bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparison of Previsits for Youth Field Trips to Public Gardens
Authors: Haynes Cynthia , Pieper Jon C. , Trexler Cary
Published: December 2018

Creating effective learning experiences with limited educational resources has compelled educators to maximize the value of field trips. A common problem associated with field trips is anxiety felt by students in new surroundings, a situation that can distract students and adversely affect learning. Previsit activities before a field trip may reduce such anxiety and thereby increase attentiveness and learning. The objective of this study was to compare the effects of traditional and Internet-based previsit activities on learning and attitudes of fourth and fifth graders after a field trip to a public garden. Students in three classes were evaluated. Half of each class was assigned to one of the two previsit treatments. Three forms of assessments were used to measure the students' perceptions and learning: 1) observations were made to determine how many students remained on-task during the field trip, 2) 12 close-ended (Likert scale) questions were given to students and used to evaluate attitudinal responses the day after the field trip, and 3) seven open-ended questions were given to students and used to evaluate cognitive responses 1 week after the field trip. Attitudinal responses were identical between treatments. Observational data indicated that students subjected to the Internet-based previsit activity exhibited fewer off-task behaviors. Internet-based previsit activities increased cognitive scores in students compared to the traditional previsit activities for two of seven questions. The advantages of the Internet-based previsit activities may be the result of enhanced opportunity for self-directed learning and access to additional content.
Changing Times for Eastern United States Blackberries
Authors: Clark John R.
Published: December 2018

Eastern U.S. blackberries (Rubus subgenus Rubus) have advanced in recent years in production and quality of cultivar choices. Mainly a pick-your-own and local sales item of the early 1990s and before, the increased presence of blackberries in retail grocery stores in the last 10 years has broadened the market for this small fruit. Cultivars that can be shipped and have extended shelf life have been the cornerstone of this expansion. Also, off-season production in Mexico has provided fruit for retail marketing during most months of the year. Further advances in production, marketing, and consumption can be achieved with the continuation of improved cultivar development and expansion of production technology.
Trends in U.S. Sweet Orange, Grapefruit, and Mandarin-type Cultivars
Authors: Stover Ed , Castle William , Chao Chih-Cheng T.
Published: December 2018

The world market for citrus (Citrus spp.) products has undergone dramatic shifts over the last decade. These shifts are influencing development and planting of new citrus cultivars. Seedlessness and very easy peeling have become paramount in mandarin types (C. reticulata and hybrids), and new cultivars are being developed through plant breeding and selection of new sports. In both sweet orange (C. sinensis) and grapefruit (C. paradisi), essentially all important cultivars are derived from a single original hybrid of each fruit type, and plant improvement has focused on selection of sports with redder color and extended maturity. The existence of many active citrus breeding programs makes it likely that we will continue to see evolution of new citrus cultivars over the foreseeable future.
Climatic Trends and Potato Late Blight Risk in the Upper Great Lakes Region
Authors: Baker Kathleen M. , Kirk William W. , Stein Jeffrey M. , Andresen Jeffrey A.
Published: December 2018

Concern in the agricultural community over observed and projected climate change has prompted numerous studies on the possible implications for crop yields. However, relatively little work has focused on disease management. In the upper Great Lakes region of the United States, late blight (Phytophthora infestans) of potato (Solanum tuberosum) is a temporally sporadic disease, occurring only when microclimate conditions within the canopy are favorable and inoculum is present. This and other studies indicate that historical climatological trends in the upper Great Lakes region have resulted in warmer and wetter growing season conditions, as well as local increases in precipitation totals and in the frequency of days with precipitation. Consequently, the risk of potato late blight is increasing. Historical trends in hourly weather variables and potato late blight risk as expressed by a modified Wallin disease severity value index were analyzed at seven regional weather stations from 1948–99. All sites showed significant trends in at least one of the risk estimates. While late blight risk was greatest at all locations in August, periods of increasing risk occurred across the region particularly during July. The increases in disease risk appeared to be associated with upward trends in dry bulb and dew point temperature at nearly all of the stations, especially during July and August. Increased risk of potato late blight has implications for extension agents and commercial horticulturists that include increased emphasis on grower education and application of integrated disease management techniques.
A Comparison of Instruments and Contract Services Used to Calculate Degree-days
Authors: Richardson Matthew L. , Caron Dewey M.
Published: December 2018

Various instruments and contract services can be used to calculate degree-days. This study compared instruments and services to the Wescor Biophenometer, an instrument used by cooperators of the Southeast Pennsylvania IPM Research Group (SE PA IPM RG) throughout Delaware and southeastern Pennsylvania for 10 years. Instruments evaluated in the study were the Wescor Biophenometer Datalogger, Avatel HarvestGuard, Avatel Datascribe Junior, Davis Weather Monitor II, Accu-Trax, and the HOBO H8 Pro Temperature Data Logger. The services were SkyBit and national weather data. Different combinations of instruments and services were used at three locations in Pennsylvania and four locations in Delaware over a 2-year period. We checked the degree-day accumulation of each instrument and service weekly and made statistical comparisons among the instruments and services at each site. To further construct a comparison of the instruments, we noted distinctive qualities of each instrument, interviewed the manufacturers, and received feedback from SE PA IPM RG members who used the instruments. We evaluated the instruments' algorithms, durability, cost, temperature sampling interval, ease of use, time input required by the user, and other distinctive factors. Statistically, there were no significant differences in degree-day accumulations between the Biophenometer, Harvest-Guard, Datascribe, Weather Monitor II, Skybit, or weather service data. However, cost and time required to access/interpret data and personal preference should be major considerations in choosing an instrument or service to measure degree-days.
Turfgrass Seed and Sod Establishment on Soil Amended with Biosolid Compost
Authors: Linde Douglas T. , Hepner Lawrence D.
Published: December 2018

Using composted biosolid waste as a soil amendment for turfgrass is becoming a common method for disposing of municipal waste. This study was conducted to evaluate turfgrass seed and sod establishment on subsoil amended with various rates of biosolid compost. To a soil that had its A-horizon removed, biosolid compost derived from sewage sludge was incorporated at rates of 0, 132, 270, and 402 yard3/acre. A fifth treatment included a single application of fertilizer at time of sowing. Kentucky bluegrass (Poa pratensis) was seeded immediately after treatment application. The treatments were repeated on an adjacent area using kentucky bluegrass sod. For 1.5 years, turfgrass percent cover, color, density, and weeds were evaluated. Overall, the compost performed well as a soil amendment for turfgrass. A 2- to 3-inch depth of compost appeared to be the best incorporation rate for the soil and compost used in this study. High salinity and excessive ammonium nitrogen (NH4-N) levels in the compost-amended soil at the time of establishment caused a 2- to 3-week delay in seed and sod establishment. After the 2 to 3 weeks, the compost-amended plots outperformed the one-time fertilized plots in turfgrass color and density. Turf managers may want to account for the delay in establishment when incorporating a 60-day-cured compost.
Acetic Acid Fumigation of Apple Rootstocks and Tree Fruit Scionwood to Remove External Microflora and Potential Plant Pathogens
Authors: Sholberg Peter L. , Randall Paul , Hampson Cheryl R.
Published: December 2018

Acetic acid (AA) fumigation of rootstocks and dormant shoots was explored as a method of eliminating plant pathogens from propagation material. Dormant shoots were tested in early winter to determine the rate of AA vapor that they could tolerate before being damaged. Apricot (Prunus armeniaca), apple (Malus ×domestica), and peach (Prunus persica) shoots collected from a single site in Dec. 1999 tolerated 30, 12, or 6 mg·L–1 AA, respectively. Vineland 3 (V3) and Malling-Merton 106 (MM.106) rootstock liners fumigated with 1 mg·L–1 AA were adequately surface-sterilized although the effect on growth was not recorded. A similar experiment with Malling 9 (M9) rootstocks showed that 12 mg·L–1 AA would eliminate most surface microorganisims from roots although it delayed shoot growth when the trees were planted. The higher 15 mg·L–1 rate delayed tree growth and appeared to kill some trees. The 12 mg·L–1 rate prevented growth of Erwinia amylovora and Pseudomonas syringae pv. syringae bacteria on shoots even when an enrichment technique was used to detect them. Finally, when 96 `Jonagold' apple shoots known to be infected by Podosphaera leucotricha were fumigated with AA in 2001, none developed powdery mildew, although 99% of the control shoots did. These promising results suggest that further research should be done toward adapting AA fumigation for use by commercial nurseries.
Differential Responses in Color Changes and Softening of `Florida 47' Tomato Fruit Treated at Green and Advanced Ripening Stages with the Ethylene Antagonist 1-Methylcyclopropene
Authors: Hurr Brandon M. , Huber Donald J. , Lee James H.
Published: December 2018

In this study, ripening characteristics, including color change and softening, were determined for tomato (Lycopersicon esculentum `Florida 47') fruit at immature-green through light red stages of development and subsequently treated with 1 μL·L–1 1-methylcyclopropene (1-MCP). Special attention was directed at comparing the responses of immature and mature-green fruit. Surface color and whole fruit firmness were measured every other day. 1-MCP delayed or slowed color changes and softening in fruit of every maturity class, with differences between control and treated fruit evident immediately following 1-MCP application for 24 h at 20 °C. Fruit treated with 1-MCP at early maturity stages (immature-green, mature-green, and breaker) exhibited an extended delay in external red pigment accumulation compared with control fruit. Fruit of all maturity classes developed acceptable final hue values (hue angle ≤55°), and the time required to reach these values declined with advancing fruit maturity. Immature-green fruit treated with 1-MCP did not attain an acceptable degree of softening during the specified storage periods examined before deteriorating due to shriveling and pathogen proliferation. 1-MCP-treated mature-green and breaker stage fruit did recover to acceptable firmness (5–10 N) and hue values but exhibited a severely reduced storage life thereafter compared with untreated fruit of equal maturity. Fruit at turning and more advanced stages exhibited reduced rates of softening and color development when treated with 1-MCP, yet they attained firmness and color values within the range of acceptability for commercial use. Fruit treated with 1-MCP at pink and light-red stages of ripening developed normal external color and exhibited significantly extended postharvest life due largely to a significant retention in firmness when compared to control fruit. Based on the studies described for `Florida 47' tomato fruit, 1-MCP would appear to be of little benefit and possibly detrimental if applied to early maturity fruit, most notably greens and breakers, due to irreversible limitations in the capacity of these fruit to soften to acceptable values. In sharp contrast, more advanced stage fruit, particularly pink and light red, responded to 1-MCP with significantly extended shelf-life due to retention of firmness.
Four Levels of Soil Water Depletion Minimally Affect Carambola Phenological Cycles
Authors: Al-Yahyai Rashid , Schaffer Bruce , Crane Jonathan H. , Davies Frederick S.
Published: December 2018

Phenological cycles were determined for carambola (Averrhoa carambola) trees in a gravelly loam soil at four different soil water depletion (SWD) levels in containers and in an orchard in southern Florida. The phenological cycles of young trees grown in containers were not as well defined as those of mature trees in an orchard. Shoot extension of trees in the orchard and containers was observed from the first week of March until the third week of December. Two peak flowering periods occurred during the first week of March, and from mid-September to mid-October. The major fruit harvest periods were August and December. Shoot flushing, extension shoot growth, flowering, and fruiting showed little response to irrigation at four SWD levels. This lack of response was likely caused by sufficient soil water due to precipitation and capillary rise from the high water table located about 1–2 m below the soil surface. Regardless of the lack of SWD effects on phenological cycles of carambola, the periodicity of shoot flushing, extension shoot growth, flowering, and fruiting and the intensity of these phenological events elucidated in this study should provide useful guidelines for carambola orchard management in southern Florida.
Onion Response to Drip Irrigation Intensity and Emitter Flow Rate
Authors: Shock Clinton C. , Feibert Erik B.G. , Saunders Lamont D.
Published: December 2018

Although an irrigation onset criterion for drip-irrigated onion (Allium cepa) has been determined, the optimal irrigation intensity has not been examined. Some authors have argued that very high irrigation frequencies with low amounts of water are needed to maximize crop responses. Long-day, sweet Spanish onions were grown on 44-inch beds with two double rows spaced 1.8 ft apart and a drip tape buried 4 inches deep in the bed center. Onions were submitted to eight treatments as a combination of four irrigation intensities (1/16, 1/8, 1/4, and 1/2 inch of water per irrigation) and two drip tape emitter flow rates (0.5 and 0.25 L·h–1) on silt loam in 2002 and 2003. The 1/16-, 1/8-, 1/4-, and 1/2-inch irrigation intensities had irrigations scheduled up to eight times, four times, twice, or once per day, respectively, to replenish soil water potential to –20 cbar as needed. Each plot was independently and automatically irrigated if the soil water potential at 8-inch depth was equal to or lower than –20 cbar. This resulted in an average of 564, 269, 121, and 60 irrigations over 107 days for the 1/16-, 1/8-, 1/4-, and 1/2-inch irrigation intensities, respectively. Onions were harvested, stored, and evaluated for yield and grade after 75 days of storage. Averaged over irrigation intensities, the drip tape with 0.5 L·h–1 emitters had significantly higher total yield, marketable yield, and colossal onion yield than the tape with 0.25 L·h–1 emitters. Averaged over emitter type, the 1/2-inch irrigation intensity had higher total and marketable onion yields than the 1/16- and 1/8-inch intensities. Averaged over emitter type, the 1/2-inch irrigation intensity resulted in the highest super colossal and colossal onion yield. Onions grown with an irrigation intensity of 1/2 inch and drip tape with emitter flow rate of 0.5 L·h–1 produced total yields of 50.0 ton/acre, marketable yields of 48.8 ton/acre, super colossal yield of 1.05 ton/acre, and colossal yield of 13.9 ton/acre. Interactions between irrigation intensities and emitter flow rates were nonsignificant for the number of irrigations, water applied, average soil water potential, or onion yield and grade. There was no significant difference in average soil water potential between treatments. There was no significant difference in total water applied plus precipitation between treatments, with, on average, 32.3 and 31.1 inches applied in 2002 and 2003, respectively. Onion evapotranspiration from emergence to onion lifting totaled 34.6 and 37.3 inches in 2002 and 2003, respectively.
Plant Science Graduate Students: Demographics, Research Areas, and Recruitment Issues
Authors: Darnell Rebecca L. , Cheek Jimmy G.
Published: December 2018

Graduate student enrollment in the plant sciences has decreased over the past several years, and there is increasing interest in recruitment/retention strategies. Before successful strategies can be implemented, however, the status of current plant science graduate programs needs to be determined. Survey data on graduate student demographics, research area, support levels, current recruitment strategies, and career opportunities were collected from 23 plant science graduate programs. Overall, 55% of graduate students in plant sciences were male and 45% were female; approximately 60% were domestic and 40% were international. Cellular/molecular biology and breeding/genetics were the two disciplines that had the greatest number of graduate students and the greatest number of job opportunities. Although most programs cited financial support as the biggest obstacle to recruitment, there was not a strong correlation between graduate student number/program and stipend amount. However, other funding factors besides stipend amount; such as stipend number, the guarantee of multiple years of support, the funding of tuition waivers, and health insurance costs, likely impact student number. As more of these costs are shifted to faculty, there appears to be an increasing inability and/or reluctance to invest grant funds (which support 60% of the plant science graduate students) in graduate student education. These data suggest that the decline in plant science graduate student enrollment may not be directly due to low stipend amounts, but rather to shifting of more of the total cost of graduate training to faculty, who may be unable/unwilling to bear the cost. There is also a clear shift in the research focus of plant science graduate students, as postdoctoral and career opportunities are weighted towards molecular biology/genetics, leaving the more applied plant science areas particularly vulnerable to low graduate enrollment.
Sam's Dilemma: A Decision Case for Training Horticultural Volunteers
Authors: Jutila Stephanie Gale , Meyer Mary Hockenberry
Published: December 2018

A decision case was developed and used to train volunteers at the Minnesota Landscape Arboretum. The case presents a real life dilemma for volunteers at public horticultural institutions, allowing volunteers to experience a realistic decision making process, applicable to their volunteer jobs. Volunteers are able to identify that the decisions they make in their volunteer position ultimately affect the institution as a whole including visitors and volunteers. The case is written as an active learning tool for use in a volunteer orientation or continuing education workshop. Volunteers benefit from an enhanced understanding of the importance of communication of changes in life commitment, including how these changes relate to their particular volunteer interests.
Harvest and Postharvest Quality of Short-day Onions in Variety Trials in Georgia, 2000–03
Authors: Boyhan George E. , Purvis Albert C. , Randle William M. , Torrance Reid L. , Cook M. Jefferson , Hardison Greg , Blackley Ronald H. , Paradice Heath , Hill C. Randy , Paulk J. Thad
Published: December 2018

Short-day onion (Allium cepa) variety trials were conducted in southeastern Georgia from 2000–03. Data collected and evaluated included total yield, graded yield, harvest date, number of seedstems, number of doubles, number of onion centers, bulb shape, disease incidence, bulb pungency, and storability in controlled atmosphere (CA) storage. Fifty-eight varieties were evaluated in the trials with 10 varieties appearing in all 4 years. Twenty-nine varieties appeared only once in the trials. Eight varieties had jumbo yields (≥3-inch diameter) that were not significantly different from the greatest jumbo yielding variety in 2 of the 4 years of testing and included `Century', `EX 19013', `Georgia Boy', `Mr. Buck', `Sapelo Sweet', `Savannah Sweet', `Sweet Vidalia', and `WI-609'. Early season varieties were strongly daylength dependent with foliar lodging occuring early and uniformly. Late season varieties were more prone to bacterial infection particularly if postharvest heat curing was employed. Although significant differences between varieties for seedstems (flower formation) and bulb doubling occurred almost every year, environmental conditions were an important part of their development. Five varieties had seedstems in 2 of the 3 years seedstems were prevalent that did not differ from the greatest number of seedstems for that year and included `Cyclops', `Georgia Boy', `Mr. Buck', `Pegasus', and `SSC 6372 F1'. `Sapelo Sweet' and `Sweet Advantage' had more than 5% bulb doubling in 3 years of the trials. Pungency as measured by pyruvate analysis ranged from 1.1 to 5.4 μmol·g–1 fresh weight (FW) over the 4 years of trials. There were nine varieties that were, for 2 years or more, among the greatest in percent marketable onions after 4.5 months of CA storage: `Georgia Boy', `Granex 1035', `Granex 33', `Ohoopee Sweet', `Sapelo Sweet', `Savannah Sweet', `Sweet Melissa', `Sweet Melody', and `SRO 1000'.
Evaluation of Pansy Cultivars as Bedding Plants to Select the Best-of-class
Authors: Kelly Richard O. , Deng Zhanao , Harbaugh Brent K. , Schoellhorn Rick K.
Published: December 2018

Florida is one of the top wholesale producers of bedding plants, and in 2003 was ranked fourth in annual bedding plant production and fifth in potted pansy/viola production. Evaluation of pansy cultivars is vital for continued growth of the industry. We evaluated 210 cultivars of pansy (Viola ×wittrockiana) (164 new cultivars) in replicated class tests at the University of Florida's Gulf Coast Research and Education Center at Bradenton, Fla., from 2000–04 to determine the best-of-class and use them in future trials to compare against new entries in the same class. In this report, we provide objective plant measurements of vegetative and floral characteristics as well as subjective performance ratings. Subjective ratings were on a 1 to 7 scale with the highest rating of 7 for excellent. In general, overall performance ratings (combined foliage, flower, arthropod, and disease ratings) ≥5.5 were considered outstanding. Pansy cultivars were grouped into classes based on flower color and pattern. Best-of-class selections that had an outstanding overall performance rating in one or more contested trials, never falling below 5.0 in other contested trials, were: (black class) `Accord/Banner Black Beauty', (blue shades/tints class) `Nature Blue', (blue with blotch class) `Nature Ocean', (mix class) `Panola Clear Mixture', (pink shades/tints with blotch class) `Nature Pink Shades', [purple (dark), blue-violet with white cap class] `Nature Beacon', [purple (dark), blue-violet/white face with blotch class] `Panola Purple With Face', (purple with light eye class) `Baby Bingo Lavender Blue', (white class) `Nature White', (yellow class) `Nature Yellow', (yellow with blotch and purple, blue-violet cap class) `Iona Purple & Yellow With Blotch', (yellow with blotch and red cap class) `Bingo Red & Yellow', (yellow with blotch and red cap class) `Panola Yellow With Blotch', (yellow with dark veins class) `Whiskers Yellow'. We believe these cultivars would perform well in the southern U.S. or areas of the world with similar heat and cold hardiness zones.
Experiences with Wastes and Composts in Nursery Substrates
Authors: Chong Calvin
Published: December 2018

During the past 20 years, the Ornamental Nursery Research Program at the former Horticultural Research Institute of Ontario (now part of the University of Guelph) has been conducting applied research dealing with environmentally friendly and sustainable nursery production practices with emphasis on container production. The use of farm, industrial, and consumer waste by-products as amendments in nursery substrates has been a major focus. The program has evaluated hundreds of potting mixes derived from individual or combined, raw or composted waste by-products including spent mushroom compost, turkey litter compost, paper mill sludge, municipal waste compost, corrugated cardboard, apple pomace, wood chips from pallets, pulverized glass, and various types of tree barks. With few exceptions, all the above waste by-products tested under our cultural conditions provided acceptable to excellent container-growing media, often in amounts exceeding 50% and sometimes up to 100% by volume in No. 2 containers (6 L), even despite initially elevated and potentially toxic contents of soluble salts [expressed in terms of electrical conductivity measured up to 8.9 dS·m-1 in 1 substrate: 2 water (by volume) extracts] in many of the substrates. A key to these successful results is that salts leach quickly from the containers to benign levels (∼1.0 dS·m-1) with normal irrigation practices. High initial pH in most waste-derived substrates (up to 8.9) has had little or no discernible effect on growth of a wide assortment of deciduous nursery species. By-products such as paper mill sludge and municipal waste compost with soluble salts contents typically ranging from 0.8 to 2.0 dS·m-1, also provide acceptable rooting media provided salts are leached before use to values ≤0.2 dS·m-1. The porosity and aeration characteristics of waste-derived substrates tend to be comparable to, or better than, those of bark.
Healthy Substrates Need Physicals Too!
Authors: Bilderback Ted E. , Warren Stuart L. , Owen James S. , Albano Joseph P.
Published: December 2018

Many research studies have evaluated potential organic and mineral container substrate components for use in commercial potting substrates. Most studies report results of plant growth over a single production season and only a few include physical properties of the substrates tested. Furthermore, substrates containing predominantly organic components decompose during crop production cycles producing changes in air and water ratios. In the commercial nursery industry, crops frequently remain in containers for longer periods than one growing season (18 to 24 months). Changes in air and water retention characteristics over extended periods can have significant effect on the health and vigor of crops held in containers for 1 year or more. Decomposition of organic components can create an overabundance of small particles that hold excessive amounts of water, thus creating limited air porosity. Mineral aggregates such as perlite, pumice, coarse sand, and calcined clays do not decompose, or breakdown slowly, when used in potting substrates. Blending aggregates with organic components can decrease changes in physical properties over time by dilution of organic components and preserving large pore spaces, thus helping to maintain structural integrity. Research is needed to evaluate changes in container substrates from initial physical properties to changes in air and water characteristics after a production cycle.
Variability in the Physical and Chemical Properties of Retail Potting Media
Authors: Wiberg Amanda , Koenig Richard , Cerny-Koenig Teresa
Published: December 2018

Popular press articles report that consumers often experience inconsistent results with retail potting media; however, few reports in the popular or scientific literature have quantified the variability in media properties. The purpose of this study was to assess the variability in physical and chemical properties among different brands of retail potting media and within certain brands. Twenty-four different packages of branded media, and multiple packages of five brands, were acquired from nine regional and national retail chain stores located in the Salt Lake City, Utah, area. Samples were analyzed for five physical and nine chemical properties. The coefficients of variation (cvs) among brands for initial gravimetric water content, bulk density, porosity, water retention, and air space were 85%, 74%, 21%, 59%, and 44%, respectively. The cvs among brands for saturated media (SM) pH, SM extract electrical conductivity (EC), nitrate-nitrogen (NO3-N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), total carbon (C), total nitrogen (N), and C:N ratio were 18%, 81%, 132%, 153%, 96%, 78%, 71%, 36%, 45%, and 49%, respectively. Only one of the 24 brands met all published standards for chemical properties of premium media. Thirteen of the brands did not meet standards for NO3-N; 12 did not meet standards for pH; and six did not meet standards for EC. There was more variation in physical and chemical properties among brands than within a brand of media. Label information describing media composition was not consistent with certain physical and chemical properties. No recommendations can be made which would allow consumers to select media that meets published standards. These results indicate better awareness of and/or adherence to standards is needed by the retail media industry to improve product quality and consistency.
Mechanical Harvesting Capacity in Sweet Orange Is Increased with an Abscission Agent
Authors: Burns Jacqueline K. , Buker Richard S. , Roka Fritz M.
Published: December 2018

An abscission agent [5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP)] was applied to `Hamlin' and `Valencia' orange (Citrus sinensis) trees at concentrations ranging from 0 to 500 ppm in a volume of 300 gal/acre. Four days after application, fruit were mechanically harvested with either a trunk shake-and-catch or a continuous canopy shake-and-catch system commercially used in Florida. Harvesting conditions were varied by limiting the actual trunk shake time of the trunk shaker to 2, 4, or 7 seconds, or by altering the ground speed of the canopy shaker (1.0, 1.5, or 2.0 mph). In general, increasing duration of shake and the application of CMNP increased percent mature fruit removal and decreased the amount of fruit remaining in the tree. Increasing CMNP concentration decreased fruit detachment force but increased post-spray fruit drop. Comparison of short duration shake times in CMNP-applied trees with trees harvested at longer durations either sprayed or not sprayed with CMNP indicated no significant difference in percent mature fruit removal. The results demonstrate that CMNP application increases harvesting capacity of trunk and canopy shakers by reducing time necessary to harvest each tree while maintaining high percent mature fruit removal.
Floral Product Behaviors and Their Influence on Consumer Floral Purchase Frequency
Authors: Huang Li-Chun
Published: December 2018

Product behavior represents how consumers perceive and use a product. Its importance in predicting consumer buying behavior is well documented in marketing research. There are, however, no data available investigating the role of product behavior in the floral market. This study addressed this deficiency. Data were first analyzed using factor analysis to extract the principal determinants of product behavior in the floral market. As a result, six primary behavioral factors were identified and named as: “using flowers as daily essentials,” “perceived product value,” “negative attitude toward flowers,” “using flowers as gifts,” “eventbased usage,” and “experience in receiving flowers.” The effects of these extracted behavioral factors on consumer flower purchase frequency were then further investigated with multinomial logistic regression analysis. Analytical results revealed that behaviors “using flowers as daily essentials” and “using flowers as gifts” forced consumers to become heavy users in the floral market. Conversely, “negative attitude toward flowers” negatively affected the floral purchase frequency. Experimental results in this study also suggest that promoting a positive attitude toward flowers is essential in encouraging consumers to become flower users. The intended use of flower product purchase, whether for personal use or as gifts, was the main factor affecting the frequent purchasing of flowers.
Fruit Firmness of Pickling Cucumber Cultivars
Authors: Suojala-Ahlfors Terhi
Published: December 2018

Fruit firmness is one of the most important quality aspects in the production of pickling cucumbers (Cucumis sativus) for industry. This study compared the fruit firmness of different cultivars and evaluated the usability of different firmness variables. Firmness of fruit of five to six cultivars from a cultivar experiment was measured penetrometrically over 3 years. The maximum load needed to penetrate the skin, distance at maximum load, load at the end of the measurement, and the mean work during the whole measurement were recorded. Different variables gave a versatile impression of the fruit texture. Although there were some differences in the measured values each year, the ranking of the cultivars was similar each year. Cultivars Celine and Servus had the firmest skin and overall texture. `Aubade' and `Carine' had lower skin firmness but the inner part of the fruit of `Aubade' was very firm. `Etude' was similar to `Carine'. `B2590', measured in only 2 years, had lowest firmness both in skin and flesh. The results show that penetrometric measurement of fruit firmness is a suitable method for analyzing the texture of cucumbers intended for pickling.
Resurgence of Soilborne Pests in Doublecropped Cucumber after Application of Methyl Bromide Chemical Alternatives and Solarization in Tomato
Authors: Gilreath James P. , Motis Timothy N. , Santos Bielinski M. , Noling Joseph W. , Locascio Salvadore J. , Chellemi Daniel O.
Published: December 2018

Field studies were conducted during four consecutive tomato (Lycopersicon esculentum) -cucumber (Cucumis sativus) rotations to examine the longterm residual effects of tomato methyl bromide (MBr) alternatives on soilborne pests in double-cropped cucumber. Four treatments were established in tomato fields: a) nontreated control; b) MBr + chloropicrin (Pic) (67:33 by weight) at a rate of 350 lb/acre; c) tank-mixed pebulate + napropamide at 4 and 2 lb/acre, respectively, followed by 1,3-dichloropropene (1,3-D) + Pic (83:17 by volume) at 40 gal/acre; and d) napropamide at 2 lb/acre followed by soil solarization for 7 to 8 weeks. Each of the following seasons, cucumber was planted in the same tomato plots without removing mulch films. For nutsedge [purple nutsedge (Cyperus rotundus) and yellow nutsedge (C. esculentus)] densities, napropamide followed by solarization plots had equal control (≤15 plants/m2) as MBr + Pic during all four cropping seasons. However, nematode control with solarization was inconsistent. Marketable yield data proved that fumigation in tomato fields with either MBr + Pic or pebulate + napropamide followed by 1,3-D + Pic had a long-term effect on double-cropped cucumber.
Identification of Preharvest Desiccants for Use in Onion Production
Authors: Arboleya Jorge E. , Masabni Joseph G. , Particka Michael G. , Zandstra Bernard H.
Published: December 2018

Dry bulb onion (Allium cepa) leaves may not dry down normally and bulbs may not attain dormancy during adverse growing seasons. An effective method of artificial leaf desiccation is needed to complement mechanical harvesting and onion conditioning for storage. Desiccants were tested in 1993, 1994, 1995, 2001, 2002, 2003 on onion leaves prior to harvest, and bulb quality was evaluated after 5 months or more of storage. Carfentrazone, diquat, and paraquat desiccated onion foliage well but increased bulb rot and reduced the percentage of marketable bulbs after storage. Bromoxynil and endothall desiccated onion foliage significantly without inducing rot or reducing the percentage of marketable bulbs. Copper sulfate and pelargonic acid increased desiccation of onion foliage but were not sufficiently effective for field use. Neither reduced the percentage of marketable bulbs. If bromoxynil or endothall were labelled for onion desiccation, they could be applied 10-14 days before harvest to enhance natural leaf senescence and facilitate mechanical harvest.
Drip-applied Soil Fumigation for Freesia Production
Authors: Gerik James S.
Published: December 2018

Field trials were conducted to test fumigants as alternatives to methyl bromide (MB) for production of hybrid freesia (Freesia × hybrida). One trial compared rates of 1,3-dichloropropene (DP) combined with chloropicrin (CP); the second trial compared iodomethane (IM) together with CP, DP:CP, and furfural with and without metham sodium; and the third trial compared rates and formulations of IM:CP to the standard MB:CP treatments. Most treatments reduced populations of Pythium spp. and controlled weeds compared to the untreated controls. Formulations of IM:CP reduced the incidence of disease caused by Fusarium oxysporum. Treatments of IM:CP performed as well as MB:CP, and treatments of DP:CP performed as well as IM:CP. Presently only the DP, CP and metham sodium formulations are registered for use on ornamental crops. Registration of the IM formulations will improve the options available to cut flower growers for management of plant pathogens and weeds.
Survival of Salmonella spp. on the Surfaces of Fresh Tomatoes and Selected Packing Line Materials
Authors: Allen Raina L. , Warren Benjamin R. , Archer Douglas L. , Schneider Keith R. , Sargent Steven A.
Published: December 2018

Multi-state outbreaks of salmonellosis due to the consumption of contaminated fresh tomatoes (Lycopersicon esculentum) have recently occurred in the United States. This study investigated the survival of a five-serovar (serotype) Salmonella cocktail artificially inoculated onto tomato and packing line surfaces when held at various temperature and relative humidity (RH) combinations over 28 days. Packinghouse surfaces included stainless steel, polyvinyl chloride (PVC), sponge rollers, conveyor belts, and unfinished oak wood surfaces. Packinghouse climates were generated to simulate conditions in Florida during late spring (30 °C/80% RH) and fall/winter (20 °C/60% RH) months. Additionally, survival of Salmonella on tomatoes in standard ripening room conditions (20 °C/90% RH) was evaluated. Recovery of inocula was by a vigorous shake/hand rub method. After 28 days, Salmonella populations remained detectable on tomato surfaces regardless of environmental conditions. Inoculated Salmonella populations tested at spring conditions declined to undetectable levels on all packing line materials by day 11, with the exception of the unfinished oak, which reached undetectable levels by day 21. In contrast, inoculated Salmonella populations tested at fall/winter conditions declined to undetectable levels on sponge rollers and conveyor belts by day 7 and day 21, respectively. Stainless steel, PVC, and wood surfaces supported the survival of detectable populations of Salmonella over the 28-day sampling period. Results of this study demonstrate the potential for Salmonella to persist on tomato and packing line surfaces under common environmental conditions.
Remote Sensing of Shaded Area in Vineyards
Authors: Johnson Lee , Scholasch Thibaut
Published: December 2018

Airborne multispectral image data were compared with intercepted photosynthetic photon flux (PPF) in commercial winegrape (Vitis vinifera) vineyards of Napa Valley, Calif. An empirically based calibration was applied to transform raw image pixel values to surface reflectance. Reflectance data from the red and near-infrared spectral regions were combined into a normalized difference vegetation index. Strong linear response was observed between the vegetation index and PPF interception ranging from 0.15 to 0.50. Study results suggest the possibility of using optical remote sensing to monitor and map vineyard shaded area, thus providing spatially explicit input to water budget models that invoke evapotranspiration crop coefficient based calculations.
Securing the Food Chain: The 2000-04 Southeastern U.S. Fresh Produce Food Safety Train-the-Trainer Program
Authors: Osborne Dennis J. , Sanders Douglas C. , Ward Donn R. , Rushing James W.
Published: December 2018

Between 2000 and 2004, a 12-state consortium in the southeastern United States used a “train-the-trainer” effort to introduce good agricultural practices (GAPs) to the region's fresh produce growers, packers, and consumers. Supported by the National Food Safety Initiative, the consortium created and implemented training by using a program and supporting materials specifically applicable to conditions and commodities in southern states. Because several factors distinguish the southeastern U.S. fresh produce industry from that of other regions in the U.S., a region-specific training program addressing distinguishing factors was needed. Distinguishing factors include: 1) southeastern U.S. producers are typically grower-packers, with some notable exceptions in Florida and Texas; 2) most such producer entities are seasonal, have their own packinghouse operation, are small-scale in that they pick what they grow and pack and often use migrant and seasonal labor; 3) modern worker training, sanitary practice, and facilities and supervisory expertise are either somewhat limited or completely lacking; and 4) the use of seasonal and migrant labor dictates the use of Spanish language interpreters and training. To meet fresh produce food safety training needs for the region, project leaders created a 329-page training program and associated PowerPoint presentation-containing compact disc, nine four-page crop-specific brochures relating GAPs to crop “groups,” a Spanish language handwashing video and a new model recall program for the fresh produce industry. The leveraging effect of this train-the-trainer effort ultimately reached nearly 20,000 people in this multi-disciplinary, multi-state, integrated project, thus expanding and reinforcing regional cooperative extension efforts.
Companion Crop and Planting Configuration Effect on Onion
Authors: Hatterman-Valenti Harlene M. , Hendrickson Paul E.
Published: December 2018

Field trials were conducted to evaluate the effect of planting configurations (raised bed and no bed) and reservoir tillage on onion (Allium cepa) yield and grade when a cereal grass or cool-season broadleaf species was used as a companion crop. Total onion yield, the number of plants harvested, percentage of single centers, and cull-sized bulb yields did not differ among planting configurations. However, planting onion seed in raised beds with reservoir tillage resulted in more large-diameter bulbs compared to planting without a bed configuration. Raised beds also had fewer small-sized bulbs than the non-bed configuration. Companion crop influence on onion yield and grade varied among environments (location plus year). In general, canola (Brassica napus) as a companion crop increased the yield of small-sized bulbs and decreased total yield and the yield of large-sized bulbs. These results were attributed to poor canola control from the initial bromoxynil plus oxyfluorfen application because each label restricts application until onions have reached the two true-leaf stage. Onion yield and grade with barley (Hordeum vulgare) as a companion crop was similar to that of onion with no companion crop except during 2002 (Carrington) when rain delayed the postemergence grass herbicide application and lowered onion yield.
An After-school Gardening Club to Promote Fruit and Vegetable Consumption among Fourth Grade Students: The Assessment of Social Cognitive Theory Constructs
Authors: O'Brien Suzanne A. , Shoemaker Candice A.
Published: December 2018

An eight-lesson gardening and nutrition curriculum with a hands-on gardening emphasis was taught as an after-school program to determine the effect it had on increasing children's nutrition knowledge, fruit and vegetable preference, and improving children's self-efficacy and outcome expectations for gardening and for consuming fruit and vegetables. Seventeen fourth grade students participated in the experimental group as part of an after-school gardening club, and 21 fourth grade students served as the control group. Nutrition knowledge, preference, self-efficacy, outcome expectations, as well as demographic measures were obtained at baseline and end-program. There were no differences in nutrition knowledge scores between or within groups at baseline or at end-program. However, baseline scores were high (>7 out of 10 possible) for both groups. Both groups indicated a high preference for fruit at baseline and end-program. Vegetable preference did not increase over the course of the program for both groups. At baseline, measurements of gardening self-efficacy and outcome expectations were significantly different between the groups. The experimental group was able to maintain high self-efficacy and outcome expectations scores during the program, but the control group's scores increased significantly for gardening self-efficacy and outcome expectations at the end-program assessment. Further research to clarify aspects of gardening (i.e., season, harvesting, crops grown) that have the greatest impact on influencing preference, self-efficacy and outcome expectations is needed.
Development of a New Harvest Container for Wild Blueberries
Authors: Forney Charles F. , Eaton Leonard J. , Gao Leigh
Published: December 2018

Increasing the size of containers used to transport wild lowbush blueberry (Vaccinium angustifolium) fruit from the field to the processing facility has the potential to increase handling efficiency. Currently the wild blueberry industry uses a standard 18-inch-long × 15-inch-wide × 5-inch-deep plastic container that holds about 20 lb of fruit. This study examined the development of a new, pallet-sized high-capacity blueberry container and determined its effects on fruit quality following harvesting, transport, and processing. Laboratory studies on the effects of packing depth of berries on fruit quality demonstrated that container depths of 14.2 inches were damaging to fruit 24 hours following harvest, transport, and holding under ambient conditions, while depths of 7.1 inches were not. In commercial trials with larger pallet-sized prototype containers, fruit depths of up to 10 inches were not damaging to fruit under otherwise typical commercial handling conditions. Dumping fruit from the 10-inch-deep pallet-sized containers onto conveyer belts at the processing facility caused minimal damage to the fruit. In addition, fruit crushing that occurred in the large pallet-sized containers was similar to that occurring in the standard 20-lb plastic containers currently used by the industry. Results of these studies indicate that large pallet-size blueberry containers with a depth of 10 inches could be used without causing significant damage to fresh fruit during harvest, transport, and processing. Thus as a whole, the adoption of this type of container would improve handling efficiency and potentially the quality of the fruit.