Search Results

You are looking at 1 - 10 of 14 items for

  • Author or Editor: L. Ferguson x
Clear All Modify Search

The effects of four mechanical pruning treatments [hedging, topping, hedging/topping, and hand-pruning (control)] on nut yield, nut quality, alternate bearing, and growth of 14-year-old female `Kerman' pistachio trees on Pistacia atlantica L. rootstocks were assessed. A single pruning was done before an “off,” or low-crop, year followed by retopping of those treatments incorporating topping the first year. Over 7 years, yields of hedged/topped and topped trees were equal to those of control trees, while hedged trees produced significantly less. The incidence of nonsplit shells and blank nuts were not affected by pruning. Nuts weighed more all years for hedged/topped and topped trees than for the others. Alternate-bearing indices within 7 years were lower for pruning treatments incorporating topping. Topping mitigated the fluctuating annual vegetative growth pattern and resulted in 27% of the shoots retaining buds through three successive alternate-bearing cycles after the year of treatment. Hedged/topped and topped trees had significantly less alternation in annual girth growth than control or hedged trees. These results demonstrated that two successive seasons of mechanical topping, started before the off year, produced changes in shoot growth, trunk growth, and bud retention that mitigated alternate bearing through three biennial cycles, without decreasing yield. Thus, severe annual hand-pruning could be used to prevent or minimize alternate bearing of pistachios.

Free access

Management problems and information needs of Florida's approximately 12,000 citrus growers on 791,290 acres were identified by a statewide citrus management survey. During the summer of 1992, citrus county agents' mailing lists were compiled to create a master list of 2,964 addresses, from which a sample of 833 growers was selected by a stratified proportional sampling procedure. Three hundred ninety-eight useable questionnaires were returned from commercial citrus grove owners and managers in 23 citrus producing counties, representing 307,022 acres, 39% of the current acreage. Survey data on general management, young tree care, pest management, water management and cold protection was further analyzed by whether respondents' groves were bedded or unbedded. Information from this citrus survey and previous ones has been used to develop and evaluate comprehensive statewide citrus extension programs.

Free access

Several experimental procedures were used to evaluate the influence of solar radiation on insect infestations in Calimyma and Adriatic variety figs (Ficus carica L.). Direct sunlight eliminated infesting insects and prevented further infestation of ripe figs drying on the ground for at least 10 days. Placement in the shade resulted in 12% insect infestation in figs within 3 days. Figs that fell naturally into sunlit areas contained almost no insects, whereas 31% of figs that fell into dense shade were infested. While ripening figs were still attached to trees, the level of insect infestation was 50% higher on the shady north side than the sunny south south side. The insect pests most frequently encountered in these experiments were nitidulid beetles and their larvae. Disease incidence was not affected by degree of exposure. We propose that cultural techniques to maximize exposure of ripening and drying figs to solar radiation could be developed as important pest management tools.

Free access

Abstract

Several experimental procedures were used to evaluate the influence of solar radiation on insect infestations in Calimyrna and Adriatic variety figs (Ficus carica L.). Direct sunlight eliminated infesting insects and prevented further infestation of ripe figs drying on the ground for at least 10 days. Placement in the shade resulted in 12% insect infestation in figs within 3 days. Figs that fell naturally into sunlighted areas contained almost no insects, whereas 31% of figs that fell into dense shade were infested. While ripening figs were still attached to trees, the level of insect infestation was 50% higher on the shady north side than the sunny south side. The insect pests most frequently encountered in these experiments were nitidulid beetles and their larvae. Disease incidence was not affected by degree of exposure. We propose that cultural techniques to maximize exposure of ripening and drying figs to solar radiation could be developed as important pest management tools.

Open Access

Six comprehensive surveys of the Florida citrus industry (345,645 ha), published from 1989 to 1993 as extension bulletins, provide information essential for long-range research and extension program planning and evaluation. These surveys documented changes in production practices, regional priorities for extension programming, marketing trends, and grower ranking of information sources. While formal, comprehensive surveys may be a valuable tool in long-range extension programming for large horticultural industries, more rapid, creative survey methods and educational programs may be needed for more timely programs and for specialized industry groups.

Full access

Two experiments were conducted with containerized `Hamlin' orange trees (Citrus sinensis [L.] Osb.) on `Swingle' citrumelo (C. paradisi Macf. × Poncirus trifoliata [L.] Raf.) rootstock to study the effects of N rate on growth of plants in the nursery. Treatments consisted of the following N rates: 12, 50, 100 and 200 mg·liter-1 applied once a week through drip irrigation. In Expt. 1, fertilization at the 200 mg·liter-1 rate resulted in greater scion growth, trunk diameter and total leaf dry weight as compared to the other rates. In Expt. 2, application of 100 and 200 mg·liter-1 rates resulted in greater scion growth and trunk diameter as compared to lower rates, but no differences were seen between the two highest rates. Trees receiving the 12 and 50 mg·liter-1 rates were stunted and leaves were chlorotic. Therefore, the optimum N rate for trees on `Swingle' citrumelo rootstock is between 100 and 200 mg·liter-1, although the 200 mg·liter-1 rate may not be economically justified. Moreover, the N rate for nursery plants growing on `Swingle' citrumelo rootstock in commercial medium may be higher than for other rootstocks, where rates less than 50 mg·liter-1 produce optimum growth.

Free access

Pistachio (Pistacia vera L.) is known to strongly exhibit alternate bearing. Over 19,500 individual shoots were measured on eight alternate bearing `Kerman' pistachio trees on P. atlantica Desf. rootstock. Average length of “on” year (5.4 cm) and “off” year new shoots (5.6 cm) were not significantly different. New shoot length distribution was skewed toward the shorter length categories, with a mode of 2 and 4 cm in “on” and “off” trees respectively. These results contrast with previous studies which have shown that “on” year new shoots of pistachio are much longer than “off” year new shoots. There were about twice as many “on” year new shoots in the 18 to 30 cm class as compared to “off” new shoots, and fruiting wood length was associated positively with fruit number. However, ≈80% of tree yield occurred on fruiting wood that was <10 cm long, with shoots longer than 15 cm contributing <5% to yield. We suggest that results from earlier studies regarding the bud abscission process in very long pistachio shoots should be confirmed on shorter shoots, which contribute significantly to yield. Shoots >30 cm in length may be important in establishing vegetative buds in a position above the main tree crown for canopy expansion during the following “off” year.

Free access

Abstract

Infra-red light induced stem elongation of several species of plants. Tomato plants also had reduced fruit yield. Geraniums had wider leaves and longer internodes and flower stalks, but the no. of flower stalks was unaffected by infra-red treatment. These effects should be taken into consideration if infra-red heating is to be used in greenhouse operations.

Open Access

Developing mechanical harvesting is the most effective, and most difficult, factor in improving horticultural crop profitability. It requires simultaneous incremental changes by multiple entities; engineers, horticulturists, food scientists, economists, local extension personnel, the commercial harvester industry, growers, and displaced laborers and their management. There is a narrow annual testing window. The initial research by engineers and horticulturists focuses on developing effective removal technologies and can be applied or basic. When funding is local, the research is generally applied and is usually an adaptation of existing technology. With national funding, the research is basic or investigates novel technologies. Both are conducted first on model systems or individual plants. Properly executed, both types can be published, but publication is difficult if engineering parameters are changed during the trials. Evaluation of developed removal technologies requires cross-disciplinary teams to evaluate the effects on the final marketable product quality and long-term plant health. Publications can be produced on testing technology or effects on marketable product quality or plant health. An industry education program with field days, industry publications and websites, and annual presentations should frequently report progress. Finally, a prototype should be demonstrated to show the economic feasibility of a mobile platform with catching technology. The research team then expands to include the harvester industry and grower cooperators. Orchard adaptations to increase harvester efficiency are incorporated at this point. Usually by this time all research is applied and the funding local. If results demonstrate economic feasibility, the technology should now segue to the commercial harvester industry as university laboratories mostly lack the capacity to generate truly commercial harvesters. Publications could be delayed to avoid premature disclosure to make patents achievable and to facilitate cooperation between university researchers and commercial fabricators.

Full access