California Olive Research Articles

Weather‐mediated regulation of olive scale by two parasitoids

Summary The effects of temperature and interspecific competition among two parasitoids (Aphytis maculicornis (=paramaculicornis) (Masi)–Coccophagoides utilis Doutt) of the olive scale (Parlatoria oleae (Colvée)) were examined, and the reason for the successful biological control of olive scale explained. An age‐structure distributed maturation time model of this system was developed that simplifies many of the details of prior physiologically based models. Temperature‐dependent physiological indices were used to scale fecundity and survivorship rates from their maximum values. The distributed maturation time population dynamics model captured the variance in temperature‐related development times required to simulate the dynamics of the system. A type III ratio‐dependent functional response was used to estimate parasitism rate on olive scale and also served to stabilize our single patch model. The model confirms the Huffaker & Kennett (1966) conclusions concerning the role of weather and the relative contribution of the two parasitoids in the regulation of olive scale in California olive.

Plant parasitic nematodes associated with olive1

Over 70 species, belonging to 33 genera, of plant parasitic nematodes have been reported in association with olive. Several species of Helicotylenchus have been observed to cause root necrosis and considered capable of affecting olive tree growth. Three species of Meloidogyne (M. incognita, M. lusitanica and M. javanica) were responsible for heavy galling and growth retardation in inoculation trials and natural infestation. Pratylenchus vulnus has been demonstrated in inoculation trials as a potential pathogen of olive. Xiphinema species commonly occur around olive roots and X. elongatum has been shown to affect olive plant growth. Several sedentary plant nematodes attack olive. Tylenchulus semipenetrans infects olive in California (US) and Italy. Trophotylenchulus saltensis was described from olive roots in Jordan and a cyst nematode, Heterodera mediterranea, was shown to feed and multiply on olive roots. The cortical feeding cells of roots fed upon by Gracilacus peratica showed thickened and lignified wall near the penetration points of the stylet and those exposed to Ogma rhombosquamatum also presented hypertrophic nuclei and nucleoli. Rotylenchulus macrodoratus induces the formation of an enlarged mononucleate stelar or cortical ‘nurse cell’ with dense cytoplasm and hypertrophic nucleolus.

Some Rootstock and Interstock Influences in the Olive (Olea europaea L.) cv. Sevillano1,2

Abstract An olive rootstock planting was established in Tulare County, California in 1954 using 10 different rootstocks with ‘Sevillano’ as the scion variety. Verticillium wilt, a major problem in California olive production, became strongly established in this planting, affecting trees on the different rootstocks to a markedly different degree. All trees on 2 of the rootstocks, Olea ferruginea Royle and Forestiera neo-mexicana Gray were killed. No trees on a clonal rootstock, Olea europaea, ‘Oblonga’ were affected, while trees on the 7 other rootstocks showed intermediate survival percentages. Over a 15-year period, tree size and yields were influenced by the rootstock. ‘Sevillano’ trees, on their own roots, were the smallest as measured by trunk cross section area. There was no pronounced effect of rootstock on fruit size. In another olive planting in Tulare County, California, the effect of various interstocks, inserted during a top-working operation, on the behavior of the scion cultivar was determined. No Verticillium wilt was apparent in any of the trees in this experiment. Each of 3 genetically dwarfed clonal stocks caused a significant dwarfing influence on the scion cultivar and a reduction in yields, in comparison with the scion cultivar itself used as an interstock. No influence on fruit size occurred. Similar results were noted with Olea chrysophylla Lamk. as an interstock but with severe constriction of the interstock tissue.

Time of Floral Differentiation of the Olive in California

1. The beginning of floral differentiation in the olive in California was found in 1946 and 1947 to occur usually during the month of March, about 8 weeks before full bloom. 2. Little, if any, difference was noted in time of floral differentiation among the three varieties studied or among the five localities from which bud samples were collected. 3. No change occurred in the microscopic appearance of the bud from the time it was formed in June until the floral parts appeared the following March.

Extracted California olive oil

SummaryExtracted olive oil is not used exclusively for soapmaking but in fact is used to the utmost extent in edible oils. General processing procedures are outlined for the production of edible olive oil from high acid extracted olive oil.

California olive oil studies

California olive oil studies

New possibilities in California olive oil

I. There is a field for increasing the return on oil olives through feeding the pomace to livestock, and through increasing the oil yield by the use of more powerful presses, or exhausting the oil content of the pomace by solvent extraction.

The chemical composition of california olive oil

The chemical composition of california olive oil

The chemical composition of California olive oil

The chemical composition of California olive oil