bluuebunny/crossref_metadata_2025 huggingface dataset:
Yield and Quality of Field-grown Celosia and Globe Amaranth Cut Flowers at Four Plant Densities
Authors: Green Sabine R. , Picchioni Geno A. , Murray Leigh W. , Wall Marisa M.
Published: December 2018

Field-grown cut and dried flowers could provide a high-value crop selection for New Mexico. We conducted a 1-year field study to evaluate flower yield and quality characteristics of common globe amaranth (Gomphrena globosa), ‘Strawberry Fields’ globe amaranth (Gomphrena haageana), cockscomb celosia (Celosia argentea var. cristata ‘Chief Mix’), and wheat celosia (Celosia spicata ‘Pink Candle’). Within-row spacing of 15 or 20 cm combined with two-row or three-row per bed plantings resulted in field planting densities ranging from 66,670 to 120,010 plants/ha of common globe amaranth and ‘Strawberry Fields’ globe amaranth, and 100,005 to 200,010 plants/ha of cockscomb and wheat celosia. All but cockscomb celosia produced four harvests that began 22 May and ended 18 Oct., depending on species. Both globe amaranth species had a 5- to 6-month harvest season, two to three midseason to late-season peak harvests, and over 1000 harvested stems totaling 1.4 to 1.8 kg dry weight per 1.5-m2 plot across the season. Both celosia species had a 4.5-month harvest season, one early summer peak harvest, and fewer than 300 harvested stems totaling 0.6 to 0.7 kg dry weight per plot for the year. Seasonally progressive increases in flowering stem length of both globe amaranth species and wheat celosia, and in flowering stem diameter of both globe amaranth species and cockscomb celosia, were observed. Flowering head size of both globe amaranth species and of wheat celosia varied little with harvest season, whereas the head diameter of cockscomb celosia increased with the season. Postharvest flower retention after mechanical impact was about 2% higher for common globe amaranth than it was for ‘Strawberry Fields’ globe amaranth, decreased by about 6% from early to later harvests for both celosia species, and was inversely related to the head size of both globe amaranth species and cockscomb celosia. Despite the wide range in planting density, the density effect was largely limited to cockscomb celosia. For that species, three-row planting (high density) increased the total number of spray flower (multiple head) stems, provided longer stems later into the season and wider heads midway into the season, and prolonged the production of spray stems (15-cm spacing only). Results demonstrate that these four species are excellent candidates as new specialty crops in semiarid conditions.
Nodulation of Seaside Alder Topdressed with Controlled-release Fertilizer
Authors: Beddes Taun , Kratsch Heidi A.
Published: December 2018

Seaside alder (Alnus maritima) is a rare species adapted for ornamental use. It can be produced easily by commercial growers, and when soil-inoculated in nursery containers, will form root nodules containing nitrogen (N)-fixing bacteria in the genus Frankia. It has been demonstrated that nodulation within this species can be controlled by the amount of N plants receive from a liquid source; however, granular controlled-release fertilizers (CRF) also are commonly used by commercial growers, and information is not available on CRF effects on nodulation. We sought to determine the application rate of CRF that will maximize nodulation of seaside alder while sustaining acceptable plant health and growth. Inoculated containerized plants were topdressed with CRF at eight application rates from 0 to 32.0 g per container. A control group of uninoculated plants received the manufacturer's prescribed rate of 6.0 g per 6-inch-diameter standard round pot. Regression analysis revealed that treatment with 2.0 g of CRF maximized root nodule formation (a mean of 26 nodules), while nodulation was inhibited at CRF rates ≥4.0 g. Plant growth parameters and leaf N content of inoculated plants treated with 2.0 g of CRF were similar to those of uninoculated plants receiving the prescribed rate of CRF (P < 0.05); nitrate-nitrogen leaching from pots containing 2.0-g CRF-treated plants was minimal. We conclude that vigorous nodulated plants of seaside alder can be produced, with minimal nitrate leaching, by providing CRF at lower than prescribed rates.
Reducing Time and Expense to Recycle Perlite for Repeat Use in Greenhouse Tomato Operations
Authors: Hanna Hanna Y.
Published: December 2018

Planting greenhouse tomatoes (Solanum lycopersicum) in the same perlite more than once without reconditioning to restore medium loose structure, desalination to remove excess salt, and disinfection to guard against pest contamination is risky, and replacing the perlite to produce every new crop is costly. Reconditioning and treating perlite with hot water at a minimum cost provides a favorable solution for both problems and saves natural resources. A study was conducted in a 30 × 96-ft greenhouse in Spring 2007, 2008, and 2009 (January–July) to evaluate three methods for perlite recycling cost, desalination efficiency, and effects on tomato yield at three or four fruit per cluster. Each recycling method consisted of two components: the reconditioning action and the hot water treatment. The three recycling methods included no stir/sift then disinfect, stir then disinfect, and sift then disinfect. Perlite recycled with the no stir/sift then disinfect method was not reconditioned before the hot water treatment. Instead, it was agitated with a nozzle mounted on a pressure washer wand during the hot water treatment. Perlite recycled with the stir then disinfect method was reconditioned first with an auger mounted on an electric drill and then treated with hot water. Perlite recycled with the sift then disinfect method was reconditioned first by sifting the perlite with a homemade apparatus and was then treated with hot water. Recycling perlite with the no stir/sift then disinfect method reduced labor input by 49% and 81% compared with the stir then disinfect and the sift then disinfect methods, respectively. The no stir/sift then disinfect method reduced recycling cost by 22% and 50% compared with the other two methods, respectively. Perlite that was not reconditioned (no stir/sift) had higher nitrate-nitrogen (NO3-N) before hot water treatment than the stirred perlite and equal NO3-N to the sifted perlite. Hot water treatment significantly reduced medium electrical conductivity, NO3-N, potassium, and sodium. Tomatoes grown in perlite recycled with any of the three methods produced similar marketable and cull yields and fruit weight. Pruning fruit to three per cluster increased marketable yield, fruit weight, and reduced cull yield. There was no significant recycling method × cluster pruning interaction for yield components, indicating that all recycling methods had similar effects on tomato yield at three or four fruit per cluster. We conclude that the no stir/sift then disinfect method is less time consuming, more economical, and has no negative impact on yield. Tomatoes grown with three fruit per cluster in perlite recycled with any of the three methods produced greater marketable yield, less cull yield, and heavier fruit than tomatoes grown with four fruit per cluster.
Economic Returns in Plasticulture Tomato Production from Crucifer Cover Crops as a Methyl Bromide Alternative for Weed Management
Authors: Bangarwa Sanjeev K. , Norsworthy Jason K. , Rainey Ronald L. , Gbur Edward E.
Published: December 2018

The phase-out of methyl bromide required an effective and economically viable alternative for weed management in polyethylene-mulched tomato (Solanum lycopersicum). A field experiment was conducted to compare economics of tomato production associated with crucifer (Brassicaceae) cover crops under low-density polyethylene mulch (LDPE) and virtually impermeable film (VIF) mulch with a standard treatment of methyl bromide:chloropicrin (67:33) at 350 lb/acre. Three crucifer cover crops, ‘Seventop’ turnip (Brassica rapa), ‘Pacific Gold’ oriental mustard (Brassica juncea), and Caliente [a blend of brown mustard (B. juncea) and white mustard (Sinapis alba)], were evaluated in combination with hand-weeding. Because of marginal weed control from crucifer cover crops, hand-weeding cost in all cover crop plots, regardless of mulch type, increased from $380.54/acre to $489.10/acre over that in methyl bromide plots. However, total weed management costs in the untreated control and cover crops with LDPE treatments were $17.82/acre to $111.33/acre lower than methyl bromide. Because of mulch expenses, VIF mulch increased the total weed management cost by $328.16/acre over LDPE mulch in the untreated control and cover crop treatments. Because of equivalent marketable yield, gross returns ($21,040.43/acre) were identical in all treatments. Preplant fumigation with methyl bromide provided $6260.90/acre of net returns in tomato production. The untreated control, ‘Seventop’ turnip, ‘Pacific Gold’ oriental mustard, and Caliente mustard under LDPE treatment were $54/acre, $54/acre, $98/acre, and $147/acre more profitable, respectively, than methyl bromide. However, in all other treatments under VIF, net returns relative to methyl bromide were reduced from $181/acre to $274/acre. Therefore, regardless of soil amendment with crucifer cover crops, hand-weeding can serve as an economically viable alternative to methyl bromide for weed control in LDPE-mulched tomato production, depending on the nature and level of pest infestation, labor availability, and wages.
Tolerance of Transplanted Seashore Dropseed to Pre- and Postemergence Herbicides
Authors: Baldos Orville C. , DeFrank Joseph , Sakamoto Glenn
Published: December 2018

Field experiments were conducted to assess the tolerance of seashore dropseed (Sporobolus virginicus) to pre- and postemergence herbicides labeled for roadside right-of-way use. Dithiopyr (0.25 and 0.50 lb/acre a.i.), trifluralin + isoxaben (2.0 + 0.5 and 4.0 + 1.0 lb/acre a.i.), oxyfluorfen (0.25 and 0.50 lb/acre a.i.), oxadiazon (2.0 and 4.0 lb/acre a.i.), and granular table salt (99% sodium chloride, 1% sodium silicoaluminate; 83% of particles 0.5–0.25 mm in diameter, 400 lb/acre a.i.) were applied at 2 and 84 days after transplanting (DAT). Pre-emergence weed control with crop response measures as visual foliar injury ratings and aboveground biomass accumulation were recorded 38 days after the second application of herbicides (DAH2). Crop response to postemergence herbicides aminopyralid (1.10 lb/acre a.i.), triclopyr (3.0 lb/acre a.i.), a prepackaged mix of carfentrazone + (4-chloro-2-methylphenoxy)acetic acid + mecoprop + dicamba (0.02 + 1.11 + 0.22 + 0.11 lb/acre a.i.), and sulfosulfuron (0.06 lb/acre a.i.) applied at 70 and 98 DAT included visual foliar injury ratings and aboveground biomass accumulation at 28 DAH2. Although all pre-emergence herbicides (except table salt) exhibited acceptable weed control ratings, only oxadiazon and oxyfluorfen showed exceptional weed control and safety. The postemergence herbicide sulfosulfuron was the least injurious to seashore dropseed. The mixture of carfentrazone + (4-chloro-2-methylphenoxy)acetic acid + mecoprop + dicamba and triclopyr were the most injurious to seashore dropseed and should only be used as a directed spray treatment. An unintended overapplication of aminopyralid was phytotoxic, but it did not lead to complete plant death at 28 DAH2. These data identified oxadiazon, oxyfluorfen, and sulfosulfuron as safe and effective for establishing transplanted seashore dropseed plugs.
Plant Growth Retardant Drench Efficacy Is Not Affected by Substrate Containing Parboiled Rice Hulls
Authors: Currey Christopher J. , Camberato Diane M. , Torres Ariana P. , Lopez Roberto G.
Published: December 2018

Parboiled rice hulls have become a more common component of soilless growing substrates. While there have been reports that some organic substrate components reduce the efficacy of plant growth retardant (PGR) drenches, the influence of rice hulls on PGR drenches is unknown. ‘Callie Deep Yellow’ calibrachoa (Calibrachoa ×hybrid) and ‘Delta Orange Blotch’ pansy (Viola wittrockiana) were planted in containers filled with substrate containing (v/v) 80% peat and 20% perlite or parboiled rice hulls. After planting, 2.5-fl oz drenches containing deionized water or ancymidol, paclobutrazol, or uniconazole were applied to plants grown in each substrate. Plant growth retardants, but not substrate, affected growth rate, and final stem length of calibrachoa and plant height of pansy. There were no differences in regression model coefficients between substrates within PGR applications for plant height (pansy) or stem length (calibrachoa) over the course of the experiment. Paclobutrazol (2.0 or 4.0 ppm) and uniconazole (1.0 or 2.0 ppm), but not ancymidol (1.0 or 2.0 ppm) suppressed final stem length of calibrachoa. Final height of pansy was suppressed by each concentration of paclobutrazol and uniconazole and 2.0 ppm ancymidol, but not 1.0 ppm ancymidol. Based on these results, rice hulls did not reduce PGR drench efficacy when included as a substrate component comprising (v/v) 20% of a substrate.
Preference of Sweetpotato Whitefly Adults to Cucumber Seedlings Grown under Two Different Light Sources
Authors: Shibuya Toshio , Komuro Junki , Hirai Norio , Sakamoto Yoshiko , Endo Ryosuke , Kitaya Yoshiaki
Published: December 2018

We evaluated the preference of adult sweetpotato whitefly [SPWF (Bemisia tabaci biotype B)] to cucumber (Cucumis sativus) seedlings grown under fluorescent lamps (FLs) or metal-halide lamps (MLs) that provided a spectrum similar to that of natural light. Cucumber seedlings were grown under FLs or MLs at a photosynthetic photon flux of 350 μmol·m−2·s−1 in a 12/12-hour light/dark cycle. The red:far red (R:FR) ratio of FL was 7.0 and that of ML was 1.2. Pairs of cucumber seedlings, one grown under FLs and the other under MLs, were then placed in cages and about 100 SPWF adults were released. There were significantly fewer SPWF adults on the FL cucumber seedlings (36%) than on the ML seedlings (64%) 24 hours after release. FL cucumber seedlings had higher chlorophyll content and thicker leaves than ML seedlings. The lower attractiveness of the FL cucumber seedlings was probably due to changes in morphologic characteristics such as the leaf color and thickness resulting from high R:FR illumination of FL. The fact that light quality affects the plant attractiveness to herbivores should be considered in selecting light sources for transplant production under artificial light.
Meeting Learning Objectives through Service-Learning: A Pomology Case Study
Authors: Garner Lauren C.
Published: December 2018

Undergraduate students enrolled in the introductory pomology course at California Polytechnic State University, San Luis Obispo, CA, from 2007 to 2010, participated in a service-learning project. Students helped the community organization, the California Rare Fruit Growers (CRFG), teach grafting skills to San Louis Obispo County high school students and community members. At the end of each quarter, pomology students completed evaluations of their experience. Results of these evaluations were used to improve teaching methodology and the experience in which the students participated. Self-reported and instructor evaluations of the service-learning project demonstrated that students increased their grafting knowledge and skills, their confidence in learning new skills, and their interest in fruit science and community involvement. The service-learning project enabled students to meet course learning objectives of understanding and becoming experienced in horticultural techniques, such as grafting, and to meet university learning objectives of developing critical thinking and communication skills and increasing community involvement.
Yield and Fruit Quality Traits of Rambutan Cultivars Grafted onto a Common Rootstock and Grown at Two Locations in Puerto Rico
Authors: Goenaga Ricardo , Jenkins David
Published: December 2018

The globalization of the economy, increased ethnic diversity, and a greater demand for healthy and more diverse food products have opened a window of opportunity for the commercial production and marketing of tropical fruit, including rambutan (Nephelium lappaceum). There is a lack of formal experimentation to determine yield performance and fruit quality traits of rambutan cultivars. Eight rambutan cultivars (Benjai, Gula Batu, Jitlee, R-134, R-156Y, R-162, R-167, and Rongren) grown on an Ultisol and an Oxisol soils were evaluated for 5 years at Corozal and Isabela, PR, respectively. There was a significant difference in the number and weight of fruit per hectare between locations, averaging 415,103 fruit/ha and 13,826 kg·ha−1, respectively, at Corozal and 167,504 fruit/ha and 5149 kg·ha−1, respectively, at Isabela. At Corozal, ‘R162’ had the highest 5-year mean for number and weight of fruit per hectare, but this cultivar was not significantly different from the rest except for ‘Benjai’ and ‘R-156Y’, which had significantly lower values. At Isabela, cultivars Gula Batu and R-162 had significantly higher number of fruit per hectare but the latter was not different from ‘Benjai’. Overall, there were no differences in soluble solids concentration except for cultivars Gula Batu and R-156Y, which had significantly lower values at both locations. Cultivar R-162 had higher number and weight of fruit per hectare and high soluble solids concentration at both locations, making it suitable for planting in various agroenvironments particularly on Ultisols typical of the humid tropics.
Establishment and Turf Qualities of Warm-season Turfgrasses in the Mediterranean Region
Authors: Severmutlu S. , Mutlu N. , Shearman R.C. , Gurbuz E. , Gulsen O. , Hocagil M. , Karaguzel O. , Heng-Moss T. , Riordan T.P. , Gaussoin R.E.
Published: December 2018

Warm-season turfgrasses are grown throughout the warm humid, sub-humid, and semiarid regions. The objective of this study was to determine the adaptation of six warm-season turfgrass species and several of their cultivars to Mediterranean growing conditions of Turkey by evaluating turfgrass establishment rate, quality, color, and percentage of turfgrass cover. Information of this nature is lacking and would be helpful to turfgrass managers and advisers working in the region. A study was conducted over a 2-year period in two locations of the Mediterranean region of Turkey. The warm-season turfgrass species studied were bermudagrass (Cynodon dactylon), buffalograss (Buchloë dactyloides), zoysiagrass (Zoysia japonica), bahiagrass (Paspalum notatum), seashore paspalum (Paspalum vaginatum), and centipedegrass (Eremochloa ophiurioides). Tall fescue (Festuca arundinacea) was included as a cool-season turfgrass species for comparison. Twenty cultivars belonging to these species were evaluated for their establishment, turfgrass color and quality, spring green-up, and fall color retention. Bermudagrass, bahiagrass, and seashore paspalum established 95% or better coverage at 1095 growing degree days [GDD (5 °C base temperature)], buffalograss and centipedegrass at 1436 GDD, and ‘Zenith’ and ‘Companion’ Zoysiagrass had 90% and 84% coverage at Antalya after accumulating 2031 GDD. ‘Sea Spray’ seashore paspalum; ‘SWI-1044’, ‘SWI-1045’, ‘Princess 77’, and ‘Riviera’ bermudagrass; ‘Cody’ buffalograss; and ‘Zenith’ zoysiagrass exhibited acceptable turfgrass quality for 7 months throughout the growing season. ‘Argentine’ and ‘Pensacola’ bahiagrass; ‘Sea Spray’ seashore paspalum; and ‘SWI-1044’ and ‘SWI-1045’ bermudagrass extended their growing season by retaining their green color 15 days or longer than the rest of the warm-season cultivars and/or species in the fall. The warm-season species stayed fully dormant throughout January and February. Zoysiagrass and buffalograss cultivars showed early spring green-up compared to the other warm-season species studied. Results from this study support the use of warm-season turfgrass species in this Mediterranean region, especially when heat stress and water limitations exist. Tall fescue did not survive summer heat stress necessitating reseeding in fall.
After-ripening, Stratification, and Perigynia Removal Enhance Pennsylvania Sedge Germination
Authors: McGinnis Esther E. , Meyer Mary H.
Published: December 2018

Pennsylvania sedge (Carex pensylvanica) has horticultural and restoration potential, but the achenes are difficult to germinate due to complex dormancy requirements. This study identified treatments to overcome physiological dormancy and determined light and temperature requirements for optimum germination. We first tested the effects of perigynia removal and light on achene germination. In the second experiment, achenes were subjected to varying durations of dry-cold or dry-warm storage conditions and a presowing soak in gibberellic acid (GA3). In a third experiment, we studied whether storage conditions, cold stratification, and sowing temperatures affected germination. Pennsylvania sedge germination was improved by dry-warm storage, perigynia removal, cold stratification, and germination in light.
Willingness to Buy New Ethnic Produce Items: A Study of Latino Consumers from Mexico and Puerto Rico in the Eastern United States
Authors: Govindasamy Ramu , Puduri Venkata S. , Simon James E.
Published: December 2018

The purpose of this study was to predict Latinos', consumers from Mexico and Puerto Rico, willingness to buy ethnic produce recently introduced or new to market. Specifically, we analyzed and compared socioeconomic characteristics of 542 Mexican and Puerto Rican consumers and expressed value judgments on their willingness to buy ethnic produce that has been recently introduced or new to market. This study was based on a primary data set collected from interviewing 542 Latino consumers (Mexico and Puerto Rico origin). A bilingual questionnaire was prepared in Spanish and English for Mexicans and Puerto Ricans in 16 states (Connecticut, Delaware, Florida, Georgia, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Pennsylvania, Rhode Island, South Carolina, Vermont, and Virginia) and Washington, DC. Attributes that contributed toward willingness to buy new ethnic produce include respondent's expenditure on total produce and ethnic produce, perceptions such as the importance of store availability, language, willingness to buy locally grown, organic, genetically modified, and country of origin labeled produce items. This information will assist market intermediaries and farmers better understand Latino consumers' (Mexico and Puerto Rico group) perceptions and factors that drive willingness to buy ethnic produce that is recently introduced or new to market.
Effectiveness and Audience Analysis of University of Minnesota Extension's Electronic Yard and Garden Newsletter
Authors: Foord Karl E. , Zlesak David C. , Bartholomay Tom G. , Meyer Mary H.
Published: December 2018

An online survey of readers of the University of Minnesota Extension's electronic Yard & Garden Newsletter (Y&G News) revealed significant differences between respondents on the basis of current employment and Master Gardener affiliation. Fifty-three percent of the respondents were general public (GP); 31% were Master Gardener trained (MGT), followed by full-time horticultural employees (FTE) and part-time horticultural employees (PTE) , each of whom made up to 8% of the 500 readers who responded to the survey. Overall, respondents indicated a high level of satisfaction with the newsletter (4.8 out of 5.0), and 81% indicated that the newsletter had provided them with “specific information that they found extremely valuable” in the past 2 years. PTE and MGT respondents rated the newsletter as significantly more useful than did the GP. FTE placed greatest value on timely information related to pest control. GP subscribers indicated that annuals and perennials were the horticultural topics they were most interested in for future issues. All subscribers highly value the newsletter for its usefulness and timeliness and indicated that the newsletter improved their ability to make horticultural decisions. Ninety-nine percent would recommend the newsletter to a friend. The mission of the Y&G News and content changes based on survey responses and available resources are discussed.
Spray-on-mulch Technology for Intensively Grown Irrigated Apple Orchards: Influence on Tree Establishment, Early Yields, and Soil Physical Properties
Authors: Cline John , Neilsen Gerry , Hogue Eugene , Kuchta Shawn , Neilsen Denise
Published: December 2018

Use of and interest in organic mulches for both integrated fruit production (IFP) and organic fruit production is increasing given recent efforts to reduce pesticide inputs and improve soil health. A series of four experiments was conducted in the southern interior of British Columbia over 5 years to investigate the use of a spray-on-mulch (SOM) slurry, comprised primarily of recycled waste newsprint fiber, as an effective method to control excessive weed competition and enhance tree establishment and performance. In four experiments, ‘Gala’, ‘Granny Smith’, ‘Ambrosia’, and ‘Honeycrisp’ apple (Malus ×domestica) trees on ‘Malling 9’ (‘M.9’) rootstock were exposed to a series of treatments including a glyphosate check, SOM waste paper, SOM over an organic underlay, SOM incorporated with dichlobenil or tackifier, SOM over black landscape fabric, rowcover cloth, or polyethylene plastic. SOM provided superior weed control in comparison with the glyphosate check treatment, a standard orchard practice in many modern orchards in North America. SOM application over compost, paper, and especially over cloth barriers were found to be more effective weed barriers than SOM alone. In comparison with glyphosate checks, SOM improved tree growth during tree establishment. Although the addition of dichlobenil provided season-long weed control, tree growth was diminished in comparison with SOM alone and remained similar to that of the glyphosate checks. There was little or no benefit of including a 2.5% tacking agent to help improve SOM integrity and long-term surface stability. When applied to bearing 4-year-old trees, SOM provided similar tree vigor as glyphosate checks over four growing seasons. The addition of landscape fabric, plastic, or cloth underlay material in combination with SOM improved tree vigor in formative years, but this benefit diminished over time. SOM-treated trees had greater cumulative yields over glyphosate checks after 3 years of production. SOM provided significant temperature moderation during the summer and winter months and provided moisture conservation during the summer. There were few SOM effects on plant nutrient status.
Growth and Development of ‘Eckespoint Classic Red’ Poinsettia in Biodegradable and Compostable Containers
Authors: Lopez Roberto G. , Camberato Diane M.
Published: December 2018

Biodegradable, compostable, and traditional plastic containers were evaluated for production of ‘Eckespoint Classic Red’ poinsettia (Euphorbia pulcherrima), a long-term greenhouse crop (12–16 weeks transplant to finish, depending on cultivar). Containers were rated for appearance and durability during the 14-week production period and plant quality parameters were measured at anthesis. Plastic, rice hull, wheat starch-derived bioresin, and molded fiber containers remained unchanged in appearance and integrity and received a rating of 5 (1–5 rating scale, where 1 = container integrity compromised substantially and 5 = container was intact, no visible changes in terms of color or construction). However, straw, coconut coir, composted cow manure, and Canadian sphagnum moss and wood pulp containers had an average rating of 2.9, 2.7, 1.4, and 1.6, respectively. Both shoot and root dry weights were greatest in plants produced in molded fiber and straw containers. The root to shoot dry weight ratio and days to anthesis was not significantly different among container types. Bract area index (a measurement derived to estimate bract area) was greatest for plants produced in molded fiber containers and lowest for those produced in the wheat starch containers. When adjusted for container height, final plant height was greatest in molded fiber containers and lowest in wheat starch containers. Plants produced in molded fiber containers, on average, exhibited the greatest height, bract area index, and total root and shoot weight, with no visible changes to container integrity. Based on these results, plant quality was not negatively impacted by any of the seven containers, though marketability of finished plants can be affected by container integrity.
Brassicaceae Cover Crops Affect Seed Germination and Seedling Establishment in Cucurbit Crops
Authors: Ackroyd Victoria J. , Ngouajio Mathieu
Published: December 2018

Field and laboratory bioassay studies were conducted to determine the impact of Brassicaceae cover crops on cucurbit germination percentages and stand counts. A 2-year field study in southwestern Michigan examined the effect of oilseed radish (Raphanus sativus var. oleiferus), oriental mustard (Brassica juncea), and yellow mustard (Sinapis alba) green manures on muskmelon (Cucumis melo Group reticulatus) stand. All three cover crops reduced direct-seeded muskmelon stand count as well as transplant survival. Stand count for direct- seeded muskmelon was greater than 85% for control and methyl bromide treatments and less than 41% for cover crop treatments. Oilseed radish had the greatest effect with 0% muskmelon stand in both years. The use of transplants improved muskmelon stand establishment. However, stand count (less than 45% to 50%) was still unacceptable. In bioassays, muskmelon, cucumber (Cucumis sativus), and honeydew melon (Cucumis melo Group inodorus) seeds were exposed to either non-lyophilized or lyophilized root and shoot aqueous extracts of oilseed radish. Germination percentages and radicle elongation measurements showed both extracts impacted all three crops to varying degrees. Muskmelon germination was least sensitive to the extracts, followed by cucumber, then honeydew. Cucumber and muskmelon root growth was equally inhibited by non-lyophilized shoot extract, while honeydew growth was mildly stimulated at 5% and 12.5% concentrations. Overall, non-lyophilized root extract showed stronger inhibition on seed germination than non-lyophilized shoot extract, while the reverse was true of lyophilized extracts. In general, non-lyophilized extracts had far greater impact on germination percentages and radicle elongation than lyophilized extracts. These results suggest species and tissue dependent toxicity of the cover crops as well as differential susceptibility of the cucurbit crops tested. Therefore, a plant-back period longer than the 8 days used in this study should be observed after cover crop incorporation before cucurbit seeding or transplanting.
Impact of Fungicide Program and Powdery Mildew Resistance in Three Varieties of Pumpkin
Authors: Coolong Timothy , Seebold Kenneth
Published: December 2018

The effects of fungicide program and varietal resistance on the development of cucurbit powdery mildew [PM (Podosphaera xanthii)] in pumpkin (Cucurbita pepo) were tested in 2009 and 2010 in Lexington, KY. Three fungicide programs consisted of a no-fungicide control, low input (chlorothalonil), and high input (chlorothalonil alternated with myclobutanil) were applied to three varieties of pumpkin with different levels of cucurbit PM resistance. Varieties tested were Howden, Aladdin, and Camaro, which had no, moderate, and high levels of cucurbit PM resistance, respectively. There were no significant variety by fungicide program interactions for yield, number fruit per acre, and average fruit weight in both years. In 2009 and 2010, variety significantly affected yield. Yield increases corresponded to the level of cucurbit PM resistance. The high-resistance variety, Camaro, had the greatest yields in both years, while Howden, with no PM resistance, had the lowest yields. In 2010, yield significantly increased with the intensity of fungicide program. With the exception of cull percentage in 2009, there were no fungicide program by variety interactions for yield parameters. In both years, PM disease severity, characterized by the area under the disease progress curve (AUDPC), was lowest on ‘Camaro’ and highest on ‘Howden’. In 2009, unsprayed ‘Camaro’ had similar AUDPC values as ‘Aladdin’ and ‘Howden’ treated with low- or high-input fungicide programs. In 2010, unsprayed ‘Camaro’ had less disease than ‘Aladdin’ or ‘Howden’ that had received the high-intensity fungicide program. These results suggest that yields can be maintained with a minimal fungicide program when using a variety with high cucurbit PM resistant in some environments. A high-input fungicide program may be necessary to maintain yields of varieties with low cucurbit PM resistance.
Crop Load Management Does Not Consistently Improve Crop Value of ‘Sweetheart’/‘Mazzard’ Sweet Cherry Trees
Authors: Einhorn Todd C. , Laraway Debra , Turner Janet
Published: December 2018

The effect of crop load level on vegetative growth, fruit growth, yield, fruit quality, surface pitting, crop value and return bloom was studied over a 2-year period on 9- and 10-year-old ‘Sweetheart’/‘Mazzard’ sweet cherry (Prunus avium) trees. In early spring, whole-tree crop loads were adjusted to two different levels by removal of reproductive buds (either 50% or all but one) from spurs and compared with an unthinned control. In 2009, heavy crop loads of unthinned trees reduced fruit size by 30 days after full bloom (DAFB). At harvest, fruit diameter of thinned treatments was increased 22% and 27% compared with unthinned fruit. Fruit quality attributes [soluble solids concentration (SS), fruit firmness, and total acids (TA)] were significantly greater for thinned treatments. Thinned treatment yields were reduced 40% to 54% relative to unthinned trees, with greater percentages of fruit in large size classes. Despite significantly fewer fruit per tree, moderately thinned trees had a higher estimated crop value ($142 per tree) than unthinned trees ($125 per tree). Crop value was lowest for the heavily thinned treatment ($107 per tree), reflecting overthinning. In 2010, shoot growth was negatively related to crop load level. Fruit growth of unthinned trees was not significantly affected by higher fruit density until 89 DAFB. Yield of 2010 unthinned trees was 87% of 2009, while thinned tree yields were similar between years. Improved fruit quality and greater percentages of large fruit were observed for thinned treatments in 2010; however, crop value was highest for unthinned trees ($190 per tree), even though 18% of the fruit were too small for fresh market sale. Surface pitting was unaffected by crop load level in either year. Return bloom (flowers per reproductive bud and reproductive buds per spur) was significantly, negatively related to the prior season's crop load in 2010 and 2011. In the current sweet cherry pricing structure, higher crop value is associated with large volumes of medium-sized fruit. Thinning to manage crop load of low-medium density, productive ‘Sweetheart’/‘Mazzard’ trees will not be an annual requirement, though in heavy fruit set years crop load management will improve crop value.
Mugwort Control in an Abandoned Nursery Using Herbicides That Mimic Indole-3-Acetic Acid
Authors: Koepke-Hill Rebecca M. , Armel Gregory R. , Klingeman William E. , Halcomb Mark A. , Vargas Jose J. , Flanagan Phillip C.
Published: December 2018

Field and greenhouse studies were conducted to determine if two indole-3-acetic acid herbicide mimics, aminopyralid and aminocyclopyrachlor-methyl, applied at 70, 140, and 280 g·ha−1 postemergence (POST) would control mugwort (Artemisia vulgaris) in an abandoned nursery. These were compared with the commercial standards picloram at 280 g·ha−1 a.i. and clopyralid at 280 g·ha−1. In the field study, picloram and clopyralid controlled mugwort 75% and 31% by 365 days after treatment (DAT), respectively. In contrast, aminopyralid and aminocyclopyrachlor-methyl applied at 140 g·ha−1 controlled mugwort over 90% by 365 DAT. In the greenhouse study, aminopyralid and aminocyclopyrachlor-methyl applied at 140 g·ha−1 controlled mugwort 92% and 96% respectively, although aminopyralid at 70 g·ha−1 provided better visual control (94%) in comparison with aminocyclopyrachlor-methyl (79%) at 70 g·ha−1. Regardless, following shoot growth removal at 30 DAT, mugwort failed to regrow by 60 DAT following exposures to all rates of both herbicides. On the basis of these studies, aminopyralid and aminocyclopyrachlor-methyl have potential to provide excellent control of mugwort compared with the current standards clopyralid and picloram.
Glyphosate Efficacy, Absorption, and Translocation in Selected Four Weed Species Common to Florida Citrus
Authors: Singh Megh , Sharma Shiv D. , Ramirez Analiza H.M. , Jhala Amit J.
Published: December 2018

Glyphosate is the most widely used herbicide for postemergence weed control in Florida citrus (Citrus spp.). Variation in susceptibility of certain weed species to glyphosate has been observed in last few years. Therefore, understanding the mechanism underlying such phenomenon is required. Experiments were conducted to evaluate differences in tolerance of four weed species to glyphosate by quantifying glyphosate efficacy, the amount of epicuticular wax, absorption, and translocation of carbon-14-labeled glyphosate (14C glyphosate). The results of glyphosate efficacy study suggested that application of glyphosate at 3 oz/acre resulted in 99%, 90%, and 84% control of florida beggarweed (Desmodium tortuosum), spanishneedles (Bidens bipinnata), and johnsongrass (Sorghum halepense), respectively. Increasing application rate and addition of nonionic surfactant (NIS) usually did not improve glyphosate efficacy. Ivyleaf morningglory (Ipomoea hederacea) was the most tolerant and resulted in 0% and 25% control when glyphosate applied at 3 and 24 oz/acre, respectively. Biomass reduction in all weed species reflected a similar trend to percent control in response to all glyphosate treatments. Glyphosate absorption and translocation in the weed species were differed with the quantity of wax extracted. Ivyleaf morningglory had the lowest leaf wax content (10.8 μg·cm−2) and showed less absorption (62% to 79%) and translocation (15% to 39%) of 14C-glyphosate compared with other weed species. The absorption of 14C-glyphosate was in the range of 87%, 71% to 83%, and 72% to 83%; and translocation was 34% to 50%, 32% to 52%, and 53% to 58% in florida beggarweed, spanishneedles, and johnsongrass, respectively. Increasing glyphosate application rate from 6 to 12 oz/acre and addition of NIS usually increased 14C-glyphosate translocation.
Application of the “4R” Nutrient Stewardship Concept to Horticultural Crops: Applying Nutrients at the “Right Time”
Authors: Mattson Neil S. , van Iersel Marc W.
Published: December 2018

The 4R nutrient stewardship framework presents four concepts to consider when applying fertilizers in a responsible matter; the “right source” of nutrients should be applied at the “right rate” during the “right time” and supplied to the “right place” to ensure their uptake. In this article, we provide ideas to consider when attempting to provide nutrients at the right time. When nutrients are applied at a time when they are not required by the plant, the result can be economic and environmental losses. Oversupply relative to plant demand can result in losses of applied nutrients because of leaching or volatilization. Undersupply relative to demand, especially in the case of phloem-immobile nutrients, may limit plant growth and yield. Several factors interact to affect plant nutrient demand such as growth stage, life history (annual vs. perennial), environmental conditions, and plant health. Techniques such as soil and tissue testing, isotopic labeling, and spectral reflectance have been used with varying degrees of success and expense to measure plant nutrient demand and guide fertilizer decisions. Besides knowledge of plant nutrient demand, efficient nutrient supply also depends on systems that allow precise spatial and temporal delivery of nutrients. Future improvements to the timing of nutrient delivery will depend on improvement in knowledge of plant nutrient demands. For example, targeted gene expression chips show promise for use in rapidly assessing plant status for a broad suite of nutrients. Future developments that allow more precise nutrient delivery or more robust agroecosystems that scavenge available nutrients before they are lost to the environment will also help producers use nutrients more efficiently.
Instrumental and Sensory Evaluation of Fruit Quality for ‘Ryan's Sun’ Peach Grown under Deficit Irrigation
Authors: Lopez Gerardo , Behboudian M. Hossein , Echeverria Gemma , Girona Joan , Marsal Jordi
Published: December 2018

The dwindling water supply, on a global scale, is making deficit irrigation (DI) more a necessity than a choice. It is therefore necessary to evaluate the effects of DI on fruit quality. Only instrumental evaluation of quality has been reported in the literature and, to the best of our knowledge, no sensory evaluation has been reported for any DI fruit including peach (Prunus persica). We applied four irrigation treatments for 50 days before harvest to ‘Ryan's Sun’ peach and evaluated fruit quality and sensory attributes. Treatments were: full irrigation (FI), no irrigation (NI), FI followed by NI (FI/NI), and NI followed by FI (NI/FI). NI reduced fruit size, delayed fruit maturity, and increased fruit dry matter concentration (DMC) compared with FI. NI also increased fruit soluble solids concentration (SSC) and titratable acidity (TA). A trained taste panel indicated that NI increased fruit firmness, crispness, and sourness, but it reduced sweetness, juiciness, and the intensity of peach flavor. A panel of consumers indicated reduced preference for NI fruit. Consumer preference was similar between NI/FI and FI fruit but was reduced in FI/NI fruit. There were no significant correlations between the instrumental quality parameters and sensory attributes. We conclude that NI before harvest impaired organoleptic peach quality. If only a small amount of water is available during the 50 days before harvest, peach organoleptic quality could be improved if this water is applied just before harvest.
Vegetative Establishment Rate and Stolon Growth Characteristics of 10 Zoysiagrasses in Southern Europe
Authors: Pompeiano Antonio , Grossi Nicola , Volterrani Marco
Published: December 2018

In today's climate, in which economic and environmental sustainability has to be ensured, it is important to promote the use of grass species that require minimal maintenance inputs. The superior heat and drought tolerance of zoysiagrass (Zoysia spp.) makes it an excellent choice for Mediterranean areas. A study was conducted to evaluate the establishment rate from vegetative plugs of 10 zoysiagrass genotypes (i.e., species and cultivars). Stolon growth rate, establishment rates, biometric traits, and winter color retention were measured. Establishment rate was measured using digital image analysis, and the data were fit to a sigmoid variable slope model. Zoysiagrass genotype significantly affected turf coverage during the establishment. At 140 days after plugging, ‘DALZ0101’ and ‘Zenith’ had significantly more turfgrass coverage, while ‘Emerald’, ‘HT-210’, ‘Meyer’, and mascarene grass (Zoysia pacifica) had the lowest coverage. Differences in total stolon length and growth rate were observed among the genotypes and for all stolon growth parameters. Japanese lawn grass (Zoysia japonica) had higher values compared with manilagrass (Zoysia matrella). A distinct trend in days to maintained 50% color retention (Days50) was observed in this study on the winter color retention of genotypes. Differences in color retention within japanese lawn grass cultivars were observed with ‘Victoria’ retaining color longer than ‘DeAnza’ and ‘El Toro’ (77.6, 57.8, and 57.2 Days50, respectively) and better than ‘Meyer’. Japanese lawn grass cultivars exhibited poor color retention (50.3 Days50) compared with manilagrass cultivars (79.3 Days50).
Methods for Determining Nitrogen Release from Controlled-release Fertilizers Used for Vegetable Production
Authors: Carson Luther C. , Ozores-Hampton Monica
Published: December 2018

The purpose of this article is to review nitrogen (N) controlled-release fertilizer (CRF) research methods used to measure nutrient release from CRFs. If CRF-N release patterns match vegetable crop needs, crop N uptake may become more efficient, thus resulting in similar or greater yields, reduced fertilizer N needs, and reduced environmental N losses. Three methods categories to estimate N release are: laboratory; growth chamber, greenhouse, or both; and field methods. Laboratory methods include a standard and accelerated temperature-controlled incubation methods (TCIMs); methods incubate CRF using selected time periods, temperatures, and/or sampling methods. Accelerated TCIMs, in contrast to the standard method, allow for shorter incubation periods. Growth chamber and greenhouse methods, including column and plastic bag studies, may be used to test new CRF products in conditions similar to particular vegetable production systems. However, the column method predicts N release from CRFs more effectively than the plastic bag method because of ammonia volatilization and lower N recovery rates associated with the bag method. Both field methods, pot-in-pot and pouch methods, are viable vegetable research options. The pouch method measures N remaining in the CRF prill and the pot-in-pot method measures N released from the CRF, thus each method can be applied to different research objectives. Nitrogen released during incubation may be measured using methods such as total Kjeldahl N (TKN), prill weight loss, combustion, colorimetric, or ion-specific electrodes. The prill weight loss method is the least expensive but can only be used with urea CRF. Thus, the CRF-N source(s) and research objectives will determine the appropriate N analysis method. More research needs to be completed on correlations of field and laboratory CRF extractions. Field release methods should be considered the most reliable indicator of CRF-N performance until a laboratory method reliably predicts CRF-N expected field response.
Effect of Sugar-based Compounds in Enhancing the Efficacy of Insecticides against the Western Flower Thrips
Authors: Cloyd Raymond A. , Gillespie Joshua D.
Published: December 2018

It has been proposed by greenhouse producers that adding sugar to a stomach poison insecticide enhances the efficacy of the insecticide in controlling western flower thrips (Frankliniella occidentalis). As such, a series of laboratory, including no-choice and multiple-choice assays, and greenhouse experiments were conducted to determine if adding sugar-based compounds to insecticides enhances efficacy against western flower thrips. The sugar-based compounds evaluated were Mountain Dew, Diet Mountain Dew, white sugar, and brown sugar at two rates [initial (0.18 mL/100 mL and 0.12 g/100 mL) and high (0.36 mL/100 mL and 0.24 g/100 mL)]. A water control was also included in all the assays. In the laboratory experiments, western flower thrips adults and nymphs were not attracted to any of the sugar-based compounds with <60 s (out of 300 s total) spent in any of the treatments, and ≤29 s (out of 300 s total) spent in the treatments when the sugar-based compounds were mixed with three insecticides (tau-fluvalinate, pyridalyl, and spinosad). In the greenhouse experiments, the addition of the high rate of Mountain Dew (0.36 mL/100 mL) and brown sugar (0.24 g/100 mL) did not enhance the efficacy (based on percent mortality) of the insecticides against western flower thrips. There was no significant difference between the individual insecticide treatments and the mixtures with either Mountain Dew or brown sugar. This study is the first to quantitatively demonstrate that western flower thrips adults and nymphs are not attracted to sugar-based compounds and that it is not warranted to add these types of materials to spray solutions targeted for control of western flower thrips.