Outdoor Container Research Articles

Влияние обработки фиторегуляторами на декоративные качества растений Tagetes patula L. сорта Петит гармония в условиях контейнерного содержания

The article considers the issues of the influence of treatment with Zircon and tank mixtures Zircon-Siliplant, Zircon-Ecofus to increase the decorative indicators of tagetes of the rejected variety Petit harmony in conditions of outdoor container content. As a result of the experiment, a reliable effect of the use of growth-regulating drugs on morphometric parameters was established. The article provides data on the positive effect of the drugs on the decorative qualities of the rejected tagetes. Keywords: CONTAINER FLORAL DECORATION, DECORATIVE QUALITIES OF FLORAL COMPOSITIONS, AESTHETIC QUALITIES OF FLORAL DECORATION, FLOWERING PRODUCTIVITY, GROWTH REGULATORS, GROWTH STIMULANTS, PHYTOREGULATORS, GROWTH REGULATORS, MICRO FERTILIZERS, ORGANO-MINERAL FERTILIZER, TAGETES REJECTED

Health seeking behaviours, dengue prevention behaviours and community capacity for sustainable dengue prevention in a highly dengue endemic area, Sri Lanka

Introduction Dengue has become a major health problem in globally as well as locally. The delay in health-seeking is significantly associated with complications leading to severe dengue and active engagement of communities needs to minimize the delays in management to control epidemics. The aim of the study was to evaluate the relationship between sociodemographic characteristics and householders' Health-Seeking Behaviours (HSB), Dengue-Prevention Behaviours (DPB), and Community Capacities (CC) for sustained dengue prevention in Sri Lanka, a country with a high dengue endemicity.MethodsA cross-sectional analytical study was carried out in a district with the highest dengue endemicity from January to April 2019. Of the householders, 532 were chosen randomly. A pre-tested, validated, and interviewer-administered questionnaire was used to assess HSB and DPB. The HSB was assessed using three aspects, initial response for fever management, the duration of blood testing and initial response if suspected dengue. The DPB assessment was evaluated using ‘waste, outdoor water container, indoor water container, roof gutter and water storage management’. ‘Dengue Community Capacity Assessment Tool’, with 14 key items was used to assess the level of community capacity for dengue prevention. Out of the total, ≥ 50% was considered as an “adequate” HSB, DPB and CC. Multiple logistic regression was performed to control confounding effects. The results were expressed as adjusted Odds-Ratios (aOR) and 95% Confidence Intervals (CI).ResultsThe response rate was 93.2% (n = 496). Among them, 44.6% (n = 221) had adequate overall HSB, and 19.2% (n = 95) had adequate DPB. Householders who have ≤ 4 family members are 1.74 times (aOR = 1.74; 95% CI: 1.17 – 2.61) more likely to have adequate HSB and 1.85 times (aOR = 1.85; 95% CI: 1.11 – 3.09) more likely to have adequate DPB. The age group of 46 to 70 years’ individuals (aOR = 1.74; 95% CI:1.12 – 2.92), and who engaged in employment (aOR = 1.68; 95% CI: 1.05 – 2.67) were more likely to have adequate DPB than the group of 18 to 45 years and the non-employed individuals respectively. Of them, 24.6% (n = 122) perceived that they have adequate CC. The householders who have per-capita income < USD 50 are 1.95 times (aOR = 1.95; 95%CI:1.11 – 3.40) more likely to have adequate CC.ConclusionThe HSB, DPB and CC need to be improved to change the behaviour for sustainable dengue prevention and community capacity-building programmes need to be conducted in the Kurunegala district, Sri Lanka.

Dengue Control Model, Abate Sowing and Larvitrap Installation in Dengue Endemic Areas of Kupang City

The bite of the Aedes sp mosquito causes nearly 0 million people to be infected with the dengue virus annually, one of areas declared as an endemic area is East Nusa Tenggara Province. 5669 cases and 58 deaths due to dengue hemorrhagic fever (DHF) were found in East Nusa Tenggara Province in 2020 (CFR 1.02%). Highly influential external factors include the availability of clean water, the crisis of drinking water and clean water, and poor condition of water container that do not meet the requirements. This study aims to manage Larvitrap installation movement and abatezation of the water containers in the community/households in Kupang City. This was a observational study with survey design regarding the installation of Larvitrap tool. The density of mosquito larvae was measured based on the House Index (HI), Container Index (CI), and Breteau index (BI). 383 families were involved as the study samples who were selected using the accidental sampling technique. The results showed that there were 866 units of water resevoir (47.8%). Fatululi Village had the highest percentage of indoor water container by 15.7% (140 units), and Oesapa Village had the highest percentage of outdoor water container by 15.5% (143 units). The highest percentage of positive indoor water container was found in TDM and Kelapa Lima by 30.4%, while the highest percentage of positive outdoor water container was found in TDM village by 48.4%. Aedes aegypti larvae and Aedes albopictus larvae were identified in the indoor and outdoor water containers in TDM Village, while that were only aedes aegypti larvae found in six other villages. The positive larvitrap larvae found in Oebufu Village was 15%, 10% was found in Oesapa Village, while there were no larvae found in 5 other villages. The flick density index obtained the highest House Index (HI) in Kelapa Lima village by 58.33%, the highest Container Index (CI) was found in TDM village by 44.03% and the highest Breteau Index (BI) was found in TDM village by 218.75%. It can be concluded that it is necessary to conduct education on mosquito larvae control that involves active community participation and supervision towards weekly draining of community water containers. In addition, abate sprinkling and dengue vector control activities should be carried out simultaneously throughout Kupang City at the beginning of the rainy season, at the peak of case incidence and at the end of the rainy season.

Durable radiative cooling against environmental aging

To fight against global warming, subambient daytime radiative cooling technology provides a promising path to meet sustainable development goals. To achieve subambient daytime radiative cooling, the reflection of most sunlight is the essential prerequisite. However, the desired high solar reflectance is easily dampened by environmental aging, mainly natural soiling and ultraviolet irradiation from sunlight causing yellowish color for most polymers, making the cooling ineffective. We demonstrate a simple strategy to use titanium dioxide nanoparticles, with ultraviolet resistance, forming hierarchical porous morphology via evaporation-driven assembly, which guarantees a balanced anti-soiling and high solar reflectance, rendering anti-aging cooling paint based coatings. We challenge the cooling coatings in an accelerated weathering test against simulated 3 years of natural soiling and simulated 1 year of natural sunshine, and find that the solar reflectance only declined by 0.4% and 0.5% compared with the un-aged ones. We further show over 6 months of aging under real-world conditions with barely no degradation to the cooling performance. Our anti-aging cooling paint is scalable and can be spray coated on desired outdoor architecture and container, presenting durable radiative cooling, promising for real-world applications.

Costs and benefits of hosting &lt;i&gt;Epichloë&lt;/i&gt; endophytes: a comparison of three haplotypes in &lt;i&gt;Lolium perenne&lt;/i&gt; with contrasting effects on two herbivores

The symbiotic relationship between Lolium perenne and Epichloe festucae var. lolii, a fungal endophyte that lives asymptomatically in its above-ground parts, benefits both the host and fungus. In an outdoor container experiment, the effects of three distinct endophyte haplotypes (AR1, AR37 and CT) on natural infestations of a root aphid, Aploneura lentisci and a mealybug Phenococcus graminicola were compared with an endophyte-free (Nil) control. Populations of these insects were suppressed in a genetically identical set of plants treated with insecticide. Over 18 months, foliar and root growth, tiller numbers and plant mortality were compared between the different endophyte treatments and between insecticide-treated and untreated plants. Hyphal densities were recorded once during the trial. Untreated plants infected with AR37 had the lowest populations of A. lentisci and P. graminicola, and the highest root and foliar growth compared with other treatments. Growth parameters of untreated plants infected with CT often exceeded that of AR1 and Nil due to low infestations of P. graminicola and lower populations of A. lentisci. Growth of Nil, AR1 and CT plants were higher in insecticide-treated than in corresponding untreated plants but was unaffected in AR37. Untreated Nil and AR1 plants had a lower survival than AR37 and CT plants. Cumulative root outgrowth for treated AR37 plants was significantly lower than for treated AR1 on three sampling occasions. These Epichloe haplotypes are primarily mutualists, although there are circumstances when they may be disadvantageous to their host. Opposing outcomes likely originate in the ecosystems in which associations evolved.

Emergence of garden spurge (Euphorbia hirta) and large crabgrass (Digitaria sanguinalis) in response to different physical properties and depths of common mulch materials

AbstractGreenhouse and outdoor container experiments were conducted to determine garden spurge and large crabgrass emergence when seeds were placed either on top of or below three different mulch materials [pine bark (PB), hardwood (HW), or pine straw (PS)] applied at five depths (0, 1.3, 2.5, 5.1, and 10.2 cm). To elucidate mulch characteristics that contributed to weed control, photosynthetic active radiation (PAR) was recorded underneath each mulch layer, moisture retention was monitored for 24 h following irrigation, and particle size was determined using standard soil sieves. HW reduced PAR (97%) more than did PB (90%) or PS (92%) at 1.3 cm, but few or no differences were noted between mulches at greater mulch depths. HW also contained the highest percentage of small particles and consequently retained more water (29%), than PB (14%) or PS (22%) 24 h following a simulated irrigation event. Emergence of large crabgrass and garden spurge was consistently greater when seeds were placed on top of the mulch, compared to seeds placed below. Emergence of both species also tended to respond to increasing depth in a quadratic manner, indicating that once a critical level of mulch was applied (2.5 to 5 cm), further reductions in weed emergence would not be observed, at least over the short term (12 wk). PB and PS tended to provide a greater reduction in emergence of both species compared to HW. This research also indicates that larger particle materials such as PB or PS would be advantageous because of their ability to suppress weed emergence regardless of seed position.

Distribusi dan Karakteristik Tempat Perkembangbiakan Aedes aegypti serta Perilaku Masyarakat di Daerah Endemis Demam Berdarah Dengue di Salatiga

Human behavior in form of less awareness about the environment will cause the increase of mosquito breeding places and lead to increase the dengue vector’s population rising. This research’s purpose was to describe distribution and characteristics of the dengue vector’s breeding place and people behavior in dengue endemic areas in Salatiga. The data collection was done by monitoring larvae and pupa on water container and interviewing community about related behavior. Results showed that larvae tend to be found in water storage containers, household appliances and open unused goods which was located inside the house. Based on the analysis, there is no significant difference between the indoor and outdoor container, the container is closed or open, and sprinkled with temephos or not. Significant differences were found in different types of containers, containers with fish and drained in the last one week. People in DHF endemic area tend to conduct 3M (Menguras/drain and Menutup/close the lid of Water Reservoirs and Mengubur/bury unused container that have potential as breeding places) and do not use fish nor larvacide for dengue vector control. Based on the result of the research, it is necessary to evaluate the community behavior in closing container and also evaluate the resistance of DHF vector mosquito to temephos.

Evaluating On-demand Irrigation Systems for Container-grown Woody Plants Grown in Biochar-amended Pine Bark

Controlling irrigation using timers or manually operated systems is the most common irrigation scheduling method in outdoor container production systems. Improving irrigation efficiency can be achieved by scheduling irrigation based on plant water needs and the appropriate use of sensors rather than relying on periodically adjusting irrigation volume based on perceived water needs. Substrate amendments such as biochar, a carbon (C)-rich by-product of pyrolysis or gasification, can increase the amount of available water and improve irrigation efficiency and plant growth. Previous work examined two on-demand irrigation schedules in controlled indoor (greenhouse) environments. The goal of this study was to evaluate the impact of these on-demand irrigation schedules and hardwood biochar on water use and biomass gain of container-grown Hydrangea paniculata ‘Silver Dollar’ in a typical outdoor nursery production environment. Eighteen independently controlled irrigation zones were designed to test three irrigation schedules on ‘Silver Dollar’ hydrangea grown in pine bark amended with 0% or 25% hardwood biochar. The three irrigation schedules were conventional irrigation and two on-demand schedules, which were based on substrate physical properties or plant physiology. Conventional irrigation delivered 1.8 cm water in one event each day. The scheduling of substrate-based irrigation was based on the soilless substrate moisture characteristic curve, applying water whenever the substrate water content corresponding to a substrate water potential of –10 kPa was reached. The plant-based irrigation schedule was based on a specific substrate moisture content derived from a previously defined relationship between substrate moisture content and photosynthetic rate, maintaining the volumetric water content (VWC) to support photosynthesis at 90% of the maximum predicted photosynthetic rate. Total water use for the substrate-based irrigation was the same as for the conventional system; the plant-based system used significantly less water. However, plant dry weight was 22% and 15% greater, water use efficiency (WUE) was 40% and 40% greater, and total leachate volume was 25% and 30% less for the substrate-based and plant-based irrigation scheduling systems, respectively, than for conventional irrigation. The 25% biochar amendment rate reduced leachate volume per irrigation event, and leaching fraction, but did not affect total water use or plant dry weight. This research demonstrated that on-demand irrigation scheduling that is plant based or substrate based could be an effective approach to increase WUE for container-grown nursery crops without affecting plant growth negatively.

Comparative Water and Nutrient Application Rates among Ornamental Operations in Maryland

Quantifying the range of fertilizer and irrigation application rates applied by the ornamental nursery and greenhouse industry is challenging as a result of the variety of species, production systems, and cultural management techniques that are used. To gain a better understanding of nutrient and water use by the ornamental industry in Maryland, 491 potential operations (including multiple addresses and contacts) in the state were mailed a packet of information asking for their voluntary participation. Of the 491 potential operations, it was determined that 348 operations were currently in operation. Of those 348 operations, 48 (14% of the operations in the state) participated in a site visit and an in-depth interview, and a detailed site analysis of the water and nutrient management practices was performed on a production management unit (MU) basis. The authors define an MU as a group of plants that is managed similarly, particularly in regard to nutrient and irrigation application. Greenhouse operations reported, on average, 198, 122, and 196 kg/ha/year of nitrogen (N), phosphorus (P, as P2O5), and potassium (K, as K2O) fertilizer used, respectively, for 27 operations, representing 188 MUs. Twenty-seven outdoor container nursery operations had a total of 162 MUs, with an average of 964, 390, and 556 kg/ha/year of N, P2O5, and K2O fertilizer used, respectively. Field nursery (soil-based) operations were represented by 17 operations, producing 96 MUs, with an average of 67, 20, and 25 kg/ha/year of N, P2O5, and K2O fertilizer used, respectively. Irrigation volume per application was greatest in container nursery operations, followed by greenhouse and field nursery operations. Data were also analyzed by creating quartiles, which represent the median of the lowest 25%, the middle 50%, and highest 75% of values. It is likely that the greatest quartile application rates reported by growers could be substantially reduced with little to no effect on plant production time or quality. These data also provide baseline information to determine changes in fertilization practices over time. They were also used as inputs for water and nutrient management models developed as part of this study. These data may also be useful for informing nutrient application rates used in the Chesapeake Bay nutrient modeling process.

Impact of wind speed on ventilation performance within a container installed with photovoltaic inverter

PV inverter needs proper ventilation for reducing the heat dissipation of the electronic components. In this work, a container installed with PV inverter is considered with different configurations of cooling channels within the container for ventilation analysis. Typically, high capacity PV inverters are installed inside the container and therefore inverters, are not experiencing external wind effects and it depends on the configuration of cooling channels. In this work, the main cooling channel is located at the top of the inverter; inlet and outlet ventilation holes are located on the side of cross ventilation. They help in analyzing the cooling design, dependent on site specific wind flow direction of a container. Wind speeds and their directions can raise back pressures, which may be high enough to block the cooling air flow inside the channels. Reduction of cooling air flow reduces the fan capacity for dissipating the heat losses. In this study, cooling performance of outdoor container installed with PV inverter has been evaluated by using the Computational Fluid Dynamics (CFD) with two separate commercial packages, ANSYS CFX and Mentor Graphics FloEFD. Full scale size PV inverter prototype model has been used for experimental testing using the facility of the Wind Driven Rain equipment testing of the Toptester Limited (Finland). CFD numerical simulation results have been validated by comparing with the measured/experimental results. Wind flow volume rate results investigations have shown the cooling flow drop consequently with the head wind strength and also it has displayed the axial fan saddle region effect on the volume flow. Both the measurements and CFD results have shown significant turbulence in the inlet vent region of the main cooling channel.

Response of corn silage (Zea mays L.) to zinc fertilization on a sandy soil under field and outdoor container conditions

The purpose of the experiments was to evaluate zinc (Zn) fertilization effect on growth, yield and yield components of corn silage grown on a sandy soil under field and outdoor container conditions. Six rates of Zn supply (0 or control; 1.5; 3; 5; 10 and 50mgkg−1) were tested. They were split at three different times during the growing season: (i) 50% immediately after sowing, (ii) 25% at 4–5 leaf stage and (iii) 25% at 8–9 leaf stage. These Zn rates were applied to the soil surface as a solution of Zn sulfate (ZnSO4·7H2O). Zn deficiency symptoms appeared at an earlier stage (4–5 leaf stage) as white stripes between the midrib and the margin of leaves for a Zn rate below or equal to 5mgkg−1. Severity of these symptoms manifested more in container than in field. For both experiments, Zn supply induced a significant increase in stem height and leaf area. Furthermore, in both experiments, control plants showed a notable delay in achieving anthesis, silking, pollination and kernels maturity. The maximum shoot dry weight at harvest was recorded with Zn supply of 5mgkg−1 in field experiment and 10mgkg−1 in containers experiment. The shoot dry weight was especially linked to kernels dry weight. This latter was mainly enhanced through two compounds: 1000 kernels dry weight and pollination rate. On the other hand, outdoor container results can be used to help predict field plant responses to Zn except for control treatment.

Breeding triploid aspen and poplar clones for biomass production

AbstractEnriched diploid pollen was applied for in vitro pollinations and crossbreeding in the greenhouse to produce high performance triploid aspen and aspen hybrids for cultivation in medium rotation plantations. In addition to crossings within the section Populus, intersectional crossbreeding was performed to combine benefits of intersectional hybridization with those derived from triploidisation.Both the enrichment of diploid pollen by size fractionation of naturally unreduced pollen and heat treatment of microspore mother cells resulted in a distinct increase of diploid pollen. Using this pollen, six triploid plants were obtained from in vitro pollinations and twenty from crossbreeding in the greenhouse. The triploid plants displayed a high variability in growth performance. Two clones from in vitro pollination and five from crossbreeding in the greenhouse were chosen to estimate growth characteristics. A first assessment of clone performance in an outdoor container test con - ducted over one growing season revealed two triploid clones with a same stem height and a significantly increased basal stem diameter in comparison to the fast-growing triploid reference clone “Astria”. Crossbreeding experiments also resulted in two fast-growing mixoploid clones, which have already been stable for several years.All in all, in this study, crossbreeding using enriched diploid pollen is proved to be a reliable and applicable approach for an effective breeding of triploid poplars.

WHAT LIMITS AND HOW TO IMPROVE WATER USE EFFICIENCY IN OUTDOOR CONTAINER CULTIVATION OF ORNAMENTAL NURSERY STOCKS

Around the town of Pistoia (Tuscany, Italy) there is the most important centre in Europe for the cultivation of landscaping ornamentals, which typically require plenty of nutrients and water. Unfortunately, in these crops water use efficiency (WUE) is low as a consequence of over-irrigation, also due to the practice to place different plant species in the same cultivation plot, which results in the tendency to regulate irrigation on the basis of the most water demanding crop. This paper discusses how to improve WUE in outdoor container crops on the basis of an experiment conducted by simulating the cultivation of different ornamental species (Forsythia intermedia, Photinia × fraseri, Prunus laurocerasus and Viburnum tinus) in the same irrigation plot with the objective of: i) estimating the intra- and inter-specific variability in crop evapotranspiration (ET); ii) assessing water use and runoff in plot with irrigation controlled by a tensiometer placed in a reference plant (Prunus); iii) developing a simple model for ET based on plant height and reference ET. The main conclusion is that, compared to the traditional timer-based irrigation scheduling, substrate moisture sensor (SMS) can improve WUE of container crops even in nurseries characterized by a large inter-pot variability in ET as a consequence of the accustomed practice to place different crops in the same irrigation sectors. Due to the high number of irrigation plots in commercial nurseries, plenty of sensors must be installed and therefore it is crucial to design a cheap and low-maintenance SMS and a user-friendly irrigation control system based on a network of wireless sensors.

Genetic composition of resident populations influences establishment success of immigrant species

We conducted an outdoor container experiment to test the hypothesis that the genetic composition of resident populations influences the establishment success of immigrant species. We manipulated the genetic compositions (source populations) of populations of the water flea Daphnia magna, a strong competitor in pond and shallow lake zooplankton communities, and monitored the establishment success of immigrant cladoceran species of a regional species pool. We show that establishment success is affected by the source population of the resident D. magna as well as by the presence/absence of macrophytes and the presence/absence of fish in the containers. Our results provide evidence that the genetic composition of resident populations can impact community assembly and metacommunity dynamics, and that community genetics can influence ecosystem functioning.

Influence of mechanical rhizome cutting, rhizome drying and burial at different developmental stages on the regrowth of Calystegia sepium

SummaryThe regrowth of Calystegia sepium was studied in three types of experiments during spring 2003 and spring 2004. In one glasshouse experiment, rhizome fragments were planted in pots and either harvested at six different developmental stages to assess their undisturbed development and growth or harvested at 420 day degrees after burial to measure their regenerative capacity. Regrowth gradually declined as the plants had more expanded leaves at the time of burial. Minimum regenerative capacity was found when plants had four to eight fully expanded leaves and this coincided with the growth stage of minimum dry weight of underground regenerative organs. The effects of burial depth and rhizome fragment length were studied in outdoor container experiments. Burial at 15 or 25 cm reduced above‐ and below‐ground biomass in 2004, while 25 cm deep burial was necessary to reduce regrowth in 2003. Fragmentation had generally little effect on production of above‐ and below‐ground biomass, whereas burial and fragmentation delayed emergence time. Sensitivity of rhizomes to drying was studied in a growth chamber. Drying periods of 12 or 24 h did not have an influence on the production of aerial shoots, whereas 48 or 96 h reduced production of above‐ground biomass significantly. The experiments indicated that the minimum regenerative capacity would be at about 5–6 leaf stage and that mechanical disturbance at this stage would optimise weed control.

Growth and Flowering Response of Container Grown Passion Flower Cultivars to Fertilizer and Paclobutrazo

Abstract The effects of fertilizer and paclobutrazol applications on growth and flowering in four container grown passion flower cultivars (Passiflora ‘Amethyst’, Passiflora ‘Blue Bouquet’, Passflora ‘Fledermouse’, and Passflora ‘Lady Margaret’) were evaluated. A four month production system was used that included propagating cuttings in late winter, followed by greenhouse liner production in early spring, and finally by two months of outdoor container production. Shoot growth was increased by increasing fertilizer rates and the response was highly cultivar dependent. Fertilizer rates resulting in the highest levels of growth for each cultivar were generally higher than those required for most container grown nursery crops, ranging between 3.2 and 5.3 g/liter (0.44 and 0.73 oz/gal) of Osmocote 14N–6.0P–11.6K (14–14–14). Paclobutrazol reduced overall plant size without increasing the number of nodes or flowers. Cultivars were chosen based on cold tolerance and vigor and cultivar appeared to be the most significant independent variable. Of the cultivars evaluated ‘Lady Margaret’ was most suitable for the four month production system.

Degradation of Pesticides in Nursery Recycling Pond Waters

Recycling or collection ponds are often used in outdoor container nursery production to capture and recycle runoff water and fertilizers. Waters in recycling ponds generally have high concentrations of nutrients, pesticides, and dissolved organic matter, as well as elevated salinity and turbidity. Little is known about pesticide degradation behavior in the unique environment of nursery recycling ponds. In this study, degradation of four commonly used pesticides diazinon, chlorpyrifos, chlorothalonil, and pendimethalin in waters from two nursery recycling ponds was investigated at an initial pesticide concentration of 50 microg/L. Results showed that the persistence of diazinon and chlorpyrifos appeared to be prolonged in recycling pond waters as compared to surface streamwaters, possibly due to decreased contribution from biotic transformation, while degradation of chlorothalonil and pendimethalin was enhanced. Activation energies of biotic degradation of all four pesticides were lower than abiotic degradation, indicating that microbial transformation was less affected by temperature than chemical transformation. Overall, the pesticide degradation capacity of recycling ponds was better buffered against temperature changes than that of surface streamwaters.

Development ofOculimacula yallundaeandO. acuformis(eyespot) on leaf sheaths of winter wheat in the UK in relation to thermal time

In a controlled environment (15/10°C) (day/night) container experiment on winter wheat (cv. Avalon), eyespot incidence (percentage of plants affected) and number of leaf sheaths penetrated after 6 weeks increased with inoculum concentration (102−106conidia mL−1) ofOculimacula yallundae(OY) orOculimacula acuformis(OA), but there was no difference between the two species. In an outdoor container experiment, seedlings inoculated with OY 2 weeks after sowing had a greater incidence of eyespot than those inoculated with OA, when assessed 7 weeks after inoculation. Seedlings inoculated with OA at 10 or 20 weeks after sowing developed more severe eyespot by maturity than those inoculated with OY. In an experiment at 15/10°C with seedlings inoculated with OY + OA 2 weeks after sowing, more leaf sheaths were penetrated by OY (3·0 per plant) than OA (2·3 per plant) 6 weeks after inoculation. Field experiments with winter wheat consistently showed leaf sheath production, leaf sheath death, and number of leaf sheaths infected or penetrated by OA or OY were related linearly to thermal time (°C days) after sowing. Depending on cultivar, season and sample, a new leaf sheath was produced in 116–216°C days; a leaf sheath died in 221–350°C days; and infection of a new leaf sheath occurred in 129–389°C days. The mean number of living leaf sheaths infected differed between samples, cultivars and seasons for both OY and OA. Regression analysis of the 1985/86 data suggested that OY progressed more rapidly than OA through the leaf sheaths, and that both the pathogens progressed more rapidly than the rate of leaf sheath death, but more slowly than the rate at which leaf sheaths were produced. It also suggested that OA progressed more slowly than the rate at which leaf sheaths died in 1987/88, but OY did not.

Dose and Concentration Responses of Common Nursery Weeds to Gallery, Surflan and Treflan

Abstract Preemergence herbicides are applied as often as every eight to ten weeks in container nursery crop production in the southeastern United States. However, weeds often emerge before reapplication. Experiments were conducted to assess the minimum surface-applied doses and the in vitro concentrations of preemergence herbicides required to control susceptible weed species. Greenhouse and outdoor container experiments were conducted to determine surface-applied Treflan (trifluralin) doses required to control large crabgrass and perennial ryegrass. In the greenhouse, 0.8 to 1.1 kg ai/ha (0.7 to 1.0 lb ai/A) was necessary for 6 weeks control. Outdoors, 1.5 to 1.9 kg ai/ha (1.3 to 1.7 lb ai/A) was needed for control 3 weeks after treatment (WAT). However, 6 WAT, 2.6 to 3.4 kg ai/ha (2.3 to 3.0 lb ai/A) was required. Petri dish experiments were conducted to determine the aqueous concentrations of Gallery (isoxaben), Surflan (oryzalin), and Treflan required to control common nursery weeds including eclipta, hairy bittercress, large crabgrass and spotted spurge. The concentration required for 80% shoot inhibition (I80) ranged from 0.4 to 1.5 μg ai/mL for Gallery, 1.2 to 9.8 μg ai/mL for Surflan and 1.1 to 73.8 μg ai/mL for Treflan. The relative response of weeds to aqueous concentrations was consistent with reports from outdoor container efficacy trials.

GROWTH OF FOUR SOUTHWESTERN LANDSCAPE TREES IN CUPRIC-HYDROXIDE-PAINTED NURSERY CONTAINERS

Seedling liners of sweet acacia (Acacia smallii), shoestring acacia (Acacia stenophylla), palo brea (Cercidium praecox), and Chilean mesquite (Prosopis chilensis) were potted on 1 June 1993 into 27-liter (#5) black polyethylene containers filled with a 70% ponderosa pine forest mulch, 15% sand, and 15% silt (by volume) rooting medium. Just before potting, the inner wall of one-half of the containers of each species was painted with a latex paint impregnated with cupric hydroxide; the remaining containers were unpainted as a control treatment. Trees were then grown for 5 months in an outdoor container production nursery at a spacing distance of 45 cm. All trees were irrigated and fertilized according to standard nursery practices. The effect of cupric-hydroxide-painted containers (CHPC) on tree growth was species specific. Compared with nonpainted controls, CHPC caused roots to become more branched and decreased shoot lateral branch number and extension lengths of sweet acacia and shoestring acacia. CHPC also decreased height of shoestring acacia, but did not affect height of sweet acacia or root and shoot dry weight of sweet acacia and shoestring acacia. Shoot and root dry weight, height, and shoot lateral branch number and extension lengths of Chilean mesquite in CHPC were all increased compared with nonpainted controls. CHPC did not affect root branching of Chilean mesquite. Also, CHPC did not affect any measured growth variable of palo brea.