Transgenic entomopathogenic fungi in the semi-field

Here we report initial findings testing the mosquitocidal efficacy of a Metarhizium strain (Mr-hybrid) engineered to express an insect-specific spider neurotoxin (hybrid) and GFP. The experiments are being conducted in a multi-chambered Malaria sphere (a contained near-natural environment), constructed for the purpose in a region of Burkina Faso where malaria is endemic. We used the sphere to test a variety of low technology treatment protocols that could be used routinely by householders and found that suspending Metarhizium in locally produced sesame oil and spreading that on netting or black sheets achieves a long term effect in the sphere. We compared the persistence and virulence of Mr-Hybrid with a strain of wild-type virulence expressing RFP (Mr-RFP), and found that Mr-Hybrid killed anopheline mosquitoes in half the time and at much lower spore doses so the effective persistence was increased. We also compared Mr-Hybrid and Mr-RFP for their ability to control mosquito population’s confirming that our semi-field results reproduce results from the laboratory. This coordinated, NIH funded, international effort represents an important step in the progression of transgenic mosquito control technologies into field application. It offers the opportunity to explore public opinion of genetically modified organisms and could provide a precedent for clearing social and scientific hurdles to introducing promising vector control strategies into the field.