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Vincent Ianaro and Robert J. McNeil

The Fuerte avocado cultivar is known to be an alternate and inconsistent producer of avocados in cool coastal areas and hot interior areas of California because of its sensitivity to such extremes of climate during its bloom and fruit setting periods. This study attempted to increase fruit set and yield of this cultivar in a cool central coast area by applying a three-eighths inch wide girdle to one large limb, equivalent to one-third of the tree, on each of five 43-year-old trees. A double bladed girdling knife was used to remove the bark all around each limb. Another equal sized limb on each tree was used as the control. Girdling was completed on December 15. Girdled limbs had means of 42.6 more pounds which was 186.8% more fruit yield as compared to control limbs. Girdled limbs also had means of 89 more fruit which was 222.5% more fruit by count than control limbs. Fruit on girdled limbs was smaller in size (8.1 oz. average) than that on control limbs (9.1 oz. average) but was still of an acceptable size to bring good prices.

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Robert J. McNeil* and Colleen M. Dettling

A 4-year `Satsuma' mandarin cultivar trial was conducted on the California Central Coast in San Luis Obispo. Cultivars compared were Owari, Dobashi Beni, and Okitsu Wase, all on Carizzo citrange rootstock. Trees were from 3 to 6 years of age and in their first 4 years of production during the four seasons that data was taken. Data taken each year was fruit maturity, color, size, and yield. Tree size was measured in the fourth year. `Okitsu Wase' fruit were harvestable 2 to 4 weeks earlier than `Owari' and `Dobashi Beni' considering meeting both minimum soluble solids to acid ratio (6.5/1) and minimum color (75%). `Okitsu Wase' was more consistent as to time of maturity. Maturity time of all cultivars varied each season based on weather. `Okitsu Wase' first minimum internal maturity varied from 15 Oct. to 1 Nov. Minimum color varied from 1 Nov. to 1 Dec. Dobashi Beni first internal maturity varied from 15 Oct. to 31 Dec. Minimum color varied from 15 Nov. to 31 Dec. Owari first minimum internal maturity varied from 15 Nov. to 31 Dec. Minimum color varied from 15 Nov. to 31 Dec. `Owari' had the highest total yield for the 4 years, followed by `Dobashi Beni'. `Okitsu Wase' had a significantly lower total yield than the other two cultivars for the 4 years. `Okitsu Wase' had higher percentages of smaller fruit and lower percentages of larger fruit than the other two cultivars in the first and fourth crop year, but had comparable percentages of larger fruit in the second and third year. The `Okitsu Wase' was a smaller tree than both the `Owari' and `Dobashi Beni' in height, width, and canopy volume.

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Daniel E. Ray* and Robert J. McNeil

The objectives of the study were to measure the effectiveness of Ditera WDG, a biological nematicide derived from the fermentation of a nematode-parasitic isolate of the Myrothecium species, in controlling citrus nematode numbers and the effects on tree growth, fruit yield, and fruit size as applied through minisprinkler irrigation. Nematode-infested trees utilized for the study included three different blocks of sweet oranges: 1) 20-year-old `Valencia' orange trees on Troyer citrange rootstock; 2) 15-year-old Washington navel orange trees on Troyer citrange rootstock; and 3) 8-year-old Washington navel orange trees on three citrange rootstocks (Troyer, Carizzo, and C-35). Three treatments were utilized within each orchard block: 1) 28.01 kg of active ingredient per hectare (25 lb per acre); 2) 56.02 kg of active ingredient per hectare (50 lb per acre); and 3) an untreated control. Treatments 1 and 2 were split into early spring and early fall applications for three seasons. Chemical was injected through minisprinkler irrigation in a 3.41 m (11.2 ft.) diameter under each tree. There was a positive trend toward reduction of nematode numbers for the high rate of Ditera in all three treatment blocks and for the low rate in one block. Effects on tree growth, fruit yield, and fruit size will also be presented.

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Anastacio P. Naranjo and Robert J. McNeil

The purpose of this experiment was to measure the difference in temperatures influenced by skirted and unskirted cirrus trees under cold temperatures. Sixty citrus trees (oranges and lemons) planted on a hillside were skirted at 18 inches above ground level for this experiment. The experiment was conducted over 96 days, in which daily minimum temperature readings were taken. In addition to the thermometers, four thermographs were used to record constant temperate and duration of frosty nights.

In 79 of the 96 days of the experiment, the skirted treatment showed an increase in the temperature compared with the unskirted treatment at an average increase of 0.25°F. Statistical differences between treatments ranging from 0.5°F to 0.7°F were found for three different days at temperatures in the 40's. No statistical differences between treatments were found at temperatures in the 30's. The thermograph readings showed no differences in the duration of cold temperatures between skirted and unskirted treatments.

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Anastacio Perez Naranjo and Robert J. McNeil

The experiment compared productivity and vegetative growth of the Hass avocado on three avocado root rot resistant rootstocks and one susceptible rootstock. Hass trees on Duke 7 reported the largest number of fruit per tree and on G 755c the smallest five years after planting. Trees on Topa Topa and Duke 7 reported the highest average production four years after planting. Trees on G 755c were significantly lower in the amount of leaf N. Trees on Toro Canyon and G 755c showed significantly lower amounts of Na. Trees on Duke 7 showed a significantly higher level of Mn. Trees on G 755c were significantly smaller two years after planting. Trees on Topa Topa and Duke 7 showed a significantly larger canopy diameter than those on G 755c four years after planting. Trees on G 755c showed the smallest mean shoot growth four years after planting. Trees on G 755c had significantly larger trunk circumferences three and four years after planting. No statistical differences were found among rootstocks as to freeze damage to the Hass scions.

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Robert J. McNeil, David O. Medders, and Ramiro Guzman

Six freezing protectant products were sprayed at label rates on 1-year-old `Hass' avocado trees. Control trees were sprayed with water. Treatments were applied three times at monthly intervals, 20 Dec., 20 Jan., and 20 Feb. The products tested were Copper Count-N, Champ, Frostguard, Frost Shield, Anti Stress 550, and Insulate. Two separate orchard areas were treated, one with additional freezing protection by a wind machine and the other with no wind machine. Freezing temperatures and subsequent leaf damage occurred on 4 Jan., which was 2 weeks after the first treatment. The wind machine protected area experienced 2 h at or below 30 °F, with a minimum temperature of 29 °F, while the area without a wind machine experienced 5.5 h at or below 30 °F with a minimum temperature of 27.9 °F. One hundred mature leaves per tree were rated as to any freezing damage, slight damage (1% to 33%), moderate damage (33% to 66%), or severe damage (66% to 100%). All six freezing protectant products consistently reduced the percentage of leaves with freezing damage below that of the water-treated control trees, except in one instance, for all four categories of leaf freezing damage evaluated in both orchard areas—that with and that without a wind machine. Damage was reduced by approximately half for some of the treatments as compared to control trees. Data for some or all freezing protectant products was statistically different (less) than the control in two freezing damage categories (slight and moderate) in the area without a wind machine, however, data was not statistically different between freezing protectant products.

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Hannah M. Mathers, Alejandra A. Acuña, Donna R. Long, Bridget K. Behe, Alan W. Hodges, John J. Haydu, Ursula K. Schuch, Susan S. Barton, Jennifer H. Dennis, Brian K. Maynard, Charles R. Hall, Robert McNeil, and Thomas Archer

The U.S. nursery and landscape industry generates 1.9 million jobs and had an annual payroll of greater than $3 billion in 2002, yet little is known about nursery and landscape workers. This lack of information is even more pressing considering that labor generally accounts for greater than 40% of production costs and 31% of gross sales. Labor shortages, immigration reform, and legal status of employees are widely reported as the industry's most critical issues. We hypothesized that relevant data regarding the nursery industry workforce may raise an appreciation of the industry's diversity, increase political power and public awareness, and help stakeholders evaluate policy decisions and plan corrective strategies in a more informed manner. A total of 4466 self-administered questionnaires were sent in 2006, attempting to reach 30 nurseries in each of nine states with 1561 returned (35% response rate). Hispanics constituted 70% of the average nursery workforce, including general laborers (76%), crew leaders (61%), and sales/managers (others) (21%). Across firms, labor retention was less than 51% after 5 years and only 22% of employees understood English, raising questions regarding availability and access to training. Sixty percent of nursery employees had not received work-related training, although 81% of men and 72% of women were interested, and an association between training and employee retention existed. The highest rated training topic of interest was English/Spanish (respective of Spanish/English primary language respondents). There was a positive correlation between developing fluency and worker turnover, making the laborer attrition rate even more unfavorable for employers who not only lost employees with acquired experience, but also with acquired English skills.