Albert E. (“Bud”) Mayfield III

Research Entomologist, Acting Project Leader
Insects, Diseases, and Invasive Plants (RWU 4552)
USDA Forest Service
amayfield02@fs.fed.us

Education

  • B.S. in Biology, Yale University (1995)
  • M.S. in Forestry, West Virginia University (1997)
  • Ph.D. in Environmental and Forest Biology, State University of New York, College of Environmental Science and Forestry (2002)

Professional Experience

  • Forest Entomologist, Florida Division of Forestry from 2002-2009
  • Research entomologist, USDA-FS-SRS, 2010-present

Research Interests

My research focuses broadly on the biology and management of non-native invasive insects and insect-disease complexes.

Current Research

Hemlock woolly adelgid

Mortality of eastern hemlock (Tsuga canadensis) caused by hemlock woolly adelgid (Adelges tsugae, HWA) has been rapid in the Southern Appalachians during the last decade, often outpacing the ability of biological control agents to establish and spread. Improved management strategies and tools are need both to minimize impacts and to restore hemlock to heavily impacted forests (Vose et al. 2013a). My recent/current research on HWA includes:

  • Integrating biological and chemical control. In northern Georgia we demonstrated that the predator beetle Laricobius nigrinus can successfully establish, increase in number, and reduce adelgid densities on forest trees previously treated with imidacloprid insecticide. The insecticide treatment affords these trees prolonged crown health and, through the production of more new growth, the ability to eventually support more prey for Laricobius relative to untreated trees (Mayfield et al., in press). We are evaluating this integrated concept at a number of other sites in the southern Appalachians.
    Collaborators: University of North Carolina Asheville, University of Georgia, Virginia Tech, University of Tennessee, USFS Northern Research Station, USFS Forest Health Protection R8, other SRS 4552 scientists.
  • Artificial infestation techniques. With collaborators at North Carolina State University / Camcore, we developed and evaluated a novel method of infesting hemlock seedlings with adelgids, a technique that can be used for screening large numbers putatively adelgid resistant genotypes in a resistance breeding program for hemlock (Jetton et al. 2014).
  • Hemlock restoration. In a current project with North Carolina State / Camcore, we are evaluating silvicultural strategies (including overstory manipulation, chemical competition control, deer exclusion, and fertilization) to establish and promote new eastern hemlock stands in hardwood cove forests where HWA-induced mortality has been pronounced.

Redbay ambrosia beetle and laurel wilt

Laurel wilt is a destructive tree disease caused by a fungal vascular pathogen (Raffaelea lauricola) and spread by an invasive insect (Xyleborus glabratus, redbay ambrosia beetle, or RAB). Laurel wilt has virtually eliminated mature redbay (Persea borbonia) trees in many areas of the southeastern Coastal Plain and threatens commercial avocado production. My recent/current research on laurel wilt includes:

  • RAB host associations, utilization and location. To determine which species have most potential to perpetuate disease epidemics or serve as refugia for RAB populations, we determined the relative attractiveness and suitability to RAB for numerous native and cultivated Lauraceous species, including swampbay, silkbay, California bay laurel, sassafras, camphortree, avocado, and northern spicebush (Mayfield and Hanula 2012; Mayfield et al. 2013; Kendra et al. 2014). We also determined that diameter-related patterns in host mortality (Fraedrich et al. 20081) are partially explained by enhanced visual attraction of the RAB to larger diameter stems (Mayfield and Brownie 2013).
    Collaborators: USFS Forest Health Protection R8 and R5, Clemson University, USDA Agricultural Research Service, and other SRS 4552 scientists.
  • Management strategies for reducing laurel wilt impact. In a new research partnership with the University of Florida, we are exploring the use of coppice treatments as a means of reducing laurel wilt mortality and maintaining cultural uses of redbay, especially for the Seminole Indians and other Native American tribes in southern Florida. Treatments incorporate the use of a fungicide (propiconazole) infusion, of which we previously demonstrated efficacy for preventing laurel wilt (Mayfield et al. 20082).

Walnut twig beetle and thousand cankers disease

Thousand cankers disease (TCD) is caused by a bark beetle (Pityopthorus juglandis, walnut twig beetle) native to the extreme southwestern US and Mexico, and an associated fungal pathogen (Geosmithia morbida). The beetle is an introduced invasive pest in the upper western and eastern US where TCD is killing black walnut, one of the most commercially valuable hardwood timber species in the U.S. My recent/current research on TCD includes:

  • Phytosanitary treatments for walnut wood. To render previously-infested walnut wood safe for commercial transport, we developed a steam heat treatment schedule that kills the TCD causal organisms in walnut logs (Mayfield et al. 2014). We are currently developing a log fumigation schedule and methods for protecting treated wood from re-infestation, as well as evaluating the susceptibility of nursery stock to walnut twig beetle.
    Collaborators: University of Tennessee, USFS Forest Health Protection R8, USDA-APHIS-CPHST, other SRS 4552 scientists.
  • Pathogenic fungi as potential biological control agents. We are currently evaluating the susceptibility of the walnut twig beetle to known entomopathogens (Beauveria bassiana and Metarhizium brunneum) and the TCD pathogen to fungal mycoparasites (Trichoderma spp.).
    Collaborators: USDA Agricultural Research Service, University of Tennessee, Cornell University, and USFS Northern Research Station.