Biological and Agricultural Engineering

Ecological Systems

Given that California is headed toward a population of over 50 million, farms take on a special importance as open space and relief from urban sprawl. Farms support wildlife. Sacramento Valley rice fields, with a quarter of a billion pounds of waste grain left after harvest, can sustain more waterfowl than the region’s four National Wildlife Refuges. Great numbers of songbirds subsist on California’s orchard crops and insects that flourish in crop fields. Maintenance of the state’s natural resources and a clean environment, while farming, are critical to the wildlife indigenous to California.

Research in ecological systems engineering focuses on the design, development, and management of ecological systems. For example, tidal wetland and watershed restoration research is underway in the San Pablo Bay area and the north coast. The value of reestablishing native oak watersheds in the Napa, Sonoma, and Mendocino Valleys, in association with vineyard and urban development, is being studied. Managing pests in agricultural systems and bioremediation/utilization of wastes are also two major areas for our department. The overall goal in most of our projects is to maintain a pollution free environment, one which maintains natural biological diversity. This section focuses primarily on pest management. Residue management is reviewed further in the next two sections. Timely and appropriate application of pesticides and biological agents can result in a higher quality and quantity of agricultural crops. The application system is a key link in the overall safety, effectiveness, and economy of most treatments. The goals in all our plant protection research are to minimize chemical and biological material use through efficient application and to avoid environmental pollution. The aerodynamic transport of spray droplets from atomization devices to the interiors of plant foliar canopies and electronic systems for spray target sensing and application control are being studied. All projects assess application efficiency and off-target drift. Systems to prevent spray drift in sensitive areas and allow control of spray applications through satellite navigation have been developed and are being refined.

Release of predators and parasites for control of insects and arthropods is currently practiced in commercial agricultural production. Unlike conventional pesticide application, release of such control agents is most commonly a manual process. For example, predacious mites are often used for control of two-spotted spider mites in strawberries. The distribution technique is tedious and results in non- uniform populations of mites. One project developed a simple, mechanical, tractor-mounted mite distributor which is now being used commercially. Further projects developed systems to apply insect eggs to vineyards; these systems are being tested in commercial vineyards.

Odor can be used to attract or confuse insects. An insect olfactometer has been constructed for studying insect response to different scents. Another project.involves use of sex pheromones for disruption of insect mating. We are presently developing a biodegradable pheromone carrier which can be directly applied to the tree with a targeted sprayer, providing more efficient application and better control through more diffuse release.



Pilot-scale reactors have been constructed on campus to provide design criteria for wetland systems treating winery effluent. Goals of this research are aimed toward improving the overall biological process.



Research is underway in culti-vating high valued mushrooms and nutritional livestock feed from the growth media residue. This student is shown inoculating rice straw samples with edible fungus spawn.


The use of global positioning system (GPS) equipment provides an efficient means of mapping ecosystems. This backpack GPS unit receives signals from satellites that inform the user of their exact location in the field.



Beneficial insects can be released to control harmful insects. This can reduce the need for pesticides. Here a student monitors the condition of beneficial insect eggs that have been applied to a grape canopy.



Specialized equipment is being developed to handle and apply beneficial insect eggs. This student is preparing a test machine to spray insect eggs onto a test vineyard.



Synthetic sex pheromones can be used as part of an integrated pest management strategy to control insect pests by disrupting their reproduction behaviors. Research has focused on the development of a sprayable paraffin emulsion as a carrier for the pheromones. Pictured is the sprayer designed for this purpose.



Application of beneficial insects can reduce the need for chemical sprays. Here a student is calibrating an application system to apply insect eggs in a commercial vineyard along the Central Coast of California.



After lab testing, prototype machines are taken to commercial fields for real-world testing. This student uses a newly designed machine to apply insect eggs to a California wine grape vineyard.