Lindcove Research and Extension Center
University of California
Lindcove Research and Extension Center

Olive

124 - Use of PGRs to Increase Bud Break and Growth of Vegetative Shoots

Principal Investigators: Dr. Carol Lovatt, Botany and Plant Sciences, University of California Riverside.  Dr. Elizabeth Fichtner, Farm Advisor University of California Cooperative Extension, Tulare County.

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Alternate bearing (AB), production of a high yield "on-crop" (ON trees) followed by a low yield “off-crop” (OFF trees), is a significant economic problem for table olive growers. In ON years, trees produce a large number of small fruit with reduced commercial value. In OFF years, trees produce large fruit but too few to provide a good income. AB is typically initiated by a climatic event that reduces yield, resulting in an OFF crop that is followed by an ON crop. Once initiated, AB becomes entrained through the effect of crop load on endogenous tree factors that ultimately impact floral intensity, such that the ON-crop reduces bloom the following spring, whereas the OFF-crop results in an intense return bloom. “Olives, for all practical purposes, are borne on one-year-old shoots (i.e. grown the previous season). In the year of the heavy crop, shoot growth that will bear the inflorescences for the subsequent crop is physically depressed - without fruitful shoots, no crop will occur the following year”. We are testing the hypothesis that fruit disrupt the hormone homeostasis of the buds and thereby inhibit shoot extension growth in summer and bud break in spring. Concurrently, we are testing the efficacy of plant growth regulator (PGR) treatments to overcome the inhibition of bud break in summer and spring, respectively, to increase the floral intensity of the bloom following the ON-crop.

075 - IR-4 Pesticide Residues

Principal Investigator: Dr. Jeff Dahlberg, Kearney Agricultural Center

The Inter-regional Research Project #4, or IR-4, was created by the U.S Department of Agriculture (USDA) in 1963 to aid growers of high-value specialty crops in obtaining pesticide registrations that would otherwise be unavailable. For a pesticide to be labeled for use, a tolerance, or the legal allowable limit of pesticide residues, must be established on that crop. The cost to register pesticides for specialty crops far exceeds the purchases made by the growers and packers. In response, the publicly funded national IR-4 Project was established to facilitate pest management solutions for specialty crop growers. Citrus, avocados and olives are specialty crops. By facilitating the registration of new pesticide uses in these crops, the IR-4 project helps the growers and packers use safer pesticides, use existing pesticides in more ways, have access to enough pesticides to help reduce the development of pesticide resistance in the pest populations, respond to invasive or new pests, and/or increase export market potential. This is done by having trials throughout the United States that mimic commercial practices, apply new pesticides to commodities, and send samples for analysis of residues. The field and lab data package is sent to EPA so that tolerances can be set and the new (often reduced-risk) pesticides or new uses of existing pesticides can be registered. The permanent plantings at Lindcove REC are used to conduct IR-4 trials on citrus, avocado and olive crops.

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