In 1992, Hurricane Andrew destroyed over 1000 mature trees in the City of North Miami, located 50 mi north of the storm center. The cleanup cost over $1,000.000. Most of the tree failures were caused by structural faults: co-dominant leaders, narrow limb attachment, included bark, over-lifting, hatracking, poor vertical limb placement, crown imbalance, overly-dense crowns, crossing and in-growing branches. All could have been corrected with proper pruning. Action was taken to reduce future damage. The city arborist made a complete, computerized inventory of all trees on public property, creating a data-base with all structural problems identified. These were prioritized so the worst could be addressed first. After any pruning work was done on a city tree, a follow-up evaluation was made, and any additional pruning needed was scheduled. Pruning followed the recommendations of state specialists and three county extension agents with the University of Florida Cooperative Extension Service. City workers were taught using lectures, demonstrations, site visits, CES publications, and individualized instruction. In addition, all new trees purchased were grades FL Fancy or FL no. 1, based on Grades and Standards for Nursery Plants; such trees require little or no corrective pruning at planting and mature as structurally-sound trees which resist wind damage. Two later storms (1993, 1999) produced winds in North Miami similar to those of Hurricane Andrew. Together they destroyed only 35 trees which cost $35,000 to remove. These data demonstrate that following CES pruning recommendations reduces storm damage to trees, saving money and preserving the urban forest canopy.
Intermediate-day plants (IDP) flower most rapidly and completely under intermediate photoperiods (e.g., 12 to 14 h of light), but few species have been identified and their flowering responses are not well understood. A variety of experiments was conducted to determine how light controls flowering and stem extension of Echinacea purpurea `Bravado' and `Magnus'. Both cultivars flowered most completely (79%) and rapidly and at the youngest physiological age under intermediate photoperiods of 13 to 15 h. Few (14%) plants flowered under 10- or 24-h photoperiods, indicating E. purpurea is a qualitative IDP. Plants were also induced to flower when 15-h dark periods were interrupted with as few as 7.5 min of low-intensity lighting (night interruption, NI). Flowering was progressively earlier as the NI increased to 1 h, but was delayed when the NI was extended to 4 h. Stem length increased by 230% as the photoperiod or NI duration increased, until plants received a saturating duration (at 14 h or 1 h, respectively). At macroscopic visible bud, transferring plants from long days to short days reduced stem extension by up to 30%. Flowering was inhibited when the entire photoperiod was deficient in blue or red light and was promoted in a far-red deficient environment, suggesting that phytochrome and cryptochrome control flowering of E. purpurea. Because of our results, we propose the flowering behavior of IDP such as E. purpurea is composed of two mechanisms: a dark-dependent response in which flowering is promoted by a short night, and a light-dependent response in which flowering is inhibited by a long day.
Miami-Dade County Extension, with the participation of University of Florida faculty and other speakers, created a Certified Course in Horticulture in 2005. The intended audience is landscape maintenance and installation personnel, tree trimming employees, home gardeners, city and parks employees, and others who want horticultural knowledge. The goal of the program was to educate the participants in basic horticultural practices such as: plant selection and installation—including palms and turf; plant propagation; landscape design; pruning; irrigation; fertilization; pest control, and related topics. The class was limited to 60 participants due to space constraints. The response surpassed all expectations with 58 people completing the course and 40 passing the final exam. Eight months after the end of the program, a follow-up telephone survey was conducted with 24 participants. The results reflect that a high percentage of the participants are still using the correct landscape techniques. In order to reach as many people as possible a video or CD with the entire course is going to be prepared.
The ornamental horticulture industry in South Carolina has expanded significantly over the last decade. Today, concerns regarding environmental and public health, and stricter regulations of pesticide use, are creating incentives for growers to evaluate alternative methods of pest control. Nursery producers currently use an array of chemicals in an attempt to control pests including insects, weeds, and diseases. Integrated pest management (IPM) provides an opportunity to reduce chemical reliance. The overall objective of this extension program is to collect and collate information relevant to the implementation of an IPM program. The first year, 1989-90, surveys were developed to determine key factors related nursery pest management. Types of data collected included: key pest species; pest-plant relationships; grower action responses to pest problems; types and frequency of pesticide use. The second year, 1990-91, involved implementing IPM strategies such as: cultural methods; use of horticultural oils, soaps, and lower risk pesticides; and spot treatment applications to help maintain pest populations below economically damaging levels. Improvements in pest management included; reduced chemical applications, reduced associated environmental risks, and maintenance of aesthetic quality of plants.
For many long-day plants (LDP), adding far red light (FR, 700 to 800 nm) to red light (R, 600 to 700 nm) to extend the day or interrupt the night promotes extension growth and flowering. Blue light (B, 400 to 500 nm) independently inhibits extension growth, but its effect on flowering is not well described. Here, we determined how R-, FR-, or B-deficient (Rd, FRd, or Bd, respectively) photoperiods influenced stem extension and flowering in five LDP species: Campanula carpatica Jacq., Coreopsi ×grandiflora Hogg ex Sweet, Lobelia ×speciosa Sweet, Pisum sativum L., and Viola ×wittrockiana Gams. Plants were exposed to Rd, FRd, Bd, or normal (control) 16-hour photoperiods, each of which had a similar photosynthetic (400 to 700 nm) photon flux. Compared with that of the control, the Rd environment promoted extension growth in C. carpatica (by 65%), C. ×grandiflora (by 26%), P. sativum (by 23%), and V. ×wittrockiana (by 31%). The FRd environment suppressed extension growth in C. ×grandiflora (by 21%), P. sativum (by 17%), and V. ×wittrockiana (by 14%). Independent of the R: FR ratio, the Bd environment promoted stem extension (by 10% to 100%) in all species, but there was little or no effect on flowering percentage and time to flower. Extension growth was generally linearly related to the incident wide band (100 nm) R: FR ratio or estimated phytochrome photoequilibrium except when B light was specifically reduced. A high R: FR ratio (i.e., under the FRd filter) delayed flower initiation (but not development) in C. carpatica and C.×grandiflora and inhibited flower development (but not initiation) in V.×wittrockiana. Therefore, B light and the R: FR ratio independently regulate extension growth by varying magnitudes in LDP, and in some species, an FRd environment can suppress flower initiation or development.
Environments with a low red (R, 600 to 700 nm) to far-red (FR, 700 to 800 nm) ratio (e.g., with high plant density) promote stem elongation, and a high R: FR suppresses it. While FR light promotes stem extension, it is also required for rapid, uniform flowering of many long-day plants. We investigated how a new FR filter [creating a FR-deficient (FRd) environment] influenced plug growth and subsequent flowering of pansy (Viola ×wittrockiana `Crystal Bowl Yellow'), petunia (Petunia ×hybrida `Carpet Pink'), impatiens (Impatiens wallerana `Accent Rose'), snapdragon (Antirrhinum majus `Liberty Scarlet'), and tomato (Solanum lycopersicon `Beefmaster'). One-week-old seedlings were placed under three filter treatments with 16-h photoperiods: the FRd filter, a neutral-density filter (N) that transmitted a similar PPF, and transferring plugs from the N to the FRd filter when leaves of each species began to touch (7 to 11 days later). The predicted phytochrome photoequilibria under the FRd and N filters was 0.80 and 0.72, respectively. After 25 to 35 days at 20 °C, node number and stem (or petiole for pansy) length were collected. Twenty plants of each species and filter treatment were then transferred to 4-inch pots and grown under natural photoperiods (14 to 15 h) at 20 °C until flowering. Compared to plants continually under the N filter, stem length under the FRd filter was significantly reduced in impatiens (by 11%), pansy (by 18%), petunia (by 34%), snapdragon (by 5%), and tomato (by 24%). Flowering of plants from plugs under the FRd filter was delayed by 2 to 3 days for snapdragon, petunia, and pansy. Filter treatment of plugs had no significant effect on flower number or plant height at flower.
The study evaluated the relationship of spur vs. extension shoot leaf area and light interception to apple (Malus {XtimesX} domesticaBorkh.) orchard productivity. Fifteen-year-old `Marshall McIntosh'/M.9 trees had significantly greater leaf area and percentage of light interception at 3-5 and 10-12 weeks after full bloom (AFB) than did 4-year-old `Jonagold'/Mark trees. Despite significant increases in leaf area and light interception with canopy development, linear relationships between total, spur, and extension shoot canopy leaf area index (LAI) and 1) light interception and 2) fruit yield were similar at both times. Mean total and spur canopy LAI and light interception were significantly and positively correlated with fruit yield; however, extension shoot LAI and light interception were poorly correlated with yield. In another study total, spur and extension shoot canopy light interception varied widely in five apple production systems: 15-year-old central leader `Redchief Delicious' MM.111, 15-year-old central leader `Redchief Delicious' MM.111/M.9, 16-year-old slender spindle `Marshall McIntosh' M.9, 14-year-old `Jerseymac' M.9 on 4-wire trellis, and 17-year-old slender spindle `MacSpur' M.9. Yields in these orchards were curvilinearly related to total and extension shoot canopy light interception and decreased when total light interception exceeded 60% and extension shoot interception exceeded 25%. Fruit yields were linearly and highly correlated (r 2 = 0.78) with spur light interception. The findings support the hypothesis that fruit yields of healthy apple orchards are better correlated with LAI and light interception by spurs than by extension shoots. The results emphasize the importance of open, well-illuminated, spur-rich tree canopies for high productivity.
PRECODEPA was formed with the purpose of coordinating research and extension to improve small-farm potato production. The program involves 9 countries in North, Central America and the Caribbean with the cooperation of the International Potato Center (CIP). Research and extension work was planed based on identified bottlenecks. Work was coordinated when similar bottlenecks were identified in different regions and/or countries. The project strategies emphasized the following: training of personnel to coordinate the work between extension and research; development of integrated pest management (IPM) practices; technology generation and validation trials on farmers' fields, and market development for commercialization purposes. The success of this unique program should serve as a model for similar agricultural projects in the future.
Sponsored by the ASHS Commercial Horticulture Extension Working Group (CHEX), this colloquium brought together eight leaders in high tunnel research. Gathered from across the country, the speakers discuss topics ranging from integrated pest