Journal of Environmental Biology

In vivo interactions of entomopathogenic fungi, Beauveria spp.

and Metarhizium anisopliae with selected opportunistic

soil fungi of sugarcane ecosystem

Author Details

N. Geetha

(Corresponding author)

Sugarcane Breeding Institute, Indian Council of Agricultural Research, Coimbatore - 641007, India

e-mail: mvsbi@yahoo.com

M. Preseetha

Sugarcane Breeding Institute, Indian Council of Agricultural Research, Coimbatore - 641007, India

K. Hari

Sugarcane Breeding Institute, Indian Council of Agricultural Research, Coimbatore - 641007, India

G. Santhalakshmi

Sugarcane Breeding Institute, Indian Council of Agricultural Research, Coimbatore - 641007, India

K. Subadra Bai

Sugarcane Breeding Institute, Indian Council of Agricultural Research, Coimbatore - 641007, India

Publication Data

Paper received:

27 November 2010

Revised received:

07 April 2011

Accepted:

23 April 2011

Abstract

In the present study, the interactions of entomopathogenic fungi viz., Beauveria bassiana, Beauveria brongniartii and Metarhizium anisopliae among themselves and three other opportunistic soil fungi from the sugarcane ecosystem namely, Fusarium saachari, Aspergillus sp. and Penecillium sp. were assayed in vivo against Galleria mellonella larvae. The tested fungi were co-applied on IV instar G. mellonella @ 1x 10⁷ ml^-1, in combinations of two, at the interval of 24 hrs either preceding or succeeding each other to assess their efficacy and sporulation rates. Results showed that often mortality rates did not correspond to the spore harvest of the mortality agent and presence of other fungus may be antagonistic. The efficacy of B. bassiana (90%) and B. brongniartii (100%) was not enhanced further but was negatively affected in most combinations with other fungi. In case of M. anisopliae compatibility was higher, resulting in higher mortality by application of B. bassiana before (100%) or after (83.3%) M. anisopliae than when it was applied alone (70%). During sporulation, B. bassiana faced the most intense competition from M. anisopliae (2.75x10⁶ larva^-1) and enhancement due to F. sacchari irrespective of sequence of application. In case of B. brongniartii, sporulation was lowest in the combination of B. brongniartii preceding M. anisopliae (1.83 x10⁶ larva^-1) and B. brongniartii succeeding B. bassiana (1.58x10⁶ larva^-1). Of all fungi tested, except F. sacchari (65.33 x 10⁶ larva^-1) all the other species affected sporulation of M. ansiopliae with the least in treatment of B. bassiana application following M. anisopliae. Similar kind of interaction was observed during sporulation of soil fungi when combined with entomopathogenic fungi, though individually they could not cause mortality of larvae. ?

Key words

Beauveria bassiana, Beauveria brongniartii, Metarhizium anisopliae, Galleria mellonella, In-vivo interaction, Opportunistic fungi

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