What a well-deserve honor to see UC Davis Distinguished Professor Walter Leal receive the 2026 Applied Chemical Ecology Award from the International Society of Chemical Ecology (ISCE) for his applied research targeting insect pests that damage plants, spread diseases, and destroy crops.
Leal, a member of the Department of Molecular and Cellular Biology faculty, is a former chair of the UC Davis Department of Entomology (now the UC Davis Department of Entomology). He is widely celebrated for his work on insect chemical communication involving mosquitoes, navel orangeworms, Asian citrus psyllids, citrus borer moth and other pests.
Leal delivered his Applied Chemical Ecology Award presentation at the recent ISCE conference, hosted by Cornell University. He touched on his upbringing in Brazil; his education in Brazil, Japan and the United States; his career; and his research that has led to 23 patents.
ISCE established the award to recognize career achievements by outstanding chemical ecologist for their “significant contribution in developing novel semiochemical-based technologies for advancing practical applications in chemical ecology.”
“Walter is, without a doubt, one of the foremost authorities on the integration of chemical ecology fundamental research (molecular, biochemical, and physiological interactions among insects and between insects and plants) and translational research culminating in numerous patents, on the identification of numerous semiochemicals,” wrote nomination team leader Professor Coby Schal, the Blanton J. Whitmire Distinguished Professor of the Department of Entomology and Plant Pathology, North Carolina State University, and a former ISCE president.
'One of the Best in the World'
“His chemical ecology research and prospecting program is one of the best in the world,” Schal wrote. “Over the past 32 years, Walter has coupled excellence in research and teaching with extraordinary service to ISCE, Entomological Society of America and the scientific community in general.”
Walter’s research, in the last three decades, has addressed almost every aspect of chemical ecology and both fundamental and translational entomology. With 230 papers (and 21 chapters and review articles), most of which in top-tier journals (19 in Proceedings of the National Academy of Sciences), Walter has published on mites, thrips, scarabs, bugs, aphids, cockroaches, moths, wasps, mosquitoes, and plants. I cannot think of another chemical ecologist (including members of various U.S. National Academies of Sciences) that has demonstrated such curiosity, creativity, and breadth so early in their career and for so long.”
Leal earlier received ISCE’s Silver Medal Award and the Silverstein-Simeone Award, as well as the Nan-Yao Su creativity award from the Entomological Society of America (ESA). Leal is a fellow of ESA, the American Association for the Advancement of Science, and the Royal Entomological Society, among other honors.
Among Leal’s many accomplishments, Schal mentioned that
- Leal identified the complex sex pheromone system of the navel orangeworm, a key agricultural pest responsible for multi-million crop damage annually in California. His work, now being deployed in the agricultural field, disrupts chemical communication and controls the navel orangeworm population through mating disruption.
- He and his lab discovered DEET’s mode of action, something that had puzzled and eluded scientists since the U.S. Army patented it in 1946. Scientists long surmised that DEET works by masking the smell of the host, or jamming the insect’s senses, thus interfering with its ability to locate a host. Not so: in groundbreaking research, the Leal lab found that mosquitoes can indeed smell the chemical repellent but they dislike it so intensely that they avoid it. More than 200 million people use DEET to ward off disease vectors.
- He and his lab identified the dominant odor naturally produced in humans and birds that attracts the blood-feeding Culex mosquitoes, which transmit West Nile virus and other life-threatening diseases. This research explains why mosquitoes shifted hosts from birds to humans, why the virus is so easily transmitted, and paves the way for key developments in mosquito and disease control.
In describing Leal as “one of the most energetic and generous scientists I know,” Schal pointed out that Leal organizes international and area conferences and symposia, “hubs for informal discussions and new collaborations.” He mentioned that Leal organized a symposium on Insect Olfaction and Taste in 24 Hours Around the Globe that highlighted entomological research in chemoreception and its application in public health, veterinary, and agricultural integrated pest management.
Native of Brazil
A native of Brazil, Leal received his bachelor's degree in chemical engineering from the Federal University of Pernambuco in Recife, a master's in agricultural chemistry from Mie University in Japan, and a Ph.D. in applied biochemistry from the University of Tsukuba in Japan.
He joined the UC Davis Department of Entomology in 2000, after serving as head of the Laboratory of Chemical Prospecting, National Institute of Sericultural and Entomological Science (NISES), Ministry of Agriculture, Forestry, and Fisheries, Japan
Leal is the first UC Davis faculty member to be honored by the Academic Senate with all three of its teaching, public service and research awards. He received the 2020 Distinguished Teaching Award for undergraduate teaching, the 2022 Distinguished Scholarly Public Service Award, and the 2024 Faculty Distinguished Research Award.
Leal recapped the ISCE meeting in a YouTube video posted at https://www.youtube.com/live/JrP35Y-d07E.
(See more on the UC Davis Department of Entomology and Nematology website.)
Cover image: UC Davis Distinguished Professor Walter Leal.