Spider mites are a chronic and damaging pest of nurserystock and landscape in California.
Production horticulture is increasingly using drip irrigation to conserve water and reduce runoff. However, growers sometimes use overhead irrigation because they have observed that mites are not as much a problem when the plants are irrigated in this manner. In this experiment, containerized roses will be established under early morning and mid-day drip and overhead irrigation treatments to determine if spider mite populations are influenced by environmental conditions of temperature and humidity, and to determine if favorable environmental conditions can be influenced by irrigation method and frequency. Additional experiments will be conducted to determine if irrigation practice can enhance the effects of predaceous mites for control of two-spotted spider mites. Establish effective natural enemies that will provide consistent, long-term biological control of the giant whitefly.