Development of an automated VOC dispersal device for contact-independent control of fungi

Use of volatile organic compounds (VOCs) with a newly-developed dispersal device may present many advantages over traditional methods for the control of fungi that colonize areas difficult or impossible to directly access. This research focuses primarily on inhibition of Pseudogymnoascus destructans, a newly-discovered ascomycetous fungus and the etiological agent of a deadly epidemic among North American bats, known as White-Nose Syndrome (WNS). As bats are known to hibernate in areas that are challenging to access, it is believed that contact-independent antagonism may be a viable option for in and ex situ treatment of WNS. Several previously-identified Pseudomonas- and Bacillus-produced antifungal VOCs were investigated and demonstrated their inhibitory effect through contact-independent antagonism. The development of a device was undertaken to autonomously disperse these antimicrobial compounds, as microscopic vapor droplets (0.5 - 5 µm diameter), to facilitate rapid evaporation in order to attain a specific gaseous concentration. Functioning prototypes of the device have demonstrated accurate dispersal of VOCs and VOC formulations. Additionally, a toxicity study with this device and a highly-effective anti-P. destructans VOC formulation on torpid bats (n=37) yielded favorable results. Necropsies, with specific attention to respiratory tissue, indicated no significant detrimental effects. In addition to disease management, this device has potential to serve a much broader range of uses with microbial control. Furthermore, the design allows for a wide variety of essential oils, VOCs, and VOC formulations to be used, and with the addition of an enclosure and batteries, prolonged use in harsh or remote environments is possible.