The underlying theme involves understanding the role of weeds in the agroecosystem, with special emphasis on their population biology. I have concentrated on barnyardgrass as it is the most important summer annual weed in all California warm-season crops. We are having to rethink population dynamics based on much higher numbers than previously considered. Seed production by weeds in general is poorly understood. This will be used to investigate seed production in common weeds in California agroecosystems.
Weeds are, after all, green plants that serve as food sources for many organisms.
We are planning to start to determine the ability of weeds to support populations of the sugarbeet cyst nematode. Allied to this area is that of biological weed control. I have done extensive work on the impacts of two leaf mining insects on growth and development of common purslane. We have been unable, however, to show any benefit, in the form of reduced competition, when the weed competes with sugarbeets in the field. The only alternative is hand weeding and it seems unlikely that any large percentage of the California population will return to this vocation.