Although scientists have made headway in developing biological methods of controlling agricultural pests, the equipment used to apply traditional chemical pesticides may not be suitable for the new "biorational agents," according to William E. Steinke, a Cooperative Extension agricultural engineer at UC Davis. Steinke has examined existing practices and future needs for handling, metering, dispersing and collecting biorational agents such as bacteria, viruses, fungi, pheromones, predators and parasites.