Croonian Prize Lecture
Professor John Pickett FRS, Rothamsted Research
Organisms of all kinds use signals comprising minute amounts of natural chemicals. Whether these are pheromones involved in developmental regulation and sexual interactions, or other types of chemical signals (semiochemicals) that relate to interspecific interactions including germination cues or food and host attractants, such semiochemicals potentially provide new chemical tools for managing pest and beneficial organisms.
The exploitation of semiochemicals is demonstrated with dramatic success in the management of pests and parasitic weeds in resource-poor East African cereal farming. However, the underpinning science extends to intensive agriculture and also to animal husbandry and human health. There are common features of semiochemically mediated communication that determine both positive cues, such as those involved in seed or spore germination and reproductive site, food or host location, but also inhibitory processes and the avoidance of inappropriate members of a potential host range. Not only can these types of semiochemicals be used to "push" and "pull" the behaviour or development of pest and beneficial organisms, but they may, by relating to biotic stress, also be used to "switch on" defence at earlier stages prior to attack by a pest, pathogen or parasitic weed. These same stress-related semiochemicals are available for capturing the benefits of organisms antagonistic to pests.
To understand and exploit semiochemicals, a truly multidisciplinary approach comprising highly sensitive chemical, spectroscopic, electrophysiological and molecular biological approaches is exemplified.