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United States Department of Agriculture

Agricultural Research Service

Title: Effects of in Vitro Passage of Beauveria Bassinaa on Virlence to Bemisia Argentifolii

Authors
item Brownbridge, Michael - UNIVERSITY OF VERMONT
item Costa, Scott - UNIVERSITY OF VERMONT
item Jaronski, Stefan

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 26, 2001
Publication Date: May 1, 2001
Citation: BROWNBRIDGE, M., COSTA, S., JARONSKI, S. EFFECTS OF IN VITRO PASSAGE OF BEAUVERIA BASSINAA ON VIRLENCE TO BEMISIA ARGENTIFOLII. JOURNAL OF INVERTEBRATE PATHOLOGY. 2001. V. 77. ISSUE 4. P. 280-283.

Interpretive Summary: There seems to be a general consensus that entomopathogenic hyphomycetes will lose their ability to infect insects when routinely subcultured on artificial media. Published effects of repeated in vitro subculture on virulence and morphological characteristics of entomopathogenic fungi appear to vary considerably among isolates and species. In the current study we assessed effects of repeated in vitro passage on the virulence of the B. bassiana GHA strain, the active ingredient in the commercial products BotaniGard and Mycotrol (Mycotech Corp., Butte, MT). The fungi were assayed against neonate and 2-d old (pre-molt) Bemisia argentifolii ('whitefly') nymphs infesting bean leaves (var. Royal Burgundy) rooted in Oasis rooting cubes (Smithers-Oasis USA, Kent, OH). Two doses (4.0x107 and 2.5x106 viable conidia per ml of 0.02% Silwet L77) were used to enhance the possibility of detecting small changes in virulence that could be missed if only a single dose was used. No significant differences were detected between mortality and infection rates for fungi passaged 1, 5, 10 or 15 times at either test concentration. The results of the current study strongly indicate that the genetic factors controlling pathogenicity in the B. bassiana GHA strain are stable enough to facilitate limited repeated transfer and culture on artificial media, such as during the mass-production process, without affecting the virulence of the isolate.

Technical Abstract: There seems to be a general consensus that entomopathogenic hyphomycetes will lose their ability to infect insects when routinely subcultured on artificial media. Published effects of repeated in vitro subculture on virulence and morphological characteristics of entomopathogenic fungi appear to vary considerably among isolates and species. In the current study we assessed effects of repeated in vitro passage on the virulence of the B. bassiana GHA strain, the active ingredient in the commercial products BotaniGard and Mycotrol (Mycotech Corp., Butte, MT). The fungi were assayed against neonate and 2-d old (pre-molt) Bemisia argentifolii ('whitefly') nymphs infesting bean leaves (var. Royal Burgundy) rooted in Oasis rooting cubes (Smithers-Oasis USA, Kent, OH). Two doses (4.0x107 and 2.5x106 viable conidia per ml of 0.02% Silwet L77) were used to enhance the possibility of detecting small changes in virulence that could be missed if only a single dose was used. No significant differences were detected between mortality and infection rates for fungi passaged 1, 5, 10 or 15 times at either test concentration. The results of the current study strongly indicate that the genetic factors controlling pathogenicity in the B. bassiana GHA strain are stable enough to facilitate limited repeated transfer and culture on artificial media, such as during the mass-production process, without affecting the virulence of the isolate.

Last Modified: 12/18/2014
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