Location: Tropical Crops and Germplasm Research
Title: Effects of invertebrate iridescent virus 6 in Phyllophaga vandinei and its potential as a biocontrol delivery system Authors
Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 3, 2010
Publication Date: April 8, 2011
Citation: Jenkins, D.A., Hunter, W.B., Goenaga, R.J. 2011. Effects of Invertebrate Iridescent Virus 6 in Phyllophaga and its potential as a biocontrol delivery system. Journal of Insect Science. Available: http://www.insectscience.org/II.44. Interpretive Summary: The May beetle is an important pest of fruit trees. Currently there are no suitable biological controls available for the management of this pest. We report that infection by an iridescent virus causes increased mortality (30% compared to 0%) and results in dramatically altered behavior that reduces the impact of the pest on host crops. Infected individuals do not feed or reproduce. Furthermore, frass of individuals that survive infection aids in spreading infection to healthy individuals. This suggests that the iridovirus may be used as a “delivery” system for a more potent or genetically altered virus, allowing infected individuals to contaminate target insect populations.
Technical Abstract: Invertebrate iridescent virus 6 (IIV6) was determined to cause infection in Phyllophaga vandinei Smyth, through a range of modes of transmissions. This is the first evidence of IIV6 infection in P. vandinei, which caused both patent and sub-lethal covert infections in larvae and adults. Mortality rates were determined to be ~30% when virus inoculum was injected into larvae or adults. Adults injected with virus showed dramatically altered behaviour; injected beetles were not observed feeding or mating and fewer adults were observed emerging from the soil at night when compared with adults injected with buffer or adults that were not injected. Tissue collected from infected adults resulted in infection when injected in healthy adults, as confirmed with PCR. PCR also confirmed that frass of infected larvae and adults contained virus and when reconstituted frass was injected into healthy adults or larvae they become infected. Non virus exposed, healthy adults were infected by coming into contact with soil or plant material that had been exposed to infected adults as much as two weeks prior to introduction of healthy adults. Although relatively low mortality resulted when adults or larvae were injected with the virus, the demonstration of horizontal transmission, potentially through frass of infected individuals, identifies a mode of transmission which may be exploited to use the virus as a potential management tool to reduce P. vandinei populations.