Walter Leal smiling and gesturing at wooden lectern (photograph) — UC Davis Distinguished Professor Walter Leal received 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. Here he delivers his presentation at the recent ISCE meeting hosted at Cornell University.

Walter Leal Receives 2026 Applied Chemical Ecology Award

Presented at ISCE Conference Held at Cornell

by Kathy Keatley Garvey
September 08, 2026

Walter Leal gesturing at lectern bearing Cornell University seal — UC Davis Distinguished Professor Walter Leal speaking at the International Society of Chemical Ecology conference, where he received the 2026 Applied Chemical Ecology Award.

UC Davis Distinguished Professor Walter Leal of the Department of Molecular and Cellular Biology, College of Biological Sciences, is the recipient of 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 former chair of the UC Davis Department of Entomology—and celebrated for his work on insect chemical communication involving mosquitoes, navel orangeworms, Asian citrus psyllids, citrus borer moth and other pests--delivered his Applied Chemical Ecology Award presentation at the recent ISCE conference, held at 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.”

“From the onset of my career, I have readily adopted new technologies and typically used multidisciplinary approaches to tackle complex problems,” commented Leal, an elected member of the National Academy of Sciences and the National Academy of Inventors. (See https://www.youtube.com/watch?v=RIODgk8IN54)

'A Foremost Authority'

“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.

“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.”

Schal related that “around 1990, Walter meteorically emerged onto the chemical ecology and entomology scene! Chemical signaling is fundamental to all life forms including microbes, plants, and animals, and chemical cues allow animals to appraise their environment, to detect food, toxins, prey, predators and pathogens, to identify kin, and to evaluate and bias mate choice decisions of potential reproductive partners.”

“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.

Article: Mosquitoes smell and avoid DEET, article metadata and small bar chart — Screenshot of PNAS Publication

'Publications of Great Impact'

“Walter has an incredible knack for combining chemical ecology with broader disciplines of biology,” Schal related. “He effortlessly bridges field-based approaches and crop protection with molecular approaches and structural biology. Bridging these seemingly disparate approaches, Walter conducts integrative physiological work that defines the cutting edge of the science. What’s more, his publications at both ends of this spectrum are of great impact to both applied entomology and fundamental biology…The impacts of his technical innovations and scholarship are huge--he made possible many important discoveries of pheromones, plant volatiles, and microbial and fungal metabolites that are used extensively in IPM programs.”

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.

Asian Citrus Psyllid and Navel Orangeworm

In his letter of support, Cam Oehlschlger, vice president of Chemtica Internacional, Costa Rica, lauded Leal’s work on the Asian citrus psyllid and the navel orangeworm (NOW). “His work on Asian citrus psyllid attractants yielded new attractants that were adopted in monitoring this pest. His work on Gymnandrosoma aurantiana, a pest of citrus in Brazil, led to a monitoring program that is credited with saving citrus farmers in São Paulo $137 million (in U.S. dollars) during the first 12 years of this century.”

Oehlschlger wrote that Leal’s work on NOW is crucial to managing it; it is “the major insect pest in the $8.9 billion dollar California nut production industry.”

Professor John Pickett of Cariff University, a past president of ISCE, described Leal as “a truly outstanding scientist working in the field of chemical ecology and specifically in the practical development of tools from this subject for human endeavor and improvement of our wellbeing.”

Professor Paulo H. G. Zarbin of the Department of Chemistry, Federal University of Paraná, Brazil, collaborator and former ISCE president, commented on “Walter’s exceptional track record of scientific contributions, technological innovation, and the tangible benefits his work has delivered…His career continues to inspire and set a high standard for applied chemical ecology.”

“I have had the privilege of collaborating with Walter since the early stages of my doctoral studies, during which I was consistently inspired by his dedication, creativity, and strategic vision,” Zarbin wrote. “Walter’s work exemplifies excellence, combining innovation with a profound awareness of the societal impact of science.”

Black-and-white passport photo of young man in suit and tie, embossed seal — A 1976 passport image of Walter Leal

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.

Also at the ISCE meeting, Leal zeroed in on science and reporting by interviewing various colleagues and posted on LinkedIn via YouTube.