Effective Control of a Field Population of Helicoverpa armigera by Using the Small RNA Virus Helicoverpa armigera Stunt Virus (Tetraviridae: Omegatetravirus)

The first comprehensive field trial using an insect small RNA virus as a control agent on a cropping system was conducted with the Helicoverpa armigera stunt virus (family Tetraviridae, genus Omegatetravirus, HaSV). The virus was semipurified, quantified, and applied at two rates, 4 × 1015 and 4 × 1...

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Bibliographic Details
Published in:Journal of economic entomology 2005-12, Vol.98 (6), p.1839-1847
Main Authors: Christian, Peter D., Murray, David, Powell, Rebeccah, Hopkinson, Jamie, Gibb, Nerida N., Hanzlik, Terry N.
Format: Article
Language:English
Subjects:
Animals
application rate
baculovirus
BIOLOGICAL AND MICROBIAL CONTROL
biological control agents
biopesticide
Helicoverpa armigera
Helicoverpa armigera stunt virus
insect control
Insect Control - methods
Insect Viruses
larvae
Moths - virology
Nucleopolyhedrovirus
pesticide persistence
population density
RNA Viruses
Sorghum
Sorghum bicolor
tetravirus
Time Factors
viral insecticides
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Summary:The first comprehensive field trial using an insect small RNA virus as a control agent on a cropping system was conducted with the Helicoverpa armigera stunt virus (family Tetraviridae, genus Omegatetravirus, HaSV). The virus was semipurified, quantified, and applied at two rates, 4 × 1015 and 4 × 1014 virus particles/ha, with minimal formulation on sorghum against the bollworm Helicoverpa armigera (Hübner). For comparison, a commercial preparation of Helicoverpa zea single- nucleopolyhedrovirus (HzSNPV, Gemstar) was applied at the same time at 9.27 × 1011 polyhedral inclusion bodies/ha. The HaSV application rates were determined by a novel procedure using laboratory LC50 bioassay data for HaSV and HzSNPV and calibration to the known field application rate of the HzSNPV. The baculovirus and the higher rate of HaSV produced statistically equivalent reductions in the larval populations of around 50% at both 3 and 6 d postapplication (dpa) compared with untreated plots. The 10-fold lower rate of HaSV reduced the larval population by 50% at 3 dpa and ≈30% at 6 dpa. Persistence of HaSV over a 72-h period was found to be similar to that of HzSNPV, although the amount of HaSV available on the sorghum heads increased at 130 h postapplication, due most likely to dispersal of newly produced virus from cadavers and frass. The results from this trial indicate that HaSV could be used as an effective biopesticide for the control of H. armigera in sorghum and the ramifications for its broader use are discussed.
ISSN:0022-0493
1938-291X
0022-0493
DOI:10.1603/0022-0493-98.6.1839