9420013 Schultz Because they lack mobility, plants have had to develop dynamic responses to changing environmental conditions and stresses such as insects and disease. Most studies have examined responses to individual enemy species in isolation. However, plants are attacked by communities of insects and diseases. Many studies reveal considerable overlap in the key biochemical mechanisms of plant responses to various enemies. We hypothesize that overlapping plant responses frequently yield overlapping effects on multiple enemies, determining which pests will actually infest a plant at any point in space or time. We will test this hypothesis by examining the responses of several cucumber varieties to insect pests and diseases. We focus on cucumbers because they have well-studied resistance mechanisms, insect pests, and pathogens. First, we will characterize overlap in biochemical responses of individual plants to infection by a virus, bacterium, and fungus, and infestation with one of four cucumber-feeding insects. We will then "challenge" these responding plants with each of the other pests and determine which biochemical mechanisms provide "cross resistance" to more than one. Finally, the ecological importance of "crossed" or generalized resistance factors will be assessed by exposing young field-grown plants to the same infection/infestation treatments as above, but then allowing natural development of the pest community throughout the growing season, assessing both pest community accumulation and plant yield. This research will put interactions among plants, insects, and plant diseases into a realistic community context. The broad goal is developing a predictive plant-pest science that will provide improved plant breeding, genetic engineering, and cultivation practices for improved pest resistance and reduced crop losses, as well as understanding the development of plant-pest interactions.
