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Warm-season Turfgrasses Irrigated with Herbicide-treated Water

Many waterbodies are multi-purpose, and herbicides often are used to manage weeds in these systems. Restrictions limiting irrigation with herbicide-treated water are included on herbicide labels, but lists of affected species are not comprehensive. Haller et al. (p. 599) irrigated three warm-season turfgrasses with water containing aquatic herbicides and found that biomass was reduced by 10% after irrigation with topramezone concentrations lower than the rate used for aquatic weed control. Bispyribac-sodium was less phytotoxic, and only ‘Pensacola’ bahiagrass was affected at aquatic weed control use rates. These results support label instructions and highlight the need to comply with irrigation restrictions.

Flower Color and Longevity of Elepidote Red Rhododendron

Elepidote (large leaved) red rhododendrons with good cold hardiness and true red flower color are not abundant in the landscape trade. Lubell and Brand (p. 607) evaluated the longevity and quality of red flower color on eight cold-hardy elepidote rhododendrons. For flower hue, varieties fell into two groups; either red or bluish red. Where red flower is desired, one can choose among ‘Burma’, Firestorm’, ‘Francesca’, and ‘Henry’s Red’. Flower longevity varied from 10 to 14 days with ‘Francesca’ lasting longest. As flowers aged, their color became bluer and sometimes lighter. ‘Francesca’ flowers exhibited the least change in color as they aged.

Market Value of a Specialty Cut Sunflower Variety

Primarily one type of sunflower is offered as a cut flower in the florist trade. Short et al. (p. 611) found that florists and consumers were receptive to purchasing an alternate-type specialty sunflower variety, Firecracker, and were willing to pay similar prices to those that they are currently paying for standard, commercially grown, imported cut sunflowers. Females were more likely to purchase specialty sunflowers, and individuals who were interested in locally grown products were willing to pay more for the product. Therefore, ‘Firecracker’ has potential product for niche markets.

Using Oil and Soap Against Scale Insects

The efficacy of horticultural oil and insecticidal soap against scale insects might be explained by differences between their integuments. Quesada and Sadof (p. 618) found that both insecticides killed armored and soft scale during crawler stage. However after they settled, horticultural oil killed a greater percentage of armored scales than soft scales, whereas insecticidal soap gave greater control against soft scales. The waxy cover of armored scales might facilitate penetration of lipophilic horticultural oil, whereas aqueous material in the soft scale integuments might facilitate the penetration of polar insecticidal soap.

Container-grown Confetti Trees Irrigated with Runoff Water

Confetti tree is a Mediterranean species widely grown for its ability to adapt to abiotic stresses. García-Caparrós et al. (p. 625) grew confetti trees for 8 weeks in plastic containers with a sphagnum peat moss and perlite substrate (80:20 by volume) and irrigated them with three different irrigation treatments (standard nutrient solution, runoff water blended 50:50 with tap water, and 100% runoffwater). They report that irrigation treatments changed the growth, chlorophyll concentration, and the mineral composition of roots and leaves.

Performance of Hazelnut Varieties in Northeastern Spain

In a comparative trial of 11 hazelnut varieties carried out over 15 years in Tarragona, Spain, Rovira et al. (p. 631) identified varieties with promising agronomic characteristics and industrial value among Italian and Spanish varieties and releases from Oregon State University’s breeding program. However, at the end of the study, they concluded that varieties from Oregon exhibited good performance, but did not show improvement over traditional Mediterranean varieties.

New Fertilizer Coatings/Blends for Nursery Crops

Controlled-release fertilizers (CRF) continue to be a valued tool for nursery growers in producing healthy and profitable crops. Coating technologies and nutrient blends have continued to advance over the years. Grable et al. (p. 639) compared the nutrient release rates of four CRF blends for 8 to 9-month release with currently available and experimental coatings and growth response of ‘Double Play Pink’ japanese spirea and ‘Smaragd’ arbovitae. New polymer coating technologies show promise for delivering a predicted release rate and are appropriate for container production of these woody shrubs in Kentucky.

Tissue Culture Protocols for Conserving Oak Species

Oaks are economically and ecologically valuable around the world, but many species are under threat. Oak secies cannot be preserved through conventional seed banking methods. Tissue culture using mature plant material is an important tool for conservation of oaks, but well-tested and effective protocols are lacking. Brennan et al. (p. 644) evaluated 12 oak species across three taxonomic sections and on two different media. Survival, growth, and contamination varied significantly by species, but not section. Explants on Woody Plant Medium had more growth and longer survival than those on Gresshoff and Doy medium.

Sampling Biodegradable Mulch in Field Soil

Soil sampling with a soil core (6 by 4 inches) has been used to assess the amount of visible biodegradable mulch (BDM) fragments remaining in field post soil-incorporation. However, Ghimire et al. (p. 650) showed that such sampling method recovered less than 70% of the mulch present in the field, and there was high variability between plots. Even 50 samples per plot did not provide an accurate estimate of the amount of mulch remaining in the field. Thus, soil sampling with a large core is unreliable, and new sampling methods are needed.

Citrus Greening Effects Water Use of Young Citrus Trees

Water use of citrus trees has been well-documented; however, the effect of greening [Huanglongbing (HLB)] on water use has not been determined. Hamido et al. (p. 659) studied the effect of HLB on water use of two sweet orange varieties (Hamlin and Valencia) in the greenhouse. Six HLB-affected and six non-affected trees of each variety were grown for 2 years using 12 lysimeters for each variety. Results indicated a greater reduction in water use for affected trees when compared to non-affected trees. Thus, reducing the water supply for HLB-affected trees than healthy trees may result in significant water savings.

Grapefruit Cultivation under Protective Screen

Completely enclosed screen houses can physically exclude contact between young, healthy citrus trees and asian citrus psyllids, and thereby prevent Huanglongbing (HLB) disease. Ferrarezi et al. (p. 666) investigated the impact of anti-psyllid screen houses on growth and physiological parameters of young ‘Ray Ruby’ grapefruit trees. Trees growing inside screen houses developed a larger canopy surface area and leaf area index, and demonstrated increased water use efficiency and leaf water transpiration compared to open-air plantings. The screen houses provided a better growing environment for grapefruit, as protective structures accelerated young tree growth while protecting trees from HLB infection.

Weather Inside Protective Screen Used for Grapefruit Cultivation

Huanglongbing (HLB) disease is transmitted by the vector asian citrus psyllid (ACP). Anti-psyllid screen houses can eliminate HLB development in young citrus plantings by excluding the insect vector. Ferrarezi et al. (p. 675) evaluated the effect of screen houses on excluding infective ACP from inoculating grapefruit trees and determined changes on environmental conditions caused by the screen cloth. ACP and HLB-positive trees were not found inside the screen houses. The screen reduced solar radiation, maximum wind gust, and reference evapotranspiration, and increased air temperature. The environmental conditions inside the protective screen houses were suitable for grapefruit production.

Turfgrass Conversion with Steaming and Flaming

Warm-season turfgrasses are more suited to a Mediterranean climate than common cool-season species. Transplanting in untilled soil can be used to convert from cool-season to warm-season species; however, it requires desiccation of the cool-season turfgrass. Fontanelli et al. (p. 682) compared flaming, steaming, and herbicide application to desiccate tall fescue and perennial ryegrass for conversion to hybrid bermudagrass in untilled soil via transplanting. The highest doses of steaming and flaming almost completely desiccated cool-season turf. Similar hybrid bermudagrass cover (50% to 60%) was established by these two methods and by application of herbicide.

Finding Tasty, High-yield Cacao Varieties Just Got Easier

A 70% cacao, dark chocolate bar uses almost five times more cacao beans than same size 15% cacao, milk chocolate bar. Great-tasting dark chocolate demands higher yields and higher-quality cacao varieties. Shifting Hawaii’s new cacao to chocolate industry from random open-pollinated seedlings to grafted varieties means evaluating yield and taste from locations on many islands. Bittenbender et al. (p. 690) developed a microfermentation method to accurately evaluate taste related to genetics and terroir, and tropical hobbyists can use it too.

Oregon Ag Workers Give Hybrid Education a Try

Uribe and Santamaria (p. 695) designed a hybrid course for pesticide training in Spanish and delivered it over 4 weeks to Oregon nursery and landscape workers. Their goal was to assess the reception of hybrid teaching methods. Growing demand for appropriate training opportunities for Oregon’s increasingly scarce agricultural workers continues to outpace extension’s available time and resources. New, more-efficient, innovative ways of reaching this audience must be explored in order to better fill the need and demand. The hybrid delivery method was very well received, and students showed interest in taking more courses offered in hybrid format.

Hands-on Motivation of Non-majors to Take Plant Science Courses

Many university agriculture programs, including horticulture, are experiencing a decline in enrollments. One strategy to counteract this trend is to attract non-majors to plant science courses. Pritts (p. 704) developed a course almost exclusively based on hands-on activities directed to freshmen, sophomores, and juniors who are not plant science or agricultural science majors. Over the past 3 years, 43% of students who took Hands-On Horticulture enrolled in a subsequent plant science course, demonstrating that horticulture and plant science can be attractive to students from across the university if taught from an experiential perspective.

A Reciprocal International Student Travel Exchange

Iowa State University (ISU) and University of Costa Rica (UCR) have sustained a reciprocal student-group travel exchange program annually since 1999. The program focuses on characteristic crops and farm management practices in Iowa and Costa Rica. A 2015 survey of participants, described in Gleason et al. (p. 710), documented that the experience strongly influenced subsequent academic studies and career choices while also elevating cultural awareness, understanding, and tolerance on both sides of the exchange.

Low-input Landscape Rose Trial

Twenty landscape rose varieties were evaluated by Zlesak et al. (p. 718) at five U.S. locations using low-input, multi-year Earth-Kind® methodology. Four rose varieties had ≥75% plant survival and were in the top 50% for horticultural rating at all sites. Significant positive correlations were found between sites for horticultural rating, flower number, and flower diameter. Significant negative correlations were found between black spot lesion diameter from a laboratory assay and field horticultural rating at three sites. Cane survival was not significantly correlated with horticultural rating, suggesting some varieties can experience severe winter cane dieback, yet recover and perform well.

U.S. National Trials of Native Grass Varieties

Native grasses are important landscape plants for difficult sites, with many new varieties available. In a 3-year study in eight states (Colorado, Minnesota, North Carolina, Ohio, Oregon, Pennsylvania, Texas, Vermont), Meyer et al. (p. 731) evaluated 17 switchgrass and 5 little bluestem varieties. Despite wide variation from different regions, three of the 17 switchgrass varieties (Cloud 9, Northwind, and Thundercloud) had the highest performance for three characteristics across locations. ‘Shenandoah’ and ‘Warrior’ switchgrass, and Blue Heaven® little bluestem had high ratings for two traits across locations. This range of variability in landscape plant performance demonstrates the importance of local plant evaluations.

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