bluuebunny/crossref_metadata_2025 huggingface dataset:
Canopy Cover and Root-zone Heating Effects on Fall- and Spring-grown Leaf Lettuce Yield in Ohio
Authors: Bumgarner Natalie R. , Bennett Mark A. , Ling Peter P. , Mullen Robert W. , Kleinhenz Matthew D.
Published: December 2018

Low and high tunnels and root-zone heating systems are proven tools in horticultural production. However, impacts of their separate and combined application on crop yield, composition, and microclimates are underreported. We addressed these gaps in the literature by exposing lettuce (Lactuca sativa) to four microclimates established with low and high tunnels and root-zone heating during the spring and fall of 2 years in Wooster, OH. Red-leaved romaine lettuce cultivars Outredgeous and Flagship were direct-seeded into raised beds in both outdoor and high-tunnel settings in early October and late March and harvested multiple times over 4 weeks. Half of all plots in each setting were underlain by electric heating cables, and half were covered with 0.8-mil, clear, vented, low tunnels. A growing medium consisting of peat moss, compost, soil, and red clover (Trifolium pratense) hay was used, and all plots were overhead-irrigated. Soil and air temperatures were monitored throughout the experiments, which were repeated four times (2 seasons/year × 2 years). Here, we report primarily on treatment effects on crop yield and related variables. Root- and shoot-zone conditions and cultivar significantly affected leaf biomass in both settings (outdoor, high tunnel), while population was more often affected in the outdoor experiments. Microclimate main effects were more prevalent than cultivar effects or interactions. Leaf yield was greater in low-tunnel-covered and bottom-heated plots than in uncovered and unheated plots. We take these data as further evidence of the potential to alter lettuce yield through root- and shoot-zone microclimate modification, particularly in regions prone to dynamic seasonal and within-season temperature and light conditions. The data also suggest that the relative performance of low and high tunnels in the production of short-statured, quick-cycling crops during fall and spring be more thoroughly evaluated.
Industry Survey of the Native Wildflower Market in Florida
Authors: Kauth Philip J. , Pérez Hector E.
Published: December 2018

Native plant sales have increased steadily during the past decade because of consumer concern with invasive plant sales, water conservation, and land management issues. However, native plants are still under-used mostly because of a small market and the lack of education on the use and care of native plants. For example, native plant sales in Florida accounted for only 11% of the total horticultural market in 2005. Within the Florida native plant industry, a small, but competitive market focuses on native wildflowers, but a paucity of information related to opportunities within this segment exists. We sent surveys to 137 members of the Florida native plant industry to learn about their interests, concerns, and trends in the native wildflower market. Survey respondents identified low demand, seed supply, and availability of desired species, plus insufficient customer and industry education as major factors limiting Florida native wildflower (FNW) sales. An overwhelming majority predicted that sales for locally produced FNWs would increase over the next 5 years. Respondents also stated that seed germination, seed storage, and seed production research are vital for the advancement of the industry. This survey provides an excellent opportunity to analyze the current native wildflower market and identify areas to help increase awareness of FNWs.
Perceptions of Land-grant University Specialists Regarding Competition and Collaboration with Community College Programs in Viticulture and Enology
Authors: Stafne Eric T. , Kelsey Kathleen D.
Published: December 2018

Junior college (JC) and community college (CC) programs offering viticulture and enology courses have proliferated in recent years in many states, especially outside of traditional grape growing regions. A survey was sent to 69 land-grant (LG) horticulture, viticulture, and enology specialists who may interact with JC and CC programs offering viticulture and enology courses. Forty answered for a response rate of 58%. Results indicated that most LG horticulture/viticulture programs are not interacting with the JC/CC programs and that LG specialists do not believe the education received by students of the JC/CC program is sufficient to create well-trained industry professionals. JC/CC programs are generally regarded as positive for the viticulture and enology industry by LG specialists, but some question the quality of instruction. Many LG respondents do not believe the JC/CC programs are impacting their own programs and do not see the JC/CC programs as competitors to their programs; however, documented actions of JC/CC programs would dictate otherwise, especially in the area of Cooperative Extension programming. LG viticulture and enology programs should no longer consider JC/CC programs as noncompetitors for funding and clientele interaction, especially in states with limited resources. LG programs should seek to develop appropriate partnerships with JC/CC programs to benefit the viticulture and enology community. However, any collaboration must be mutually beneficial, well-designed, well-coordinated, and conducted with reciprocal respect for each program.
The Feasibility of Organic Nutrient Management in Large-scale Sweet Corn Production for Processing
Authors: Johnson Heidi J. , Colquhoun Jed B. , Bussan Alvin J.
Published: December 2018

There is significant interest from vegetable processors, growers, and consumers in organic sweet corn (Zea mays) production. Organic nitrogen (N) management is particularly challenging in high N consuming crops such as sweet corn because of the low N content and low N to phosphorus (P) ratios of organic soil amendments. Various management programs were compared to determine the optimal combination of soil amendments and green manure crops for organic sweet corn production. Alfalfa (Medicago sativa), rye (Secale cereale), and field pea (Pisum sativum) were used as green manure crops. Composted poultry manure and a high N content organic fertilizer were used as organic amendments. Ammonium nitrate was used in a conventional management program for comparison. Treatments were designed to deliver a full rate of N (150 lb/acre), a half rate of N (75 lb/acre), and to limit the amount of P applied. Phosphorus can become a source of pollution when applied to erodible soils, particularly when soils already contain excessive P. Sweet corn yield in many of the organic programs was highly variable among years while the yield was more consistent in the conventional program. This was attributed to differences in organic N mineralization in both the green manure crops and the amendments. The most stable yield from an organic treatment, among years, was achieved using the commercially available organic N fertilizer. Commercially available amendments were costly, and although organic sweet corn received a premium price in years when organic yields were lower, profit was reduced by the high cost of N management.
Estimating Nitrogen Mineralization of Composted Poultry Manure, Organic Fertilizers, and Green Manure Crops for Organic Sweet Corn Production on a Sandy Soil Under Laboratory Conditions
Authors: Johnson Heidi J. , Colquhoun Jed B. , Bussan Alvin J. , Laboski Carrie A.M.
Published: December 2018

Organic sweet corn (Zea mays) production is challenging for growers because of the high nitrogen (N) requirements of sweet corn and the relatively low N content of organic soil amendments. Total N supplied and rate of mineralization throughout the growing season are two important aspects in determining the optimal N management program. Green manure (GrM) crops, composted manures, and commercially available organic fertilizers are used to manage N in organic production systems. Using a combination of these tactics can optimize N while minimizing cost. In this study, we used combinations of composted poultry manure (CPM) and two organic fertilizers (one high N and one with a balance of nutrients) with three GrM crops [rye (Secale cereale), alfalfa (Medicago sativa), and pea (Pisum sativum)] in a loamy sand soil for a 112-day laboratory incubation study. Total plant available N (PAN) was quantified at six times throughout the 16 weeks to determine total N mineralized and rate of N release from each of the management programs. The CPM and the high N organic fertilizer mineralized completely within the first 6 weeks of the study, while only 65% of the other organic fertilizer mineralized by the end of the study. Total N mineralized from pea grown as a GrM for 48 days was comparable to the amount of N mineralized from rye suggesting that pea as a GrM crop should not receive an N credit in field production on a sandy soil. Significant quantities of PAN were mineralized from alfalfa residue, the equivalent of 80 lb/acre, although this is not sufficient for sweet corn production. The combination of alfalfa and the high N organic fertilizer provided sufficient N for sweet corn production and the mineralization rate closely matched sweet corn need. The release of N from CPM, even in combination with GrM crops, was asynchronous with sweet corn crop need.
In-row Diploid Watermelon Pollenizer Competition with Triploid Watermelon Based on Four Planting Ratios
Authors: Adkins Joshua I. , Freeman Joshua H. , Olson Stephen M.
Published: December 2018

Diploid watermelon (Citrullus lanatus) pollenizers are planted within triploid watermelon fields to provide viable pollen for triploid fruit set. In recent years, pollenizer cultivars with desirable characteristics for planting in-row with triploid watermelons have been commercially available. The degree of plant competition from in-row pollenizers grown in the commercially common arrangement where pollenizers are placed equidistant from neighboring triploid plants has not been reported. Field experiments were conducted in 2005, 2006, and 2007 in Quincy, FL, to examine the competitive impact of in-row pollenizers grown equidistant from neighboring triploid plants. Four ratios of pollenizers-to-triploids: 1:1, 1:2, 1:3, and 1:4 were used to provide various levels of pollenizer competition. No significant difference in yield based on the weight or number of fruit per triploid plant resulted from the varied pollenizer ratios. Therefore, pollenizers grown in-row at an equidistant spacing from the neighboring triploid plants had no competitive impact on the yield of the triploid watermelon crop.
Producing a Grafted and a Non-Grafted Tomato Plant from the Same Seedling
Authors: Hanna Hanna Y.
Published: December 2018

Growing grafted hybrid tomato (Solanum lycopersicum) cultivars in greenhouse operations is gaining popularity worldwide. The costs of producing grafted plants remain a deterrent to the smaller producer. After removing plant tops to use as scions for grafting tomato plants, the stumps that have well-developed root systems and cotyledon leaves are usually discarded with the root media and containers. If productive plants can be produced from sprouts on the stumps, they can be used as non-grafted hybrids at the same farm or sold to other growers for income to defray part of the grafting costs. A 2-year greenhouse study examined the effects of three propagation methods and three tomato cultivars on plant yield and related traits. Seedling, grafted, and stump sprout plants of the hybrid cultivars Geronimo, Quest, and Starbuck were used in this study. Plants grafted on ‘Maxifort’ rootstock had greater stem diameter (P < 0.0001) below the first and third clusters than the seedling or stump sprout plants. The seedling plants had greater stem diameter than stump sprout plants below both clusters. During the first 3 weeks of harvest, seedling plants produced greater yields (P < 0.0001) than grafted or stump sprout plants and the differences were cultivar related. ‘Quest’ was the only cultivar that produced similar yields (2.8 vs. 2.3 lb) as a seedling or a grafted plant during the first 3 weeks of harvest. Tomato plants propagated by all three methods produced similar yields and fruit weight in the remaining 16 weeks of harvest. Cultivars had no significant effect on yield during the first 3 weeks of harvest (P > 0.05), but their yields were significantly different during the remaining 16 weeks of harvest (P < 0.0001). The apparent reason for yield advantages of the seedling plants during the first 3 weeks of harvest was the uninterrupted growth during the seedling stage. Propagation method had no specific influence on fruit quality attributes. On the bases of this study, producing productive tomato plants from stump sprouts is a feasible cultural technique that can reduce losses associated with plants used in grafting. It also allows the repeated use of the soilless media and the seedling containers. The produced plants can generate substantial income for businesses that graft a significant number of tomato seedlings. For this cultural method to work, grafting should be timed to allow the stump sprout plants to grow for at least 5 weeks before planting in the grow bags. This practice is normally followed in producing transplants from seeds.
Results from a Mail Survey to Assess Minnesota Vegetable Growers’ Adherence to Good Agricultural Practices
Authors: Hultberg Annalisa , Schermann Michele , Tong Cindy
Published: December 2018

To learn what areas should be emphasized in future educational good agricultural practices (GAPs) training efforts, a survey on usage of GAPs was mailed to 855 vegetable growers in Minnesota. We received a 32% response rate and a 43% cooperation rate. Over 65% of respondents reported compliance to proper worker hygiene practices, harvest container and tool sanitization and cleaning, water treatment to reduce the potential for microbial contamination, and protection of growing and stored vegetables from contamination. Small acreages and a diverse array of vegetables are typical characteristics of the majority of Minnesota vegetable farms. Seventy-seven percent of respondents farmed 15 acres or less. Most farms grew 10 or more different vegetable crops, and farmers markets, u-pick operations, and roadside stands were the most common marketing outlets. Overall responses to this study indicated that farmers currently believe they adhere to many recommended food safety best practices, but are lagging in key areas such as treating wash and processing water, taking measures to keep animals out of production fields, and cleaning and disinfecting harvesting tools and containers on a scheduled basis.
Effects of Species Proportions and Fertility on Sedum Green Roof Modules
Authors: Barker Kristoffer J. , Lubell Jessica D.
Published: December 2018

Nursery producers are interested in supplying sedum (Sedum sp.)-vegetated modular units for the green roof industry. This research examined the influence of three rates of controlled-release fertilizer (CRF) (50, 78, and 108 g per unit of 15N–3.9P–10K, 8- to 9-month formulation) on production of modules containing one or two Sedum species. Six Sedum species were evaluated independently: ‘Angelina’ sedum (Sedum rupestre), gray sedum (S. pachyclados), ‘John Creech’ sedum (S. spurium), tasteless sedum (S. sexangulare), ‘Weihenstephaner's Gold’ sedum (S. kamtschaticum var. floriferum), and white sedum (S. album). The species were then paired as follows: white sedum/‘John Creech’ sedum, ‘Weihenstephaner's Gold’ sedum/‘Angelina’ sedum, and gray sedum/tasteless sedum. For each pair, three starting proportions of cuttings were studied. In 8 weeks, the medium and high fertility rates produced significantly more units with at least 95% vegetation coverage than the low rate. In general, increasing the fertility rate increased the fresh weight at time of harvest, except for ‘Weihenstephaner's Gold’ sedum and tasteless sedum at the high rate, which developed “melt out.” Melted-out tissues turned brown, desiccated and detracted from the visual appearance of units. ‘John Creech’ sedum and white sedum had the greatest fresh weight followed by ‘Weihenstephaner's Gold’ sedum, ‘Angelina’ sedum, and tasteless sedum. Gray sedum grew substantially slower than all other species and had the lowest fresh weight. For white sedum/‘John Creech’ sedum units, harvest fresh weight proportions were similar to starting cutting fresh weight proportions. For gray sedum/tasteless sedum units, tasteless sedum outgrew gray sedum and gray sedum was barely noticeable in finished units. Harvest fresh weight and digital image analysis (DIA) of ‘Weihenstephaner's Gold’ sedum/‘Angelina' sedum units indicated that ‘Weihenstephaner's Gold’ sedum colonized units faster than ‘Angelina’ sedum, and had greater visual impact in finished units. Units started with 25% ‘Weihenstephaner's Gold’ sedum cuttings, the smallest proportion tested, were roughly 73% covered with ‘Weihenstephaner's Gold’ sedum at harvest. We recommend growers use the medium fertility rate to produce the most units with 95% vegetation or more in the least amount of time and with reduced risk of melt out. To achieve desired final species proportions, growers may need to adjust the ratios of cuttings based on uneven species vigor.
A Mobile Platform for Measuring Canopy Photosynthetically Active Radiation Interception in Orchard Systems
Authors: Lampinen Bruce D. , Udompetaikul Vasu , Browne Gregory T. , Metcalf Samuel G. , Stewart William L. , Contador Loreto , Negrón Claudia , Upadhyaya Shrini K.
Published: December 2018

A mobile platform was developed for measuring midday canopy photosynthetically active radiation (PAR) interception in orchards. The results presented are for almond (Prunus dulcis) and walnut (Juglans regia), but the mobile platform can be used in other orchard crops as well. The mobile platform is adjustable to accommodate orchard row spacing from 4.8 to 7.8 m and is equipped with a global positioning satellite (GPS) receiver and radar for positional assessment as well as three IR thermometers for measuring soil surface temperature. Data from the mobile platform are logged at 10 Hz and stored on a data logger. Custom software has been developed to process the data. The mobile platform was used extensively for mapping midday canopy PAR interception in almond and walnut orchards in 2009 and 2010. The mobile platform produced comparable results to those collected with a handheld light bar with the advantage of being able to cover much larger areas and compare these data to mechanically harvested yield data over the same area. For almond orchards, midday canopy PAR interception peaked at ≈70% at an orchard age of ≈12 years. For walnut orchards, midday canopy PAR interception continued to increase to ≈15 years of age and peaked at a level above 80%. The mobile platform was also able to follow seasonal development of midday canopy PAR interception in young and mature orchards. This technology has potential for evaluating new varieties in terms of productivity per unit PAR intercepted, in evaluating hand pruning or mechanical hedging practices in terms of impact on PAR interception/productivity as well as evaluating effectiveness of insect or disease management treatments. It also has potential as a reference point for grower self-assessment to evaluate orchard canopy development compared with other orchards of similar variety, spacing, etc. Finally, this technology could be used as ground truth referencing for remotely sensed data.
Yield and Fruit Quality Traits of Mamey Sapote Cultivars Grown at Two Locations in Puerto Rico
Authors: Goenaga Ricardo , Jenkins David
Published: December 2018

The demand for tropical fruits has increased significantly during the last decade as consumers seek healthy and more diverse food products. There is a lack of formal experimentation to determine yield performance and fruit quality traits of mamey sapote (Pouteria sapota) cultivars. Six mamey sapote cultivars (Copan, Magaña, Mayapan, Pace, Pantin, Tazumal) grown on Ultisol and 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 25,929 fruit/ha and 16,527 kg·ha−1 at Corozal and 17,887 fruit/ha and 11,920 kg·ha−1 at Isabela. ‘Tazumal’ had the highest 5-year mean number and weight of fruit per hectare, but fruit of this cultivar was very small and contained several seeds, which could reduce its marketability. At Corozal, cultivars Tazumal and Magaña had significantly higher fruit yield per hectare than the rest of the cultivars, whereas ‘Magaña’, ‘Tazumal’, and ‘Pantín’ had the highest fruit yield at Isabela. At both locations, ‘Pantin’ had relatively high yield, above-average soluble solids concentration values, and adequate fruit size and weight for domestic and export markets (650–900 g), making this cultivar suitable for planting at various agroenvironments typical of the humid tropics.
Dry Storage Effects on Postharvest Performance of Selected Cut Flowers
Authors: Ahmad Iftikhar , Dole John M. , Amjad Atyab , Ahmad Sagheer
Published: December 2018

Effects of wet and dry storage methods were compared to improve postharvest performance of specialty cut flower species. While increasing duration of storage reduced vase life, vase life declined less with dry storage for marigold (Tagetes erecta) and rose (Rosa hybrida), but not for zinnia (Zinnia elegans) or lisianthus (Eustoma grandiflorum) over wet storage. Marigold stems had 1.9, 4.6, and 1.5 days longer vase life after 1, 2, or 3 weeks in dry storage, respectively, as compared with storage in water. Zinnia stems did not tolerate either wet or dry storage, while lisianthus stems had a longer vase life when stored in water as compared with dry storage. For rose, dry storage for 2 weeks increased vase life compared with wet storage. Dry stored marigold and lisianthus stems had higher water uptake after being placed in the vase as compared with the stems stored in water, while zinnia and rose had less uptake. Storage method had no effect on leaf relative water content (LRWC) in lisianthus, marigold, and zinnia; however, LRWC decreased with increased storage duration. This necessitates evaluation of storage method and duration effects for each species and cultivar to ensure extended storage life and improve postharvest quality.
Nutrient Disorders of ‘Evolution’ Mealy-cup Sage
Authors: Barnes Jared , Whipker Brian , McCall Ingram , Frantz Jonathan
Published: December 2018

To produce floriculture crops like mealy-cup sage (Salvia farinacea), growers must be equipped with cultural information including the ability to recognize and characterize nutrient disorders. ‘Evolution’ mealy-cup sage plants were grown in silica-sand culture to induce, describe, and photograph symptoms of nutritional disorders. Plants received a complete modified Hoagland's all-nitrate solution of (macronutrient concentrations in millimoles) 15 nitrate-nitrogen (N), 1.0 phosphorus (P), 6.0 potassium (K), 5.0 calcium (Ca), 2.0 magnesium (Mg), and 2.0 sulfur (S) plus (micronutrient concentrations in micromoles) 72 iron (Fe), 18 manganese (Mn), 3 copper (Cu), 3 zinc (Zn), 45 boron (B), and 0.1 molybdenum (Mo). Nutrient-deficient treatments were induced with a complete nutrient formula minus one of the nutrients. The B-toxicity treatment was induced by increasing the element 10-fold higher than the complete nutrient formula. Reagent-grade chemicals and deionized (DI) water of 18 million ohms per centimeter purity were used to formulate treatment solutions. We monitored plants daily to document and photograph sequential series of symptoms as they developed. Typical symptomology of nutrient disorders and corresponding tissue concentrations were determined. Out of 13 treatments, 12 exhibited symptomology; Mo was asymptomatic. Symptoms of N, P, S, Ca, and K deficiencies and B toxicity manifested early; therefore, these disorders may be more likely problems encountered by growers. Unique symptoms were observed on plants grown under N-, Cu-, and Zn-deficient conditions. Necrosis was a common symptom observed, but use of other diagnostic criteria about location on the plant and progression of the disorder can aid growers in diagnosing nutrient disorders of mealy-cup sage.
‘Trinidad Moruga Scorpion’ Pepper is the World’s Hottest Measured Chile Pepper at More Than Two Million Scoville Heat Units
Authors: Bosland Paul W. , Coon Danise , Reeves Gregory
Published: December 2018

This study established the heat levels for several high-heat chile pepper (Capsicum chinense) varieties (Trinidad Moruga Scorpion, Bhut Jolokia, Trinidad Scorpion, Douglah Trinidad Chocolate, and Trinidad 7-pot Jonah) to determine which variety has the highest average measured heat level and the relatedness of the chile peppers using molecular analysis. In replicated trials with appropriate controls at Las Cruces, NM, results show two ‘Trinidad Moruga Scorpion’ chile pepper plants reached more than two million Scoville heat units (SHU). This is the first confirmation of chile pepper fruit measuring more than two million SHU. A large range of heat levels was observed among the field plots—further supporting strong environmental effects on chile pepper pungency. ‘Trinidad Moruga Scorpion’ was significantly hotter than ‘Bhut Jolokia’, but ‘Trinidad 7-pot Jonah’, ‘Douglah Trinidad Chocolate’, and ‘Trinidad Scorpion’ did not differ significantly from ‘Bhut Jolokia’. Molecular analysis with randomly amplified polymorphic DNA (RAPD) markers confirmed that the accessions are genetically unique. ‘Trinidad Moruga Scorpion’ belongs to the species C. chinense and is not the same chile pepper as ‘Bhut Jolokia’.
Does FreezePruf Topical Spray Increase Plant Resistance to Freezing Stress?
Authors: Anderson Jeff A.
Published: December 2018

One method of plant freeze protection involves the application of compounds that promote freeze avoidance or tolerance. FreezePruf, a commercially available product recently marketed to improve both freeze avoidance and tolerance, contains polyethylene glycol, potassium silicate, glycerol, silicone polyether surfactant, and a bicyclic oxazolidine antidessicant. The goal of the present study was to evaluate the protection level provided by FreezePruf using laboratory-based methods involving plants and plant parts from species capable and incapable of low-temperature acclimation. FreezePruf did not lower the freezing temperature of pepper (Capsicum annuum) seedlings, celosia (Celosia argentea) seedlings, detached tomato (Solanum lycopersicum) leaves, or postharvest tomato fruit. Spray application of the putative cryoprotectant did not increase the freeze tolerance of bermudagrass (Cynodon dactylon) crowns or stolons. It is possible that a greater level of protection could be achieved with other species or different experimental protocols.
Digital Image Analysis to Supplement Direct Measures of Lettuce Biomass
Authors: Bumgarner Natalie R. , Miller Whitney S. , Kleinhenz Matthew D.
Published: December 2018

Plant growth and biomass assessments are required in production and research. Such assessments are followed by major decisions (e.g., harvest timing) that channel resources and influence outcomes. In research, resources required to assess crop status affect other aspects of experimentation and, therefore, discovery. Destructive harvests are important because they influence treatment selection, replicate number and size, and the opportunity for true repeated measures. This work sought to establish the limits to which image acquisition and analysis may replace standard, destructive measures of fresh lettuce biomass. Outdoor, high tunnel, and greenhouse plantings of three cultivars of red and green leaf lettuce (Lactuca sativa) were direct-seeded in raised beds and plastic trays in spring, summer, and fall seasons in 2009–10 in Wooster, OH. Overhead images (624 in total) were captured at specific time points after seeding using handheld and tripod-mounted commercial digital cameras. Fresh weight and leaf area of destructive plant samples within the digital images were also collected. Images were analyzed using user-defined settings in WinCAM software (Regent Instruments, Quebec, QC, Canada). A reference grid captured within each image allowed for the calculation of crop canopy cover (percent of two-dimensional image area covered by leaves). Calculations of canopy cover require differentiating leaves and rooting medium by color. The rooting medium was dark in color, and differentiating red leaves against this background was less reliable than differentiating green leaves from background. Nevertheless, in samples collected in the greenhouse 7 to 16 days after sowing (DAS), significant correlations (r) of 0.85 to 0.96 (P < 0.05) were observed between measures of canopy cover calculated by image analysis software and leaf area obtained with a leaf area meter on harvested plant material. In outdoor and high tunnel plots 16 to 30 DAS, correlation coefficients between direct measures of plant biomass and WinCAM estimates of canopy cover were 0.71 to 0.95 (P < 0.0001). We conclude that digital image analysis may be useful in real-time, nondestructive assessments of early stage leaf lettuce canopy development, particularly when the leaf area index (LAI) is less than one and settings are dominated by green leaves.
Industry Involvement in the Creation and Funding of the eXtension Grape Community of Practice
Authors: Stafne Eric T. , Hellman Edward W. , Striegler R. Keith , Wolpert James A. , Peltier Jean-Mari
Published: December 2018

Industry involvement is a critical aspect of the Specialty Crops Research Initiative (SCRI). Both a mandate for need and funding are necessary from industry to develop a successful SCRI project. The National Grape and Wine Initiative (NGWI), a nationwide coalition representing all segments of the grape (Vitis sp.) industry including raisin, juice, fresh grape and wine interests, identified extension education as a critical need and charged its extension/outreach committee to concentrate on ensuring industry members are aware of and have access to findings from grape and grape products research. To achieve this goal, the committee decided that a comprehensive online information and educational resource would play an important role. In 2009, the eXtension Grape Community of Practice (GCoP) was funded by the SCRI. The NGWI was active in soliciting letters of endorsement and buy-in from the industry for the project. The Missouri Wine and Grape Board (MWGB) also contributed $20,000 per year for three years to help offset the matching requirement. Research-based grape proposals in subsequent rounds of the SCRI in 2010 and 2011 wishing to have the approval of NGWI have been strongly encouraged to include the GCoP as a portion of their extension component. For the 2011 round of SCRI proposals, this led to the GCoP being included in three projects, two of which were funded. Exploration of future avenues for funding will include subcontracts from other grant awards, NGWI, industry sponsorships, and other creative methods.
eOrganic: The Organic Agriculture Community of Practice for eXtension
Authors: Stone Alexandra G. , Treadwell Danielle D. , Formiga Alice K. , McQueen John P.G. , Wander Michelle M. , Riddle James , Darby Heather M. , Heleba Debra
Published: December 2018

eOrganic is the organic agriculture community of practice (CoP) and resource area for eXtension. eOrganic’s primary community of interest (CoI) is organic farmers and the agricultural professionals who support them. The 250 members of the eOrganic CoP include farmers, researchers, certifiers, and extension/other agricultural professionals. eOrganic’s mission is to build a diverse national CoP and use web technologies to synthesize existing information, emerging science, and practical knowledge into information resources and training materials for its CoI. eOrganic strategies to achieve that mission include collaborative publication, stakeholder engagement, community development, project management, evaluation, and fundraising. eOrganic’s public site currently offers 240 articles, 250 videos, 80 webinars and broadcasts, and 100 frequently asked questions (FAQs). eOrganic CoP members have answered more than 1000 “Ask an Expert” questions. eOrganic authors collaboratively develop articles in eOrganic’s collaborative workspace, which undergo review by two anonymous reviewers and National Organic Program (NOP) compliance review. eOrganic will offer online courses in 2012. eOrganic stakeholders evaluated eOrganic articles and videos in 2010 and overall they stated that they were relevant, science-based, and useful. Three quarters of webinar and broadcast participants said the webinar improved their understanding of the topic, and 83% said they would recommend the webinar to others. Sixty-nine percent of webinar survey respondents stated that they changed practices or provided others with information as the result of the webinar. eOrganic surveyed active CoP members in 2011. Members view eOrganic as important because it is the only national organic agriculture resource with direct ties to university research and they considered all of eOrganic’s core activities important. eOrganic is supported by small grants from eXtension and subawards in more than 20 U.S. Department of Agriculture (USDA), National Institute of Food and Agriculture (NIFA) research/extension projects. To enhance its financial sustainability, eOrganic will work to solidify its partnership with NIFA programs and diversify its funding sources to include course fees and underwriters.
Evolution of Conservation Tillage Systems for Processing Tomato in California’s Central Valley
Authors: Mitchell Jeffrey P. , Klonsky Karen M. , Miyao Eugene M. , Aegerter Brenna J. , Shrestha Anil , Munk Daniel S. , Hembree Kurt , Madden Nicholaus M. , Turini Thomas A.
Published: December 2018

Traditional processing tomato (Solanum lycopersicum) production in California’s Central Valley relies heavily on tillage to produce high yields. However, recent research and farm innovation have produced a variety of conservation tillage (CT) management alternatives that cut costs, reduce soil disturbance, and produce fewer emissions. A 12-year study in Five Points, CA, demonstrated that CT methods reduced tractor passes by 40%, lowered tillage costs by ≈$80 per acre in 2011 dollars, and achieved comparable yields as standard tillage (ST) methods. As comparable yield performance and net profitability are further demonstrated, an array of CT systems will become increasingly attractive to producers and more common in Central Valley tomato growing areas.
Seedling Centipedegrass Response to Mesotrione Plus Simazine Mixtures
Authors: McElroy J. Scott , McCurdy James D. , Flessner Michael L.
Published: December 2018

Centipedegrass (Eremochloa ophiuroides) is a low-maintenance, warm-season grass common throughout the southern United States. Slow establishment and growth rate of seeded centipedegrass often allows for increased weed competition, yet weed control options are limited. Tank-mixing simazine with mesotrione has been reported to improve weed control because of synergistic modes of action. A 2-year field trial was conducted to evaluate centipedegrass response to mesotrione and simazine applications applied 2 weeks after emergence. Mesotrione (0.25 lb/acre) did not reduce centipedegrass cover at any rating when applied alone. All rates of simazine, alone and tank-mixed with mesotrione, resulted in decreased centipedegrass cover 7 days after treatment (DAT). However, simazine alone at 0.25 lb/acre did not reduce turf cover 14, 28, and 49 DAT, and simazine at 0.25 lb/acre tank-mixed with mesotrione at 0.25 lb/acre did not reduce turf cover 28 and 49 DAT. Results indicate that newly established centipedegrass is vulnerable to cover reduction because of simazine and simazine plus mesotrione tank-mixture. Mesotrione and mesotrione tank-mixed with low rates of simazine is a viable option for newly seeded centipedegrass weed control; however, turf cover may be delayed.
The Effect of Tree Cover and Vegetation on Incidence of Childhood Asthma in Metropolitan Statistical Areas of Texas
Authors: Pilat Monica Ann , McFarland Amy , Snelgrove Amy , Collins Kevin , Waliczek Tina Marie , Zajicek Jayne
Published: December 2018

The number of asthma cases in children has increased significantly in the last couple of decades. Studies on links between outdoor air pollutants and asthma have had mixed results, suggesting the need for more focused studies. An increase in tree plantings for urban areas is now being called upon as a solution to the higher heat indexes and pollution rates for more densely populated areas. Green spaces and trees could further benefit some urban areas by providing an effective means to improve air conditions. The purpose of this study was to assess whether there is a relationship between levels of vegetation and reported rates of childhood asthma in Texas. Childhood asthma data were collected from the Center for Health Statistics and the Texas Department of State Health Services for the years 2005 and 2006. The asthma rates for each metropolitan statistical area (MSA) were mapped and inserted into a corresponding vegetation map using geographical mapping software. A comparison of vegetation rates and asthma rates in metropolitan areas was used to investigate whether vegetation and tree cover led to higher or lower incidences of childhood asthma rates. Asthma data, normalized difference vegetation index (NDVI), and canopy cover data were analyzed using statistical software. Regression analysis and correlations were calculated to analyze the data for the tree coverage/vegetation rates and asthma rates variable. No statistically significant relationships between NDVI, canopy cover, and asthma were found in this study.
Rimsulfuron Tank Mixed with Flumioxazin, Pendimethalin, or Oryzalin for Control of Broadleaf Weeds in Citrus
Authors: Jhala Amit J. , Ramirez Analiza H.M. , Singh Megh
Published: December 2018

Herbicides are usually applied multiple times by growers for season long weed control in Florida citrus (Citrus sp.). Rimsulfuron, a sulfonylurea herbicide has been recently registered for control of certain grasses and broadleaf weeds in citrus. To increase the weed control spectrum and reduce application cost, citrus growers often prefer to tank mix herbicides. Field experiments were conducted in 2010 and 2011 in citrus groves in central Florida to evaluate weed control efficacy and crop safety of rimsulfuron applied alone or in tank mixes with flumioxazin, pendimethalin, or oryzalin. Herbicides were applied sequentially in spring and fall in both years on the same experimental plot. Results suggested that rimsulfuron applied alone controlled >80% broadleaf and grass weeds up to 30 days after treatment (DAT) and was comparable to tank mixing rimsulfuron with pendimethalin or oryzalin; however, control was reduced beyond 30 DAT. Rimsulfuron tank mixed with flumioxazin was the most effective treatment at 30 and 60 DAT that provided, respectively, ≥88% and >75%, control of broadleaf weeds including brazil pusley (Richardia brasiliensis), dog fennel (Eupatorium capillifolium), common ragweed (Ambrosia artemisiifolia), cotton weed (Froelichia floridana), and virginia pepperweed (Virginia virginicum) compared with other treatments. Control of natalgrass (Melinis repens) was higher in all tank mix treatments compared with rimsulfuron applied alone with no difference among tank mix partners. Rimsulfuron tank mixed with pendimethalin or oryzalin had no advantage over rimsulfuron applied alone for control of broadleaf weeds. Among sequential applications, weed control was better after fall herbicide application (August) compared with spring (April) because of residual activity of fall applied herbicides. Rimsulfuron tank mixed with flumioxazin will provide citrus growers with an additional weed control option.
Exotic Plant Inventory, Landscape Survey, and Invasiveness Assessment: Roosevelt-Vanderbilt National Historic Sites, Hyde Park, NY
Authors: Bravo Melissa , DiTommaso Antonio , Hayes David
Published: December 2018

An exotic plant cultural landscape inventory, area wide survey, and natural resource area invasiveness assessment was conducted in 2002 at the Roosevelt-Vanderbilt (ROVA) National Historic Sites (NHS) in Hyde Park, NY. At the species level, 40% of 90 assessed landscape species had not escaped cultivation, 44% had escaped and invaded natural resource areas, and 16% were categorized as migratory invaders. The most prolific introduced woody trees and vines at ROVA are members of the trumpetvine, bittersweet, pea, buckthorn, quassia, and grape families (Bignoniaceae, Celastraceae, Fabaceae, Rhamnaceae, Simaroubaceae, and Vitaceae, respectively). Shrub species occurring with more frequency in the natural areas than other escapes are the introduced native atlantic nine bark (Physocarpus opulifolius), burning bush (Euonymus alatus), forsythia (Forsythia sp.), japanese barberry (Berberis thunbergii), morrow’s honeysuckle (Lonicera morrowii), tatarian honeysuckle (Lonicera tatarica), and mock orange (Philadelphus sp.). For the subset of assessed woody vines, shrubs, and tree species found in cultivation for at least 50 to 67 years (the “50 plus club species”), slightly more had escaped from cultivation for the Vanderbilt Mansion (VAMA) and Eleanor Roosevelt (ELRO) estates but for the Franklin Delano Roosevelt (FDR) collection the numbers were equivalent. The approach used in this study illustrates with data the “movement” of exotics over a significant period of time and underscores the importance of site-specific and species-specific assessments. This assessment also emphasizes the value of understanding the history (e.g., cultivated, cultivated escaped, or migratory invaders), purpose (e.g., aquatic, crop garden forb, groundcover, ornamental, or weed), and management over time (e.g., long since abandoned, recently abandoned, or still maintained, etc.) of the geographic area under consideration and the use of available exotic invasive plant lists to conduct such assessments.
Staminate Flower Production and Fusarium Wilt Reaction of Diploid Cultivars Used as Pollenizers for Triploid Watermelon
Authors: Gunter Chris , Egel Daniel S.
Published: December 2018

Several cultivars of nonharvested watermelon (Citrullus lanatus) pollenizers were compared for staminate flower production in field tests and disease reaction to fusarium wilt [Fusarium oxysporum f. sp. Niveum (FON)] in both greenhouse and field tests. Differences were observed in staminate flower counts and fusarium wilt reactions in both years of field evaluations and to fusarium wilt among cultivars evaluated in the greenhouse. ‘SP-1’, ‘Sidekick’, and ‘5WDL 6146’ were the cultivars with high staminate flower counts in the field both years. These cultivars also were among the most resistant to fusarium wilt in both years of field tests. Significant correlations occurred between the rankings of the cultivar’s fusarium wilt reactions in both the two field and three greenhouse experiments, indicating a high degree of correlation between field and greenhouse tests.
Innovative Use of Locally Produced Inputs to Improve Plant Growth, Crop Quality, and Grower Profitability in Hawai’i
Authors: Radovich Theodore J.K. , Pant Archana , Gurr Ian , Hue Ngyuen V. , Sugano Jari , Sipes Brent , Arancon Norman , Tamaru Clyde , Fox Bradley K. , Kobayashi Kent D. , Paull Robert
Published: December 2018

Reducing grower reliance on off-island inputs to promote plant nutrition was identified by industry as a high priority in efforts to improve agricultural sustainability in Hawai’i. A variety of knowledge gaps exist that prevent producers from using locally produced amendments in the fertility program. This study will focus on recent transdisciplinary efforts at the University of Hawai’i to improve understanding of factors that affect variability in the quality, application, efficacy, and cost-effectiveness of locally produced composts, vermicomposts, rendered animal products, and algae in Hawai’i. A series of greenhouse, experiment station, and on-farm trials have supported several conclusions, including 1) aqueous extracts of vermicomposts and high-quality, farmer-produced thermophilic composts can effectively improve crop growth and reduce costs associated with the use of these inputs; 2) replacement of peat and other imports with local materials in vegetable seedling production have the potential to improve seedling vigor and reduce costs in the long term; 3) commercially produced rendered meat products, alone and in combination with commercial composts, are a valuable local source of nitrogen (N); and 4) invasive algae from coral reef remediation may provide a significant source of potassium (K) in the near term, but K content of algae is highly dependent on species and location of growth.
Biomass Yield and Dry Matter Partitioning in Greenhouse-grown Stinging Nettle under Different Fertilization Regimes
Authors: Rutto Laban K. , Ansari Myong-Sook , Brandt Michael
Published: December 2018

Stinging nettle (Urtica dioica) is a specialty crop with economic potential. Apart from being harvested and consumed as a leafy vegetable, stinging nettle has well-documented applications in alternative medicine and industry. However, research on stinging nettle mineral nutrition is insufficient and the current study is part of efforts to establish agronomic guidelines for managed cultivation. Greenhouse experiments were conducted over two seasons (summer and fall) to evaluate stinging nettle growth and dry matter partitioning in response to variations in the supply of nitrogen (N), and N in combination with potassium (K). In the first experiment, seedlings were transplanted into potted media amended with N applied at rates equivalent to 0, 15, 30, 45, 60, and 75 g·m−2, while Expt. 2 consisted of N (15, 45, and 75 g·m−2 equivalent) and K (4, 8, and 12 g·m−2 equivalent) applied in factorial combinations. In Expt. 1, stinging nettle growth was positively correlated with N supply up to 60 g·m−2 during the reproductive phase (summer) and 75 g·m−2 during the vegetative phase (fall), while there was a slight decline in growth and dry matter yield at the highest level of K (12 g·m−2) at all N levels in Expt. 2. In both experiments, growth and dry matter accumulation was higher in the fall than in summer, and high N accounted for significantly more vegetative growth with a concomitant increase in aboveground biomass. Our results suggest that K should be applied at a rate below the growth-limiting threshold of 12 g·m−2. In this study, N strongly stimulated aboveground growth suggesting it is the most important element in stinging nettle nutrition.