Evaluating the effects of a biopesticide on populations of the variegated grasshopper, Zonocerus variegatus

A field trial was conducted to investigate the efficacy of an oil formulation of the fungal entomopathogen, Metarhizium flavoviride, for control of the variegated grasshopper, Zonocerus variegatus. The results of the trial showed a significant reduction in grasshopper populations following spray app...

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Main Authors: Thomas, M.B., Langewald, J., Wood, S.N.
Format: Journal Article
Language:Inglés
Published: 1997
Subjects:
Online Access:https://hdl.handle.net/10568/98609
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author Thomas, M.B.
Langewald, J.
Wood, S.N.
author_browse Langewald, J.
Thomas, M.B.
Wood, S.N.
author_facet Thomas, M.B.
Langewald, J.
Wood, S.N.
author_sort Thomas, M.B.
collection Repository of Agricultural Research Outputs (CGSpace)
description A field trial was conducted to investigate the efficacy of an oil formulation of the fungal entomopathogen, Metarhizium flavoviride, for control of the variegated grasshopper, Zonocerus variegatus. The results of the trial showed a significant reduction in grasshopper populations following spray application compared with non-treated controls. 2. Further studies revealed that there was significant movement of insects into and out of the treated plots during the course of the experiment, and that the pathogen spray residue remained infective for several days after application. 3. To help interpret these data and link them more closely to the basic population counts, insect-pathogen models were developed which accounted for the effects of secondary pick up of spores, insect movement and mortality on disease levels observed in the field. These revealed that contact with spores from the spray residue was an important route of infection for insects moving into the treated areas after spraying. They also revealed that there was an increase in disease incubation periods in the field compared with the laboratory; this slowed mortality rates. 4. Overall, the combination of laboratory, field and theoretical studies suggested that the total impact of the M. fiavoviride-based biopesticide was very high. This combination of techniques revealed considerably more information than the indi- vidual indicators of efficacy commonly used to assess biopesticide applications. As such, this study demonstrates how basic ecological approaches can be of value in an applied context, helping to provide a link between laboratory and field studies, and aiding the interpretation of complex field trial results
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spelling CGSpace986092025-01-27T15:00:52Z Evaluating the effects of a biopesticide on populations of the variegated grasshopper, Zonocerus variegatus Thomas, M.B. Langewald, J. Wood, S.N. entomogenous fungi biological control pathogens grasshoppers models A field trial was conducted to investigate the efficacy of an oil formulation of the fungal entomopathogen, Metarhizium flavoviride, for control of the variegated grasshopper, Zonocerus variegatus. The results of the trial showed a significant reduction in grasshopper populations following spray application compared with non-treated controls. 2. Further studies revealed that there was significant movement of insects into and out of the treated plots during the course of the experiment, and that the pathogen spray residue remained infective for several days after application. 3. To help interpret these data and link them more closely to the basic population counts, insect-pathogen models were developed which accounted for the effects of secondary pick up of spores, insect movement and mortality on disease levels observed in the field. These revealed that contact with spores from the spray residue was an important route of infection for insects moving into the treated areas after spraying. They also revealed that there was an increase in disease incubation periods in the field compared with the laboratory; this slowed mortality rates. 4. Overall, the combination of laboratory, field and theoretical studies suggested that the total impact of the M. fiavoviride-based biopesticide was very high. This combination of techniques revealed considerably more information than the indi- vidual indicators of efficacy commonly used to assess biopesticide applications. As such, this study demonstrates how basic ecological approaches can be of value in an applied context, helping to provide a link between laboratory and field studies, and aiding the interpretation of complex field trial results 1997 2018-12-19T07:00:38Z 2018-12-19T07:00:38Z Journal Article https://hdl.handle.net/10568/98609 en Limited Access Thomas, M.B., Langewald, J. & Wood, S.N. (1996). Evaluating the effects of a biopesticide on populations of the variegated grasshopper, Zonocerus variegatus. Journal of Applied Ecology, 33(6), 1509-1516.
spellingShingle entomogenous fungi
biological control
pathogens
grasshoppers
models
Thomas, M.B.
Langewald, J.
Wood, S.N.
Evaluating the effects of a biopesticide on populations of the variegated grasshopper, Zonocerus variegatus
title Evaluating the effects of a biopesticide on populations of the variegated grasshopper, Zonocerus variegatus
title_full Evaluating the effects of a biopesticide on populations of the variegated grasshopper, Zonocerus variegatus
title_fullStr Evaluating the effects of a biopesticide on populations of the variegated grasshopper, Zonocerus variegatus
title_full_unstemmed Evaluating the effects of a biopesticide on populations of the variegated grasshopper, Zonocerus variegatus
title_short Evaluating the effects of a biopesticide on populations of the variegated grasshopper, Zonocerus variegatus
title_sort evaluating the effects of a biopesticide on populations of the variegated grasshopper zonocerus variegatus
topic entomogenous fungi
biological control
pathogens
grasshoppers
models
url https://hdl.handle.net/10568/98609
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