An herbicide applicator that sprays only when it "sees" a weed. An orchard device that "puffs" clouds of sex-scented hormones to drive insect pests crazy. A bionic arm that helps farmworkers become more productive and less injury prone. These are examples of the fascinating new technology to be showcased for California agriculture May 21 during AgTech '97 at UC Davis. "AgTech will give the state's fruit and nut growers a rare opportunity to see field demonstrations of the technology they will be using in the next century," said Louise Ferguson, a UC Cooperative Extension pomologist and conference chair. "This innovative technology has reached the applied stage but is not yet in general commercial practice." More than 75 demonstrations are planned in a wide range of production topics -- biotechnology, composting and mulches, farm management, GPS and mapping, integrated pest management, irrigation, new variety breeding, postharvest technologies, precision spray equipment, safety and ergonomics, weed control techniques and World Wide Web technology.