Research Plant Pathologist
Mark Hilf, Ph.D.
Dr. Hilf's research encompasses virus and virus-like pathogens of citrus. Research is conducted to answer questions about the basic biology of citrus viruses and the diseases they cause. Currently, research is focused on citrus tristeza virus (CTV) with an emphasis on understanding the genetic diversity of CTV to provide better tools for diagnosis and characterization. Molecular genetic tools have been created to complement existing serological and biological methods of CTV strain identification. Work is also underway to find and characterize novel sources of resistance to CTV. Research on the use of viroids as dwarfing agents, as well as research on a potentially new disease called grapefruit flaky bark is conducted collaboratively with other ARS scientists as well as scientists at the University of Florida. A USHRL based collection of viral pathogens, including CTV, citrus viroids, citrus tatterleaf virus, as well as several strains of citrus psorosis virus, is maintained to provide necessary research material. In addition to endemic citrus viruses, research is conducted under quarantine on the characterization of citrus viruses exotic to US citrus growing areas, as a means to develop detection methods for these pathogens to prevent their introduction and to identify them should they be inadvertently introduced into US citrus areas.