`Fontana', `Iridon', `Pink Lady', `Splendor', `White Diamond', and `White View Time' chrysanthemum (Dendranthema × grandiflorum Ramat.) were grown for 10 weeks with N rates of 80, 160, or 240 mg·L-1 constant liquid fertilization and irrigated at sufficient (high) or deficient (low) amount. Cultivars differed in growth habit, and treatments significantly affected all variables measured. Plants fertilized with 80 mg·L-1 had lower leaf and stem dry mass, less leaf area, and were deficient in leaf N compared with plants fertilized with twice the amount of N. The highest stem dry mass was produced with 160 mg·L-1. Leaf and stem dry mass were reduced 25% for plants receiving low irrigation compared to those receiving high irrigation. In general, leaf area increased when fertilizer was raised from 80 to 160 mg·L-1 but differed by cultivar and irrigation regime when fertilizer was increased to 240 mg·L-1. Three weeks after the experiment started, electrical conductivity (EC) of runoff collected weekly from `White Diamond' plants fertilized with 240 mg·L-1 exceeded the average EC of the irrigation solution. The 240 mg·L-1 treatment also resulted in excessive EC in the growing substrate at the end of the experiment and reduced stem dry mass by 11% compared with the 160 mg·L-1 fertilizer regime. Substrate EC differed between cultivars in response to fertilizer and irrigation. Significantly more adult western flower thrips [Frankliniella occidentalis (Pergrande)], 55% and 52%, were found on the foliage of `Pink Lady' and `Fontana', respectively, than on `Iridon'. `Pink Lady' and `Fontana' had more immature thrips at the end of the experiment than `Iridon' and `White View Time'. Fewer adults and immatures were found on plants fertilized with 80 mg·L-1 than 240 mg·L-1. Fewer adults were detected in plants under high versus low irrigation, while irrigation had no effect on the number of immatures. The simultaneous use of plant varietal resistance and plant cultural growing techniques has the potential to lower thrips populations on chrysanthemum.
Ursula K. Schuch, Richard A. Redak, and James A. Bethke
Ursula K. Schuch, Leslie H. Fuchigami, and Mike A. Nagao
The effects of water stress and GA, on breaking dormancy of flower buds of coffee (Coffea arabica L.) were investigated. In the first experiment, water was withheld until the trees reached leaf water potentials (WP) of -1.20, - 1.75, -2.65, or -3.50 MPa. Water potential, ethylene production, and ion leakage of flower buds and leaf disks were examined from release from water stress until anthesis. Trees that had experienced leaf WP of less than - 2.65 MPa, and flower bud WP of about - 4.0 MPa flowered within 9 days after irrigation. In flower buds where dormancy had been broken with water stress, ethylene production was low compared to dormant buds and flowers at anthesis. In the second experiment, O, 50, 100, or 200 mg GA3/liter was painted on branches of nonstressed trees. In experiment three, water was withheld until plants reached leaf WP of -0.6, -1.3, - 2.1, or - 3.0 MPa, then two branches per tree were painted with O, 50, and 100 mg GA3/liter. Gibberellic acid partially compensated for insufficient water stress to initiate flower opening. Ethylene evolution of flower buds was affected by water stress but not by GA3 treatment. Severe water stress treatments and GA, treatment (200 mg·liter-1) increased ethylene evolution of leaf disks. Ion leakage of flower buds and leaf disks was increased by severe water stress. Ion leakage of flower buds was highest at anthesis. After water stress, dormant and nondormant flower buds at the 4-mm stage could be distinguished based on their ethylene evolution. Chemical name used: gibberellic acid (GA3).
Ursula K. Schuch, Jack J. Kelly, and Trent Teegerstrom
Capillary mats and overhead sprinkler irrigation were used in a simulated retail environment to maintain annual and perennial plants in containers for various time periods during summer and winter. Combining the results from both seasons, four species with dense canopies had larger canopy sizes when maintained on the capillary mats, three species requiring more drainage had larger canopies with overhead irrigation, and five species were unaffected by irrigation systems. Substrate electrical conductivity was higher for some species in winter for plants on capillary mats, conserving fertilizer compared with overhead irrigation. Most species tolerated either irrigation system well. Water application was 71% less in summer and 62% less in winter to maintain plants on capillary mats compared with overhead irrigation. An economic analysis compared the investment required for setup and maintenance of plants in a retail situation using hand watering, overhead sprinkler, or capillary mat irrigation. The partial budget indicates that capillary mats are a labor-saving alternative to hand watering in a retail nursery and will compensate for the higher initial investment within less than 1 year. The overhead sprinklers are the most cost-effective system of the three because of less costly initial set-up and maintenance than the capillary mats; however, they are not a true alternative to hand watering in a retail situation because they interfere with customer traffic and worker activities.
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.