Nursery Crops Research Articles

Comparing Vegetative Propagation of Two ‘Schipkaensis’ Common Cherrylaurel Ploidy Levels

‘Schipkaensis’ common cherrylaurel (Prunus laurocerasus) is an important nursery crop across the United States. In our breeding efforts to reduce shot-hole symptoms and weediness, we have created chromosome doubled forms of this cultivar. Vegetative propagation is an important factor in nursery production, and we have found no studies that have looked at comparative adventitious rooting of stem cuttings using induced polyploids. The objective of this research was to determine if rooting ability varied between these two ploidy levels. Semihardwood stem cuttings from wild-type (22x) and polyploid (44x) ploidy levels were taken at the end of July 2015 and the beginning of July 2016. Cuttings were dipped in 1030 ppm (0.10%) indole-3-butyric acid (IBA) and 660 ppm (0.066%) 1-naphthaleneacetic acid (NAA) before being set in rooting substrate. After 1 month, cuttings were removed from substrate and data collected. Data included; rooting percentage, root number per rooted cutting, average root length, and total root length. In 2015, 88% of the cuttings from the 44x plants and 63% of the cuttings from the 22x plants rooted. In 2016, 100% of cuttings from both ploidy levels rooted. In both years, average root length and total root length were similar between ploidy levels; however, cuttings from 22x plants generally had more roots than those from 44x. Chromosome-doubled ‘Schipkaensis’ common cherrylaurel rooted effectively, and produce transplantable cuttings similar to the standard ploidy.

Biology and Management of Thickhead (Crassocephalum crepidioides) in Ornamental Crop Production

Typically found in shadehouses and shaded areas of nursery production, thickhead grows aggressively in containers and can outcompete nursery crops for water, nutrients, and light. This erect, sparingly branched, herbaceous annual, grows up to 4 feet tall and germinates over a wide range of pH, salt, and temperature conditions. This four-page fact sheet describes thickhead (Crassocephalum crepidioides) and various methods for its control in ornamental crop production. Written by Allison Bechtloff, Shawn Steed, Chris Marble, and Nathan Boyd and published by the Environmental Horticulture Department.­http://edis.ifas.ufl.edu/ep534

Effect of Topdressed Controlled-release Fertilizer Rates on Nursery Crop Quality and Growth and Growing Substrate Nutrient Status in the Niagara Region, Ontario, Canada

The objectives of the current study were to 1) determine the best topdressed controlled-release fertilizer (CRF) application rates for quality and growth of two nursery crops under temperate climate outdoor nursery production conditions in the Niagara region, Ontario, Canada, and 2) evaluate the nutrient status of the growing substrate following topdressing of two CRF types during the growing season. Fall-transplanted Goldmound spirea (Spiraea ×bumalda ‘Goldmound’) and Wine & Roses® weigela [Weigela florida (Bunge) A. DC. ‘Alexandra’] were grown in 2-gal (7.56 L) containers and topdressed on 7 May 2015 with Osmocote Plus 15N–3.9P–9.9K, 5–6 month CRF or Plantacote 14N–3.9P–12.5K, 6 month Homogeneous NPK with Micros. CRF was applied at rates of 1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 g nitrogen (N)/pot for both species. The best plants at the end of the growing season (i.e., 23 Sept. 2015) were spirea at 3.0–4.5 and 3.0–6.0 g N/pot, and weigela at 3.0–4.5 and 6.0 g N/pot, with Osmocote and Plantacote, respectively. At CRF rates above these rates, the majority of plants showed no increase in growth or quality attributes. All weigela plants, despite CRF application rate, showed K deficiency symptoms during the study. Using marketable-size criteria and plant growth data over time, estimates of production timing are presented for fall-transplanted, spring-topdressed weigela and spirea. These estimates may assist growers in choosing CRF application rates to meet time-sensitive production goals. Early in the growing season, NO3-N and P concentrations in the growing substrate were highest at CRF rates ≥4.5 and ≥6.0 g N/pot, respectively, and P continued to be high in August and September at 9.0 g N/pot. NH3-N and K concentrations at all CRF application rates were greater early in the growing season and decreased over time. At high CRF rates toward the end of the growing season, concentrations of NO3-N, NH3-N, and P once again increased. Considering crop-specific CRF application rates and understanding changes in growing substrate nutrient status during the growing season may help nursery growers prevent negative environmental impacts from over-fertilizing.

EVALUATING TWO RAINWATER HARVESTING SYSTEMS IN AN URBAN SETTING IN OREGON'S WILLAMETTE VALLEY

INTRODUCTION The recent trend toward more extreme periods of drought has been a shock to the residents of the Pacific Northwest – many of whom have relied upon heavy wateruse in the summer months in order to make a living (i.e. producers of grass seed and sod, berries, or nursery crops), or to maintain their landscapes at high levels (i.e. certain homeowners, recreational facilities, or commercial properties). Furthermore, population growth has reached the point where even an average year of precipitation has proven insufficient for urbanities that had not previously experienced issues with water scarcity (McDonald et al., 2011). This modern climate scenario has forced people of the Pacific Northwest, and people from all around the world, to rethink their water-use strategies, as the global trend has shifted toward greater sustainability (Tilman, 2001; McDonald et al., 2011). One potential mitigation strategy for cool-humid regions, such as Oregon's Willamette Valley, is to utilize rainwater-harvesting systems to alleviate freshwater demand (Kinkade-Levario, 2007). Rainwater harvesting is a logical choice for this climate zone because the average annual precipitation (42.7-in for Corvallis, OR) is sufficient for the majority of its crop production, however, this precipitation occurs almost exclusively in a nine-month period spanning from fall to spring (US Climate Data, 1981–2010). Although annual precipitation is adequate, irrigation is still required for at least three months of every year. This study considered rainwater harvesting to be ideally suited for the cool-humid Willamette Valley; the excess rainfall in the wet season that could be stored for use in the summer months, thus decreasing demand for municipal water by an equivalent amount. It should be stated that rainwater harvesting is not a novel idea; there have been studies dating back to the 1980's and earlier that have shown significant watersavings when retrofitting homes with new features like rainwater-harvesting systems (Boers et al., 1982, Karpisack et al., 1990). Even before that, golf courses, sporting complexes, and industrial sites alike were making use of this strategy. However, their methods typically consisted of catching rainwater via surface runoff and storing it in retention ponds (Ferguson, 1998), which is a strategy that is less applicable to the small-acreage homeowner who wants to irrigate their property without having to turn half of their backyard into a pond. Fortunately, there are alternative methods of rainwater harvesting that make a lot more sense in a residential setting, where irrigated land is small in relation to the roof-area for which rain can be easily harvested. This study documents the construction of two distinct rainwater-harvesting systems (an aboveground cistern and a belowground AQUABLOX™ matrix storage system), and gives insight into their advantages and disadvantages.

Thermal Weed Control in Photinia x fraseri “Red Robin” Container Nurseries

Abstract. A near-zero tolerance policy on weeds by markets for nursery crops calls for weed-free container-grown plants, and forces growers to frequently remove weeds. Thermal weed control could represent a novel method to control weeds in shrubs from container nurseries, thus avoiding the use of herbicides and mulches. The aims of this study were to develop custom-built machinery for thermal weed control in container nurseries and to test the weed control efficiency of flame weeding and steaming in Photinia x fraseri “Red Robin” containers. A liquefied petroleum gas (LPG) fed flamer and a steamer with a dedicated diffuser were built. Four treatments were applied for a total period of 24 months: steaming once every four months, steaming once every two months, flame weeding once every two months or once a month. Temperature values measured at different depths in the substrate after thermal applications were recorded and analyzed. Photinia x fraseri features (height, diameter, and dry biomass) and aesthetic parameters as affected by thermal treatments were also evaluated. The trend in temperature values of the substrate over time followed a two-phase exponential decay. All the thermal treatments lead to a continuous near-100% weed control level, which is the level required by growers for aesthetic reasons. No damages caused by heat on Photinia x fraseri were observed. Container nursery producers could thus adopt thermal methods as a substitute for chemical solutions for weed control management. Keywords: Container nurseries, ornamental plant production, Thermal weed control, Flame weeding, Steaming, Photinia x fraseri “Red Robin”, Two-phase temperature decay model.

Advantages and Disadvantages of Asynchronous Online Extension Programming for Delivering Master Producer Content

Budget reductions for the Cooperative Extension Service have made traditional extension programming (face-to-face, live programming) difficult for extension professionals. Attending traditional extension programming can also prove to be challenging for industry practitioners due to the need to delay or reschedule work activities and the need to travel to participate. The Tennessee Master Nursery Producer program (TMNP) is a professional development extension program designed to enhance the sustainability of the Tennessee nursery crops industry. The TMNP was first offered as a traditional extension program in 2012. Although the program was successful, it demanded substantial time from faculty and staff to coordinate the program, prepare presentations, and travel. Recurring travel expenses required a significant financial commitment from both extension personnel and participants. An asynchronous online program was developed to address these challenges and to increase accessibility, exploit the economies of scale, and standardize curriculum. The objective of this article is to describe the advantages and disadvantages that were identified offering nursery production subject matter as a traditional live classroom and subsequently as an asynchronous online program in terms of development cost, administrative and technological requirements, and economic impacts.

Micronutrient Availability from Steel Slag Amendment in Pine Bark Substrates

Steel slag is a byproduct of the steel industry that can be used as a liming agent, but also has a high mineral nutrient content. While micronutrients are present in steel slag, it is not known if the mineral form of the micronutrients would render them available for plant uptake. The objective of this research was to determine if steel slag could be used as the sole micronutrient source for container-grown nursery crops. Butterfly bush (Buddleja davidii ‘Pink Delight’) and rose (Rosa ‘Radrazz’) were grown in #3 (3 gal) containers in a base substrate composed of pine bark and peatmoss (80:20, by vol). The base substrate was amended with the following treatments: with a complete controlled release fertilizer (CRF) including micronutrients (C-control), a substrate amended with a different CRF containing only N, P, and K along with a granular micronutrient package (M-control), and three additional treatments amended with the CRF (N, P, and K only) and either 1.2, 2.4, or 4.8 kg·m−3 (2, 4, and 8 lb·yd−3) of steel slag. Plants were harvested at 2 and 4 months after potting (MAP). None of the plants displayed any sign of nutrient deficiency or toxicity throughout the experiment. However, plants grown in the substrate amended with the highest slag rate [4.8 kg·m−3 (8 lb·yd−3)] had lower shoot dry weight (SDW) than both control groups. Substrate pH increased with increasing slag rate, which may have affected micronutrient availability in those substrates. Among the micronutrients analyzed, only Copper (Cu) was consistently deficient in both the substrate and foliar tissue of slag-amended treatments. Steel slag either does not provide a sufficient quantity of Cu or the concomitant increase in pH with increasing rates of steel slag renders Cu unavailable for plant uptake. Steel slag should not be used as the sole source of micronutrients for shrubs grown in pine bark-based substrates.

Impact of Application Rate, Timing, and Indaziflam Formulation on Early Postemergence Control ofOxalis stricta

Although primarily used as an effective PRE herbicide, indaziflam has been shown to provide early POST control of some weeds commonly found in nursery production. Previous investigation on the early POST efficacy of indaziflam focused on the liquid formulation, and the ability of the granular formulation to provide early POST weed control is unknown. Nursery trials were conducted to evaluate early POST control of oxalis using two formulations of indaziflam. Oxalis seeds were surface sown to nursery containers at two separate dates and grown until they reached the two- to four-leaf stage (2-4L) and six- to eight-leaf stage. Both growth stages were treated with indaziflam at 12.6, 25.1, 50.2, and 100.4 g ai ha−1using either a granular (G) or liquid (SC) formulation. A chemical control treatment (glyphosate) and a nontreated control were also included for comparison. The SC formulation provided > 90% control of both oxalis growth stages at all four rates and was similar to glyphosate. The G formulation at 12.6 and 25.1 g ha−1only provided marginal control, but overall performed similarly to the SC formulation at the 50.2 and 100.4 g ha−1rate in most experiments. In contrast to the SC formulation, the G formulation is labeled for use over the top of container-grown nursery crops. Results of this research indicate that in areas where oxalis is the primary weed of concern, the G formulation of indaziflam could be applied to control small oxalis up to the 2-4L stage at the currently labeled rate (50.2 g ha−1).

Gall-ID: tools for genotyping gall-causing phytopathogenic bacteria.

Understanding the population structure and genetic diversity of plant pathogens, as well as the effect of agricultural practices on pathogen evolution, is important for disease management. Developments in molecular methods have contributed to increase the resolution for accurate pathogen identification, but those based on analysis of DNA sequences can be less straightforward to use. To address this, we developed Gall-ID, a web-based platform that uses DNA sequence information from 16S rDNA, multilocus sequence analysis and whole genome sequences to group disease-associated bacteria to their taxonomic units. Gall-ID was developed with a particular focus on gall-forming bacteria belonging to Agrobacterium, Pseudomonas savastanoi, Pantoea agglomerans, and Rhodococcus. Members of these groups of bacteria cause growth deformation of plants, and some are capable of infecting many species of field, orchard, and nursery crops. Gall-ID also enables the use of high-throughput sequencing reads to search for evidence for homologs of characterized virulence genes, and provides downloadable software pipelines for automating multilocus sequence analysis, analyzing genome sequences for average nucleotide identity, and constructing core genome phylogenies. Lastly, additional databases were included in Gall-ID to help determine the identity of other plant pathogenic bacteria that may be in microbial communities associated with galls or causative agents in other diseased tissues of plants. The URL for Gall-ID is http://gall-id.cgrb.oregonstate.edu/.

The Next Ten Years: Strategic Vision of Water Resources for Nursery Producers

Nursery and greenhouse producers, research and extension faculty, and representatives from allied fields collaborated to formulate a renewed vision to address water issues affecting growers over the next 10 years. The authors maintained the original container irrigation perspective published in “Strategic vision of container nursery irrigation in the next ten years,” yet broadened the perspective to include additional challenges that face nursery crop producers today and in the future. Water availability, quality, and related issues continue to garner widespread attention. Irrigation practices remain largely unchanged due to existing irrigation system infrastructure and minimal changes in state and federal regulations. Recent concerns over urbanization and population growth, increased climate variability, and advancements in state and federal regulations, including new groundwater withdrawal limitations, have provided an inducement for growers to adopt efficient and innovative practices. Information in support of the overarching issues and projected outcomes are discussed within.

Fungal trunk diseases: a problem beyond grapevines?

Grapevine trunk diseases (GTDs) are caused by a broad range of taxonomically unrelated fungi that occur wherever grapes are grown and are the main biotic factor limiting vineyard productivity and longevity (Bertsch et al., 2013). GTDs cause untenable economic losses to the grapevine industry worldwide. For example, they are considered a ‘national crisis’ in France, where it has been estimated that 12% of the vineyards are currently economically nonviable due to these maladies causing losses of about €1 billion (Lorch, 2014). Because GTDs are chronic and there is currently no option to eradicate the infections, unproductive vineyards must be replanted, at a worldwide annual cost estimate of €1·132 billion (Hofstetter et al., 2012). The establishment, progress, severity and spread of GTDs have been associated with (i) drought, (ii) limited availability of effective fungicides, (iii) pressure to increase yields, (iv) lack of pruning wound protection due to cost of labour, and/or (v) poor low-quality propagation material. Growers are demanding solutions. Many vineyards with high GTD incidence were planted in the mid-to-late 1990s, during which wine-grape prices were increasing (Volpe et al., 2008). These vineyards were being replanted in the wake of phylloxera, and nurseries could barely meet the demand for grape plants. In 2009 researchers declared the worldwide impact of GTDs and prioritized research goals (Bertsch et al., 2009). Despite scientific advances, there are still unanswered questions, for example about how the pathogens spread and which climate conditions favour infection. This limits the efficacy of GTD management practices. Other crops, such as almond, pistachio and walnut, are now experiencing planting booms (INC, 2015). The significance of these and other tree crops is that they host some of the same GTD pathogens. While researchers fine-tune strategies for managing GTDs in grape, the pathogens may alternate to tree crops, thus endangering the productivity and longevity of orchards and vineyards alike. Recent reports of high disease incidence in pome and stone fruits, nut crops, small fruits and olive in California (Úrbez-Torres et al., 2013), Iran (Mohammadi et al., 2015), Italy (Carlucci et al., 2015), South Africa (Cloete et al., 2011) and Spain (Gramaje et al., 2012) highlight the need for a focus on this new set of hosts. The production systems are different; not all practices for GTD management in grape are feasible in tree crops, especially with dwindling numbers of skilled farm labourers. Tree crop nurseries are struggling to meet demands for plant material and, from our experience with GTDs, a lack of first-quality plants means that low-quality plants are sold, too. Are these plantings doomed to a lifetime of poor productivity? Is the sustainability of the fruit and tree nut industries at risk? Yours sincerely, David Gramaje et al.

Evaluation of Kaolin Clay as an Alternative Management Tactic for Japanese Beetle Feeding Damage in Grape Vineyards

The Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), is an exotic, introduced Scarab that has become one of the most widespread and destructive insect pest of turf, landscapes and nursery crops in the eastern United States. It also damages various fruit, garden and field crops. Evaluation of certain conventional and non-conventional control agents in a Wisconsin vineyard revealed that bifenthrin, a fourth generation synthetic pyrethroid, provided the greatest Japanese beetle adult control in choice and no-choice feeding bioassays. Bacillus thuringiensis gallariae (Btg) was also effective in both bioassays. However, Btg residual activity was relatively limited; its performance decreased five days after treatment. Kaolin clay provided effective Japanese beetle adult management via consistent adult feeding damage mitigation in both study years. Field tests showed that various application Kaolin clay rates were effective in minimizing feeding damage by Japanese beetle adults, and no adverse effects were observed on several important fruit quality characteristics such as sugar content (Brix), acidity, number of fruit produced per plant and fruit weight. Kaolin clay is an alternative, non-insecticide management tactic that can be employed by grape growers to minimize feeding damage by Japanese beetle adults and reduce the amount of conventional insecticide input needed to maintain grape quality.

Rice Hull Mulch Affects Germination of Bittercress and Creeping Woodsorrel in Container Plant Culture

Mulches are commonly used to control weeds in container nursery crops, especially in sites where preemergence herbicides are either not labeled or potentially phytotoxic to the crop. Parboiled rice hulls have been shown to provide effective weed control when applied 1.25 to 2.5 cm deep over the container substrate surface. The objective of this research was to determine if weed seed placement, above or below the mulch layer, affects flexuous bittercress or creeping woodsorrel establishment. Seeds of both species were placed either above or below rice hull mulch layers 0, 0.6, 1.3, or 2.5 cm deep in nursery containers with a 80 pine bark: 20 sphagnum peat moss substrate. Establishment of both weeds decreased with increasing mulch depth. Establishment of both species was generally greater from beneath the mulch compared to when seed were applied above the mulch. Light penetration through varying depths of rice hulls was determined with a spectroradiometer. Photosynthetically active radiation (PAR) decreased exponentially with increasing rice hull depth, and was less than 1 μmol·m-2·s-1 beneath depths greater than 1 cm. Germination of both species was determined in Petri dishes placed beneath varying densities of shade cloth. Flexuous bittercress germination responded quadratically to decreasing light level, but still germinated (13%) in complete darkness after 3 weeks. Creeping woodsorrel germination was not affected by light level and was high (92%) after 3 weeks. The role of light exclusion by rice hulls as a mechanism for controlling buried weed seed is discussed. Water retention immediately after irrigation, and for 24 hr following irrigation, was determined for a 2.5 cm layer of rice hulls, sphagnum peat moss, and pine bark. Rice hulls retained less water, and dried more quickly than peat moss or pine bark. The volumetric water content of the rice hull layer is less than 0.20 cm·cm-1 and what has been shown necessary for plant growth. Lack of water availability in the rice hull layer is discussed as the primary mechanism of control of weed seed above the mulch layer.

Anaerobically Digested Dairy Fiber in Soilless Potting Media for Herbaceous Perennials

Sphagnum peat moss has been a primary component of soilless potting media for decades; however, concerns over the sustainability of harvesting peat have fostered a search for renewable media components. Anaerobically digested dairy fiber (ADDF), a by-product of methane production, shows promise as an alternative to peat. Herbaceous nursery crops including “Jack Frost” brunnera (Brunnera macrophylla I.M. Johnst), “Moonbeam” coreopsis (Coreopsis verticillata L.), “Whoops-a-Daisy” Shasta daisy (Leucanthemum × superbum Bergmans ex J.W. Ingram), “Kobold Original” liatris (Liatris spicata (L.) Willd.) and “David” phlox (Phlox paniculata L.) were grown in media containing bark-peat-perlite or bark-ADDF-perlite in a 4:2:1 proportion. All leachate was collected from pots to evaluate cumulative nitrogen and phosphate leaching. Brunnera grew to a similar size and quality in both mixes, although brunnera in the bark-ADDF-perlite mix had slightly chlorotic leaf margins. Coreopsis grew to a similar size and quality in both mixes but was slightly etiolated and chlorotic in bark-ADDF-perlite. Shasta daisy grown in bark-ADDF-perlite were larger than those grown in bark-peat-perlite. Both mixes produced similar growth and quality liatris and phlox. More ammonium, nitrate and phosphate were recovered from leachate from bark-ADDF-perlite than from bark-ADDF-perlite.

Effect of Selective Foliar Insecticides onAmblyseius swirskii(Acari: Phytoseiidae), 2014

Amblyseius swirskii is a generalist predator, widely known for its biocontrol potential against multiple pests (mites, thrips, and whiteflies) of nursery and greenhouse crops. The objective of this study was to evaluate susceptibility of A. swirskii to conventional insecticides known to be effective against various greenhouse pests. The trial was conducted on an ornamental pepper cultivar “Masquerade” at U.S. Horticultural Research Laboratory, Florida to identify A. swirskii- compatible pesticides. Pepper plants were grown from seed in Fafard Pro-Mix (Canadian Formula; Conrad Fafard, Inc., Agawam, MA 01001-2907) medium in seedling trays and transplanted in 10.1 cm-diameter plastic pots when seedlings were ∼5-wk old. Plants …

Control ofFrankliniella occidentaliswith Foliar Insecticides, 2014

The objective of this study was to evaluate the efficacy of several insecticides against western flower thrips, a serious pest in greenhouse and nursery crop production in the United States. The trial was conducted on an ornamental pepper cultivar ‘Masquerade’ under greenhouse condition at the U.S. Horticultural Research Laboratory. Pepper plants were grown from seed in Fafard Pro-Mix (Canadian Formula; Conrad Fafard, Inc., Agawam, MA 01001-2907) medium in seedling trays and transplanted in 10.1 cm-diam plastic pots when seedlings were approximately 5 wk old. The greenhouse was maintained at 26 ± 3°C and 75–80% RH. Plants were spaced at 1.5 × 1.5 ft, watered as …

Genome Sizes and Ploidy Levels in the Genus Kalmia

Kalmia is a highly ornamental genus of shrubs native to North America and Cuba and grown as a valuable nursery crop throughout much of the temperate world. Although most species of Kalmia have previously been found to be diploid with 2n = 2x = 24, one species, Kalmia polifolia, has been found to be tetraploid. However, sampling within the genus has been limited, and information on the ploidy levels of specific cultivars is lacking. The objective of this study was to determine the relative genome sizes and ploidy levels of species, hybrids, and cultivars of Kalmia. Flow cytometry was used to determine the relative genome sizes of 67 accessions representing species, interspecific hybrids, cultivars, and chemically induced polyploids. Traditional cytology was used to calibrate genome sizes with ploidy levels. Results showed that relative genome sizes were conserved with 1Cx values ranging from 0.57 pg for Kalmia carolina to 0.70 pg for Kalmia latifolia. Most species of Kalmia were diploid including K. buxifolia (Leiophyllum buxifolium), K. carolina, K. cuneata, K. hirsuta, K. latifolia, and K. microphylla. Although plants of K. carolina (Kalmia angustifolia var. carolina) were uniformly diploid, the closely related, but more northerly distributed, K. angustifolia was primarily tetraploid, providing additional justification for treating these as separate species. An unusual triploid of K. angustifolia f. candida was also documented. Kalmia polifolia included both tetraploid and potentially pentaploid individuals, indicating a ploidy series within this species. Kalmia latifolia cultivars also included one triploid, two cytochimeras, and two chemically induced tetraploids. Overall, polyploidy was more prevalent in Kalmia than previously reported and varied both within and among species. This broader survey of relative genome sizes and ploidy levels in Kalmia provides valuable information for plant breeders and new insights into the systematics and cytogenetics of the genus.

Improving nursery production of fifteen California native plant species: the effect of air-filled porosity

Many studies have shown the importance of air-filled porosity (VA ) for optimal growth and dry weight of container-grown plants, but few have examined its effects on California native plants. Anecdotal evidence suggests that various upland native species require higher substrate aeration or less frequent irrigation than do standard nursery crops. We tested effects of VA and irrigation frequency on 15 California native species that had been identified by growers as challenging because of their aeration needs and sensitivity to overwatering. Plants were grown in substrates with 10% or 22% VA and were irrigated once (up to 574 ml) or twice daily (up to total of 972 ml). None of the applied treatments preferentially influenced plant survival or growth. Results indicate that these species may tolerate both normal and high VA values. The high survival and growth rates in these experiments indicate that growers’ experiences of plant death or poor plant growth are attributable to something other than VA .

Survey of Reclaimed and Non-reclaimed Irrigation Water Use for Production of Container-grown Plants in Florida

A descriptive survey was conducted of container plant growers using reclaimed water (processed sewage) for irrigation of nursery crops and growers whose businesses were located in areas where reclaimed water was available but not used for irrigation. Surveys were completed during site visits except when participants wanted to complete the survey at a later time. Nurseries using reclaimed water produced trees, shrubs, perennials, bedding plants, foliage plants, and potted flowering plants. Average area outdoors or under shade irrigated with overhead sprinklers was 3.5 ha (8.6 A) and 10,777 m2 (116,000 ft2) for greenhouses. Participants responded that reclaimed water quality (67%) and quantity (50%) were consistent over time. All reclaimed water users were satisfied with both quality and quantity of reclaimed water. Most growers (83%) not using reclaimed water were using well water as the primary source of water. Seventy-one percent of non-reclaimed users responded that expense of connection to reclaimed water was a limitation, while 57% indicated that unknown water quality and health or safety concerns were limitations. Results from this survey indicated acceptance of reclaimed water among active users and the need for education about reclaimed water for non-reclaimed users.

Seasonal and Spatial Dispersal Patterns of Select Ambrosia Beetles (Coleoptera: Curculionidae) from Forest Habitats into Production Nurseries

Abstract Exotic ambrosia beetles (Coleoptera: Curculionidae) are important pests of ornamental tree nurseries. Although these beetles reportedly disperse in early spring from peripheral forested areas into nurseries, few studies have determined how far they fly to infest new host trees, or whether a masstrapping strategy can adequately protect a nursery crop. Field monitoring with ethanol baits in South Carolina (2011–2012), Mississippi (2013–2014), and Louisiana (2013–2014), USA, determined the timing of peak ambrosia beetle flights, dispersal distance, and optimal trap location. In addition to the well-documented spring flight peak, southeastern nursery managers may need to be aware of a second, late-summer flight. Captures from traps placed in a nursery at various distances (−25 to 200 m) from the forest—nursery interface showed a significant linear and quadratic trend in decreasing numbers of beetles captured with increasing distance from the forest in South Carolina, whereas significant linear, quadr...