Wilson, Bree A. L. and Stevens, Mark M. and Holloway, Joanne and Ash, Gavin J. (2017) Chronic effects and horizontal transmission of Metarhizium anisopliae strain QS155 infection in the sweet potato weevil, Cylas formicarius (Coleoptera: Brentidae). Biological Control, 114. pp. 24-29. ISSN 1049-9644

Abstract

Cylas formicarius is a major pest of sweetpotato in Papua New Guinea. In this study, the chronic effects of infection with Metarhizium anisopliae strain QS155 in adult C. formicarius were investigated. Female fecundity was significantly reduced in treatments where females were infected directly and maintained in pairs with either infected or uninfected males, and to a statistically equivalent level (51%) when initially uninfected females were caged with infected males. A significant increase in the proportion of eggs left exposed outside the host plant occurred in response to either direct or indirect maternal exposure to M. anisopliae. The hatchability of eggs fully enclosed by host plant tissues was also significantly reduced by exposure of females to M. anisopliae; together these factors led to a total decline in reproductive success of 69%-80%. These results demonstrate that a conidial concentration of M. anisopliae strain QS155 well below that required for rapid host mortality adversely affects reproductive and behavioural traits in adult C. formicarius. When groups of C. formicarius were held together for 12 days after either all males, all females, or just a proportion of males were initially inoculated, clear evidence of horizontal transmission was obtained. In both males and females mortality arising from horizontal transmission was statistically equivalent to mortality levels when individuals of the same sex had been directly infected. Exposure to sporulating adult cadavers also caused significant mortality to uninfected SPW adults, and M. anisopliae was recovered from weevils that died following exposure to infected cadavers.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to published version, in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: Current - Institute for Life Sciences and the Environment - Centre for Crop Health (24 Mar 2014 -)
Faculty/School / Institute/Centre: Current - Institute for Life Sciences and the Environment - Centre for Crop Health (24 Mar 2014 -)
Date Deposited: 04 Aug 2019 23:47
Last Modified: 10 Sep 2019 02:05
Uncontrolled Keywords: sweet potato; Cylas formicarius; Metarhizium anisopliae; fecundity; horizontal transmission
Fields of Research : 07 Agricultural and Veterinary Sciences > 0703 Crop and Pasture Production > 070308 Crop and Pasture Protection (Pests, Diseases and Weeds)
Socio-Economic Objective: B Economic Development > 82 Plant Production and Plant Primary Products > 8202 Horticultural Crops > 820299 Horticultural Crops not elsewhere classified
Identification Number or DOI: 10.1016/j.biocontrol.2017.07.008
URI: http://eprints.usq.edu.au/id/eprint/35643

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