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United States Department of Agriculture

Agricultural Research Service

Title: Grower Adoptable Formulations of the Entomopathogenic Fungus Metarhizium Anisopliae (Ascomycota: Hypocreales) for Sugarbeet Root Maggot Management

Authors
item Campbell, Larry
item Boetel, Mark - NORTH DAKOTA STATE UNIV
item Jonason, Nyle
item Jaronski, Stefan
item Smith, Larry - UNIV OF MINNESOTA

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 10, 2006
Publication Date: July 15, 2006
Repository URL: http://hdl.handle.net/10113/691
Citation: Campbell, L.G., Boetel, M., Jonason, N.B., Jaronski, S., Smith, L. 2006. Grower-Adoptable Formulations of the Entomopathogenic Fungus Metarhizium anisopliae (Ascomycota: Hypocreales) for Sugarbeet Root Maggot (Diptera: Ulidiidae) Management. Environmental Entomology. 35(4):986-991.

Interpretive Summary: In many North American sugarbeet production regions, sugarbeet root maggot management relies almost exclusively on two organophosphate insecticides. The possibility that insecticide resistant root maggot strains might develop or the insecticides could become unavailable due to environmental concerns prompted a search for biological control agents that might supplement or replace the widely used chemical insecticides. Based on some preliminary studies, it was decided to further investigate the insect pathogenic fungus Metarhiziium anisopliae as a potential root maggot management option. A Metarhizium strain with virulence to the root maggot in laboratory investigations was applied to field plots at four site as a corn meal-based planting-time granule, as a spray timed to coincide with peak adult fly activity, or a combination of both. Three rates of Metarhizium, 4X1012 (1X), 8X1012 (2x), and 1,6X1013 (4x) conidia ha-1, were applied as granules; the spray was applied at the 1X rate only. The average sucrose yield achieved with the 4X rate and a significant linear sucrose yield response in relation to Metarhizium concentration confirmed the entomopathogenic capability of this Metarhizium strain under field conditions. Each multiple of M. anisopliae granules applied affected an increase of approximately 170 kg sucrose ha-1. The Metarhizium strain used in this study was less effective than conventional insecticides at preventing early season stand loss due to high infestations of root maggot early in the season. It is concluded that with additional research, fungal bioinsecticides could potentially be incorporated into management programs to complement chemical seed treatments, planting-time insecticides (possibly at reduced rates), or postemergence insecticides for root maggot adult and larval control.

Technical Abstract: In many North American sugarbeet (Beta vulgaris L.) production areas, sugarbeet root maggot (Tetanops myopaeformis Röder) management relies almost exclusively on organophosphate insecticides. The possibility that organophosphate-resistant root maggot strains might develop or the insecticides could become unavailable due to environmental concerns prompted a search for biological control agents that might supplement or replace the widely used conventional chemical insecticides. Based on preliminary studies, it was decided to further investigate the entomopathogenic fungus Metarhizium anisopliae (Metschnikoff) Sorokin as a potential management option for bioinsecticidal control of T. myopaeformis. American Type Culture Collection (ATCC) accession No. 62176, a strain of M. anisopliae with demonstrated virulence to root maggot larvae in previous laboratory investigations, was applied to field plots at four sites during 2001 and 2002 as a corn meal-based planting-time granule, a spray timed to coincide with peak adult fly activity, or a combination of both. Three rates of the fungus, 4X1012 (1X), 8X1012 (2X), and 1.6X1013 (4X) conidia ha-1, were applied as granules, and the spray was applied at the 1X rate only. A significant linear response in sucrose yield in relation to M. anisopliae granule application rate confirmed the entomopathogenic capability of this strain under field conditions. Each multiple of M. anisopliae granules applied affected an increase of approximately 170 kg sucrose ha-1. The Metarhizium strain used in this study was less effective than conventional insecticides at preventing early season stand loss due to high infestations of root maggot early in the season. It is concluded that with additional research, fungal bioinsecticides could potentially be incorporated into management programs to complement chemical seed treatments, planting-time insecticides (possibly at reduced rates), or postemergence insecticides for T. myopaeformis adult and larval control.

Last Modified: 10/25/2014