He received his Ph.D. in Plant Physiology and Biochemistry from Duke University. He spent 21 years in weed management-oriented research with the Agricultural Research Service (ARS) of USDA. He was Research Leader of the ARS Natural Product Utilization Research Unit at the National Center for Natural Products Research (NCNPR) in Oxford, Mississippi.
He is an internationally recognized expert on weed management and biopesticides. His research has led to significant findings on how herbicides work and the potential of using natural products in weed and pest management. His extensive scientific production includes more than 400 peer-reviewed publications and a dozen of co-written or edited books.
He has been active in professional organizations and editorial boards of journals. He was President of the WSSA, the IWSS, and International Allelopathy Society (IAS), as well as Chair of the Agrochemical Division (AGRO) of the ACS. His awards include fellow of AAAS, AGRO, WSSA, and ACS, as well as winner of the Molisch Award (IAS), inductee into the ARS Science Hall of Fame, and recipient of an honorary doctorate from the University of the Basque Country.
He is currently Editor-in-Chief of the journal Pest Management Science and Adjunct Research Professor at the NCNPR of the University of Mississippi.