- Cool-Season Grass
- Cool-Season Vegetable Crops
- Dry Beans
- Field Corn
- Invasive Pests
Statement of Problem: Cotton is an important crop in CA, although acreage has declined in recent years. In addition, the species of cotton grown has shifted over the last 10 years from exclusively Acala to now ~45% Pima cotton. These changes have largely been because of economics including pest control costs. Yield losses from insects and mites were estimated at 0.4% in 1991 and peaked at 11.3% in mid-late 1990’s. Concomitant with this, costs for pest control were $10/A in 1991 and peaked at $100-125/A. The primary culprit was the cotton aphid (Aphis gossypii), but spider mites, lygus bugs, sweet potato whitefly strain B, and beet armyworm were also problematic. At my laboratory at the Shafter Research station, I have a fulltime Staff Research Associate, and several graduate students have done their research centered at this location over the last several years. Several undergraduate assistants work during the summer. We work closely with the other Univ. of California personnel, including the Cotton Agronomist, Cotton Farm Advisors, and UC-IPM Advisor.
Examples of Work during Recent Years
- The role of insecticides, particularly reduced-risk materials, in management of key arthropod pests (spider mites, cotton aphids, lygus bugs, and whiteflies) is being investigated.
- The role of production practices such as nitrogen fertilization, planting date, use of broad-spectrum insecticides in pest population development.
- Damage potential of sweet potato whitefly in the SJV was studied.
- Studies on the seasonal life history of cotton aphid were done.
- Treatment thresholds, plant biomass and physiological responses to mid-season cotton aphid infestations in SJV cotton have been evaluated.
- The utility of releases of predatory mites for the management of spider mites in cotton.
- Applicability of remote sensing for detecting developing spider mite, lygus bug, and cotton aphid infestations.
- Factors influencing sticky cotton occurrence and severity.
Cotton Aphid Overwintering Biology
Cotton aphid, Aphis gossypii, is a highly damaging pest to several crops in California, e.g., citrus, cucurbit, cotton, celery, eggplant, nursery plants, etc. This pest reduces crop yields, contaminates commodities with excreted honeydew, transmits virus diseases, and contributes to increased crop protection costs. In recent years, citrus tristeza virus has been a severe problem. Pomegranates are the only identified overwintering/primary host for cotton aphid in California and the virus increase has occurred concomitant with an increase in pomegranate acreage in this region. We have been studying several key characteristics of the cotton aphid overwintering biology in hopes that this may offer a unique opportunity to favorably impact management of this key pest.