Albert K. Culbreath
Albert K. Culbreath was born in Hartselle, AL, in 1959. He is a graduate of Roane State Community College and Auburn University. In 1985, he received his M.S. degree in plant pathology and nematology from Auburn University and, in 1989, earned his Ph.D. degree in plant pathology with a minor in crop science and plant breeding from North Carolina State University. Following graduation, he was hired as an assistant professor in the Plant Pathology Department at the University of Georgia, Coastal Plains Experiment Station, Tifton, and began work on epidemiology and control of fungal foliar diseases of peanut and Tomato spotted wilt virus (TSWV) in peanut and tobacco. In 1994, he was promoted to associate professor.
Dr. Culbreath’s work on leaf spot diseases of peanut caused by Cercosporidium personatum and Cercospora arachidicola has dealt largely with chemical control, fungicide resistance management strategies, and integration of partial resistance to C. personatum with fungicide use for leaf spot control. Dr. Culbreath demonstrated that ‘Southern Runner’, a peanut cultivar with partial resistance to C. personatum, also has resistance to stem infections by the same pathogen. In cooperative efforts with Drs. Norman Minton and Tim Brenneman, Dr. Culbreath showed that resistance to late leaf spot was not affected by root-knot nematodes, but that partial resistance to Sclerotium rolfsii in ‘Southern Runner’ may be negated by nematode infestation.
Dr. Culbreath has been a leader in the integration of new systemic fungicides into peanut disease control systems, particularly related to strategies for preventing development of fungicide resistance in the pathogen populations. He demonstrated that tank mix combinations of low rates of ergosterol biosynthesis inhibiting fungicides with the protectant fungicide chlorothalonil provides excellent control of leaf spot, and he received a statutory patent for demonstrating synergistic effects of cyproconazole and chlorothalonil for leaf spot control. His work with use patterns and tank mixes of tebuconazole has resulted in significant improvements in control of leaf spot, southern stem rot, and Rhizoctonia limb rot of peanut. He further showed that tank mix combinations and/or alternations of benomyl with the protectant fungicide chlorothalonil can prolong the efficacy of benomyl in fields with populations of C. personatum that are benomyl insensitive. Dr. Culbreath’s work on thrips-vectored TSWV has resulted in progress toward a better understanding of this serious new problem for the southeastern United States. Although there are no tobacco cultivars available with resistance to TSWV, Dr. Culbreath has shown that there is resistance in some tobacco breeding lines that may provide a source for future cultivar development. By cooperative efforts with other scientists, he produced transgenic tobacco with the coat protein gene for TSWV.
In his work with TSWV on peanut, Dr. Culbreath worked very closely with virologists Drs. J. W. Demski and H. R. Pappu, entomologist Dr. J. Todd, and peanut breeders Drs. B. Branch and D. Gorbet. His efforts have led to the documentation of the slower epidemic development in the peanut ‘Southern Runner’ than in ‘Florunner’, the susceptible cultivar that in the mid-1980s was grown in over 90% of the peanut acreage in the southeastern United States. Dr. Culbreath showed that significant portions of the peanut population in a particular field were infected with TSWV but did not show symptoms. Dr. Culbreath received the Wallace K. Baily Award from the American Peanut Research and Education Society and the National Peanut Council Research and Education Award for this work. Due to the efforts of the Culbreath and Todd team in 1998, over two-thirds of the peanut acreage in Georgia and Florida will be planted to a peanut cultivar with a moderate level of field resistance to TSWV.
In cooperation with Drs. Todd and S. Brown, Dr. Culbreath has developed a spotted wilt management program that integrates the use of partial resistant cultivars, manipulation of planting date, increased seeding rates, and the use of phorate to greatly reduce incidence and severity of spotted wilt, even when any one of these factors individually would not provide sufficient control. They have developed a Spotted Wilt Risk Assessment Index by which growers and/or advisors calculate the relative risk of losses to spotted wilt based on a combination of the factors they plan to use.
Dr. Culbreath is the author or coauthor of over 50 refereed journal article and book chapters as well as numerous abstracts and other publications. He is currently the president of the APS Southern Division and a member of the American Peanut Research and Education Society and the Georgia Association of Plant Pathologists. He has chaired the APS Chemical Control and Placement committees and is a current member of the Host Plant Resistance Committee. Dr. Culbreath is an associate editor of Plant Disease.