Horticultural Areas Research Articles

Using ladder entrance traps to capture azure-winged magpies, brown-eared bulbuls and black-billed magpies in Korea

Azure-winged magpies (AWMs, Cyanopica cyanus), brown-eared bulbuls (BEBs, Hypsipetes amaurotis) and black-billed magpies (BBMs, Pica pica) cause damage to trees, vines and soft fruits. We assessed the efficacy of modified ladder entrance (MLE) traps for the capture of these pest species in Korea. Using fruit bait and a ladder-entrance size of 9 × 9 cm, latency to capture was faster for AWM and BEB with live lure birds than without lure birds. AWM and BEB but not BBM were effective lure birds for either species. The trap with a 9 × 11 cm entrance size and baited with meat successfully removed BBM. They were caught only when the meat-baited traps were placed adjacent to roosting areas. The use of lure BBM birds did not reduce the latency to first capture of this species. The MLE trap is a useful tool for removing these three species of pest birds in horticultural areas of Korea when used with appropriate baits and entrance sizes, and using lure birds for AWMs and BEBs. Positioning of the traps is more important than the use of lure birds for the capture of BBMs.

Contesting the edge: analysing environmental decision-making as it is represented in the media

Media representations of environmental issues can provide insight into decision-making in complex contexts. Analysing different framings of an environmental problem can reveal the underlying biases and values that determine environmental decisions. This paper presents a case study of the conflict around proposed changes to the urban edge and its implications for the Philippi Horticultural Area in Cape Town, South Africa. An analysis of media representations of this contested environmental decision reveals the roles that framing, knowledge, power relations and public participation play in environmental decision-making. Drawing on principles of discourse analysis as a means of analysing the media, two opposing framings of the issue are described: ‘balancing complex needs to address housing and poverty’, and ‘Philippi, Cape Town's breadbasket’. Balancing the complexity of conflicting needs, supported by claims of expert, institutional knowledge characterise the framing adopted by decision-makers. In contrast, opponents emphasise food security concerns and scientific knowledge, and rely more heavily on the written policy than do decision-makers. These differing positions are upheld by separate groupings of actors, largely due to their dependence on very different knowledge bases. A lack of explicit acknowledgement of alternative frames and their associated value sets limits the possibility of effectively debating such issues, and of making effective and inclusive decisions in these complex policy situations.

Parasitoids of leafrollers (LepidopteraTortricidae) from scrub vegetation near horticultural areas in Nelson

Leafroller larvae and pupae were collected during timed searches in January and April 2013 from host plants at six scrub vegetation sites in two Nelson horticultural districts approximately 40 km apart The numbers of leafrollers and parasitoid species recovered were similar in both districts Most of the leafroller larvae collected were Epiphyas postvittana (Walker) (lightbrown apple moth LBAM) and most of these were found on gorse and broom In total 293 larvae and 11 pupae were reared successfully with 39 parasitism A wide diversity of parasitoids was recovered comprising 10 species from five families with Dolichogenidea tasmanica (Braconidae) the most common (80) The diversity of parasitoids and parasitism of leafrollers in unmanaged environments outside orchards may help to reduce leafroller pressure and the risk of fruit infestation in surrounding commercial orchards

Radiological Quality of Water in Areas with Old Uranium Mines in the District of Viseu, Portugal

Radionuclides were determined in streams and rivers receiving mine drainage in areas of old uranium mines at the centre of Portugal. Results showed enhanced radioactivity levels in some areas impacted by uranium mining and milling wastes, but lower than several years ago. Current treatment of mine drainage contributed to decrease radioactivity levels in streams. In some horticulture areas, such as at Cunha Baixa, water from irrigation wells was contaminated by acid mine drainage and is not suitable for human consumption and for irrigation. Villages and towns near those old uranium mines currently have tap water from public networks supplied from artificial lakes in major rivers of the region. This tap water showed compliance with the recommended limits of total alpha and total beta radioactivity and is suitable for human consumption.

시설 온실에서 진딧물에 대한 무인 연무방제기의 방제 효과 보고

The area of greenhouse horticulture has increased dramatically since the early 1990s in Korea. However, area per farmer still very small and diverse pest species occurs in greenhouse abundantly because of its protected condition. To manage pests, farmers use many pesticides frequently. Incessant and improper use of chemicals provoked pesticide resistance in pest and poisoning of farmers. In this study, we investigated the efficiencies of automatic dry fog sprayer for controlling two aphid species, Aphis gossypii and Myzus persicae, in greenhouse horticulture. When doors and side windows were completely closed in automatic dry fog sprayer treatment greenhouse, aphids were controlled similar level with conventional spraying method (percent control: 61.0~94.1%). However, when half of the doors and side windows of the greenhouse were opened, aphids were controlled poorly (percent control: 36.0~54.4%).

Heavy metals in the irrigation water, soils and vegetables in the Philippi horticultural area in the Western Cape Province of South Africa.

The aims of this study were to investigate the extent of heavy metal contamination in the Philippi horticultural area in the Western Cape Province, South Africa. Concentrations of Cd, Cr, Cu, Mn, Ni, Pb and Zn were determined in the irrigation water, soils and vegetables in both winter and summer cropping seasons with an ICP-AES and tested against certified standards. Differences were found in heavy metal concentrations between the winter and summer cropping seasons in the irrigation water, soils and vegetables. Certain heavy metals exceeded the maximum permissible concentrations in the irrigation water, soils and vegetables produced in South Africa. These toxic concentrations were predominantly found in the summer cropping season for the soils and in the crops produced in winter. It is thus suggested that further studies are carried out in the Philippi horticultural area to determine the sources of the heavy metals to try and mitigate the inputs thereof and therefore reduce the amount of heavy metals entering the human food chain.

Studies on the biology and occurrence of Ampelomyces quisqualis in the Drawski Landscape Park (NW Poland)

In the years 1996-1998, the ccurrence of <i>Ampelomyces quisqualis</i> parasitizing powdery mildews (<i>Erysiphales</i>) affecting plants of 12 permanent plots with nine plant assciations, as well as those of 32 agricultural fields and gardens of the Drawsko Landscape Park in north-western Poland was investigated. The plant associations of the 12 permanent plots were <i>Luzulo pilosae-Fagetum, Stellrio-Carpinetum, Querco roboris-Pinetum, Leucobryo-Pinetum, Ribo nigri-Alnenun, Circaeo-Alnetum, Vaccino ulginosi-Pinetum, Chenopodietea</i>, and <i>Artemisietea</i>. In the laboratory, the morphology of this hyperparasite, its pattern of colonization of powdery mildews as well as the influence of cultural conditions on its growth and sporulation were determined. Of the 57 species of <i>Erysiphales</i> found in Drawsko Landscape Park, <i>A. quisqualis</i> parasitized 14 in three genera. Of them, nine species were for the first time found to be fungal hosts of <i>A. quisqualis</i> in Poland. This hyperparasite preferred the <i>Artemisietea</i> and <i>Chenopodiatea</i> plant associations, as well as plants of agricultural and horticultural areas, i. e., plants of warmer sites compared with the others considered in this study. The media favouring the growth and sporulation of <i>A. quisqualis</i> were Sabouraud agar and potato dextrose agar. The optimal temperature range for both growth and sporulation of <i>A. quisqualis</i> was 20 -25°C.

Influence of colonization by arbuscular mycorrhizal fungi on three strawberry cultivars under salty conditions

Plant adaptation to hyperosmotic environments is generally associated with reduced growth and ultimately yield loss, making farming difficult. The potential of mycorrhizal symbioses to alleviate salt stress has been documented and benefits to plant revealed to be specific and dependent to both plant cultivars and fungal strains. A factorial greenhouse experiment was performed to determine the effects of three arbuscular mycorrhizal fungi (AMF) species (Funneliformis caledonius, F. mosseae and Rhizophagus irregularis) on three ‘day-neutral’ strawberry (Fragaria × ananassa Duch.) cultivars (‘Albion’, ‘Charlotte’ and ‘Seascape’), and a mixture of R. irregularis and F. mosseae on ‘Seascape’, under four salt conditions (0–200 mM NaCl). The overall results showed that plant biomass decreased with increasing salinity. The cultivars responded differently to both AMF and salinity, and ‘Seascape’ was more tolerant to salinity than the other cultivars. AMF enhanced plant growth and improved salt tolerance by increasing the proportion of medium (0.5<ɸ≤1.5 mm) and coarse (ɸ>1.5 mm) diameter roots. The mixture of two AMF species increased root and shoot mass to a higher degree than each species alone at low salinity (0–50 mM) but reduced fruit quality. At higher levels (100–200 mM), R. irregularis alleviated salt stress and improved fruit quality to a higher degree than the other AMF species. Our results support the use of bio-inoculants in saline horticultural areas. Because cultivars respond differently to fungal inoculants, and inoculants prefer specific environmental conditions, fungal inoculants need to be screened on a cultivar- and condition-specific basis.

Podridão apical e escaldadura em frutos de pimentão submetidos a estresse hídrico e doses de silício

As respostas da planta de pimentão submetida ao estresse hídrico são pouco conhecidas. A busca por indutores de resistência ao estresse hídrico (como a adubação silicatada) pode ser uma importante medida para reduzir os efeitos negativos desse estresse abiótico. Dessa forma, o objetivo desse estudo foi testar a hipótese de que a adubação silicatada aplicada via foliar pode atenuar a incidência de anomalias causadas pelo estresse hídrico na qualidade dos frutos de pimentão. O experimento foi conduzido em ambiente protegido na área experimental de olericultura do Instituto Federal Goiano, câmpus Urutaí-GO. O delineamento utilizado foi em blocos casualizados, com parcela subdividida no espaço, em esquema fatorial 3x4, sendo três doses de silício (0,0, 4,3, 8,6 kg ha-1) na forma de silicato de potássio (K2SiO3) e quatro tensões de água no solo de aproximadamente -15, -25, -35 e -45 kPa, totalizando 12 tratamentos, com quatro repetições. Os níveis de água no solo para a produção do pimentão, cultivar híbrido Magali-R, variaram desde a suficiente oferta de água até o déficit hídrico e, também, valores intermediários. Vinte e uma aplicações foliares de silicato de potássio foram efetuadas semanalmente ao longo do experimento. O aumento da tensão de água no solo e a ausência do silicato de potássio estiveram correlacionados com a incidência da podridão apical nos frutos. Nenhum dos dois fatores estudados influenciou a incidência de escaldadura nos frutos de pimentão. No total foram 129 frutos de pimentão com podridão apical e 70 com escaldadura, representando 2,14% e 1,16% do total de frutos colhidos.

Distribution and abundance of human-specific Bacteroides and relation to traditional indicators in an urban tropical catchment.

AimsThe study goals were to determine the relationship between faecal indicator bacteria (FIB), the HF183 marker and land use, and the phylogenetic diversity of HF183 marker sequences in a tropical urban watershed.Methods and ResultsTotal coliforms, Escherichia coli, and HF183 were quantified in 81 samples categorized as undeveloped, residential and horticultural from the Kranji Reservoir and Catchment in Singapore. Quantitative-PCR for HF183 followed by analysis of variance indicated that horticultural areas had significantly higher geometric means for marker levels (4·3 × 104 HF183-GE 100 ml−1) than nonhorticultural areas (3·07 × 103 HF183-GE 100 ml−1). E. coli and HF183 were moderately correlated in horticultural areas (R = 0·59, P = 0·0077), but not elsewhere in the catchment. Initial upstream surveys of candidate sources revealed elevated HF183 in a wastewater treatment effluent but not in aquaculture ponds. The HF183 marker was cloned, sequenced and determined by phylogenetic analysis to match the original marker description.ConclusionWe show that quantification of the HF183 marker is a useful tool for mapping the spatial distribution and potential sources of human sewage contamination in tropical environments such as Singapore.Significance and ImpactA major challenge for assessment of water quality in tropical environments is the natural occurrence and nonconservative behaviour of FIB. The HF183 marker has been employed in temperate environments as an alternative indicator for human sewage contamination. Our study supports the use of the HF183 marker as an indicator for human sewage in Singapore and motivates further work to determine HF183 marker levels that correspond to public health risk in tropical environments.

Effect of a Passive Mixing Device on the Electrical Conductivity and pH Values of a Nutrient Solution

AbstractThe adjustment of a nutrient solution using an automated fertigation system for optimal irrigation conditions increases productivity and decreases the environmental impact of horticulture. A new generation of infrastructure for automated solution preparation is becoming more common in high-technological protected horticultural areas; for example, the direct injection of all components into the nutrient solution using a Venturi device on the irrigation headpiece is being widely used. The present study evaluates the utility of a passive mixing device that was incorporated into the circuit of the fertigation headpiece and its impact on parameters such as the electric conductivity (EC) and pH of the nutrient solution. The results suggest two important effects, as follows: (1) the device helps in the adjustment of the EC and pH in the nutrient solution, compared with values set during programming, and (2) there is a lower variation in the dispersion between the maximum and minimum values.

Spatial and seasonal variations of pesticide contamination in agricultural soils and crops sample from an intensive horticulture area of Hohhot, North-West China

The spatial variability and temporal trend in concentrations of the organochlorine pesticides (OCPs), hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), in soils and agricultural corps were investigated on an intensive horticulture area in Hohhot, North-West China, from 2008 to 2011. The most frequently found and abundant pesticides were the metabolites of DDT (p,p'-DDE, p,p'-DDT, o,p'-DDT and p,p'-DDD). Total DDT concentrations ranged from ND (not detectable) to 507.41 ng/g and were higher than the concentration of total HCHs measured for the range of 4.84-281.44 ng/g. There were significantly positive correlations between the ∑DDT and ∑HCH concentrations (r (2)>0.74) in soils, but no significant correlation was found between the concentrations of OCPs in soils and clay content while a relatively strong correlation was found between total OCP concentrations and total organic carbon (TOC). β-HCH was the main isomer of HCHs, and was detected in all samples; the maximum proportion of β-HCH compared to ∑HCHs (mean value 54%) was found, suggesting its persistence. The α/γ-HCH ratio was between 0.89 and 5.39, which signified the combined influence of technical HCHs and lindane. Low p,p'-DDE/p,p'-DDT in N1, N3 and N9 were found, reflecting the fresh input of DDTs, while the relatively high o,p'-DDT/p,p'-DDT ratios indicated the agricultural application of dicofol. Ratios of DDT/(DDE+DDD) in soils do not indicate recent inputs of DDT into Hohhot farmland soil environment. Seasonal variations of OCPs featured higher concentrations in autumn and lower concentrations in spring. This was likely associated with their temperature-driven re-volatilization and application of dicofol in late spring.

Conspecific and heterospecific interactions between two omnivorous predators on tomato

Antagonistic interactions among invertebrate predators such as intraguild predation and cannibalism have the potential to dampen top-down impacts on shared prey. Two abundant heteropteran predators, Macrolophus pygmaeus (Rambur) and Nesidiocoris tenuis Reuter co-occur in the tomato crops of the Mediterranean horticultural area where they both attack whiteflies and lepidoptera, the dominant herbivores in the crop. Experiments in the laboratory were used to assess the incidence of intraguild predation and cannibalism in these predators. The effects of these interactions on survivorship, progeny and within-plant distributions were studied, as well as the effect of the presence of M. pygmaeus on the damage caused by N. tenuis to tomato plants. When predators of different stages coexisted, only the mortality of M. pygmaeus second-third instar nymphs caused by N. tenuis adult females was observed. When predators of the same stage (second-third instar nymphs or adult females) coexisted, mortality caused by IGP and cannibalism was observed only between adult females and usually associated to the absence of additional prey. When adult females coexisted without additional prey, the progeny of both predator species were reduced, showing a relationship only with the density and not with the presence of other predator species. However, when additional prey was offered, only M. pygmaeus progeny were reduced, showing a higher capacity of N. tenuis to maintain their reproductive potential at high densities. When both predator species coexisted, N. tenuis adult females caused more damage to tomato plants, suggesting that their coexistence could affect the crop. The consequences of conspecific and heterospecific interactions of M. pygmaeus and N. tenuis are discussed for the biological control of whiteflies and other tomato pests.

Water Quality Characterization in the Northern Florida Everglades

The Loxahatchee National Wildlife Refuge (Refuge) developed as a system with waters low in nutrients. Today, the Refuge wetlands are impacted by inflows containing elevated nutrient concentrations originating from agricultural sources flowing into canals surrounding the west side and from urban and horticultural areas flowing into canals surrounding the eastern side of the Refuge. We analyzed water quality sampled at 40 sites divided into eastern and western areas and four zones in the Refuge. We defined four zones as the canals surrounding the Refuge marsh, the perimeter zone, the transition zone, and the interior zone. The canal receiving agricultural inflows had greater alkalinity and conductivity (SpC), Si and SO4 but lower turbidity and total suspended solids than the canal receiving urban and horticultural inflows. Alkalinity, total dissolved solids (TDS), SpC, Ca, Cl, and SO4 concentrations were greater in the perimeter than in transition and interior zones. Alkalinity and SpC values and SO4 concentrations were greater in the transition than in interior zone. Alkalinity, SpC, and TDS values and Ca, SO4, and Cl concentrations correlated in negative curvilinear relationships with distance from the canal (r2 = 0.78, 0.70, 0.61, 0.78, 0.64, 0.57, respectively). Analysis of multiple water quality parameters may reveal the complexity of interactions that might be overlooked in a simple single parameter analysis. These data show an impact of canal water containing high nutrient concentrations on water quality flowing from the canal towards the Refuge interior.

Impact of intensive horticulture practices on groundwater content of nitrates, sodium, potassium, and pesticides

A monitoring program of nitrate, nitrite, potassium, sodium, and pesticides was carried out in water samples from an intensive horticulture area in a vulnerable zone from north of Portugal. Eight collecting points were selected and water-analyzed in five sampling campaigns, during 1 year. Chemometric techniques, such as cluster analysis, principal component analysis (PCA), and discriminant analysis, were used in order to understand the impact of intensive horticulture practices on dug and drilled wells groundwater and to study variations in the hydrochemistry of groundwater. PCA performed on pesticide data matrix yielded seven significant PCs explaining 77.67% of the data variance. Although PCA rendered considerable data reduction, it could not clearly group and distinguish the sample types. However, a visible differentiation between the water samples was obtained. Cluster and discriminant analysis grouped the eight collecting points into three clusters of similar characteristics pertaining to water contamination, indicating that it is necessary to improve the use of water, fertilizers, and pesticides. Inorganic fertilizers such as potassium nitrate were suspected to be the most important factors for nitrate contamination since highly significant Pearson correlation (r = 0.691, P < 0.01) was obtained between groundwater nitrate and potassium contents. Water from dug wells is especially prone to contamination from the grower and their closer neighbor's practices. Water from drilled wells is also contaminated from distant practices.

Fall Panicum: Biology and Control in Sugarcane

Fall panicum (Panicum dichotomiflorum) is a native grass that can be found throughout the United States in agronomic and horticultural crops, turfgrass, nurseries, landscapes, and noncrop areas. It grows well in warm wet conditions and is one of the most common grass weeds found in Florida sugarcane. This 3-page fact sheet provides sugarcane growers with guidance on its identification and control. Written by D.C. Odero, Brent Sellers, Les Baucum, and Curtis Rainbolt, and published by the UF Department of Agronomy, May 2011. SS-AGR-132/SC079: Fall Panicum: Biology and Control in Sugarcane (ufl.edu)

A GIS Framework for Changing Cropping Pattern Under Different Climate Conditions and Irrigation Availability Scenarios

Irrigation water availability is a main driver which determines cropping patterns for an irrigation area. Irrigation water availability will potentially reduce due to changes in climate and irrigation extraction limits. Cropping patterns should be adjusted to meet this challenge. This study presents a new approach for assessing future cropping patterns using GIS in combination with an Irrigation Water Availability Simulation model (IWAS) at irrigation area scale. The IWAS-GIS framework was developed for analysis of cropping pattern options based on the forecast of irrigation water availability in 2030 for the Murrumbidgee Irrigation Area (MIA) which is one of the most important irrigation areas in Australia. Six scenarios considering climatic conditions and the irrigation availabilities were input into the IWAS-GIS framework to simulate cropping pattern changes corresponding to predicted monthly irrigation water availability. Cropping patterns were designed by integration of soil type and irrigation water availability to improve irrigation sustainability. Simulations results indicate that the total irrigated areas will likely decrease with drier climate and less irrigation availability. Rice and pasture areas change significantly when climate and irrigation availability varies. Under the same climate condition, horticulture area increases when irrigation availability decrease. The percentage of lands which are unsuitable for cropping has reduced with the drying climate and shrinking irrigation availability. The IWAS-GIS is simple to implement and provides an easy way for assessing spatial cropping pattern changes based on irrigation water availability. This framework was developed to help irrigators plan cropping patterns corresponding to irrigation water availability. It is flexible to be adopted for similar applications in other irrigation areas.

Germinação de sementes de Conyza canadensis e Conyza bonariensis em diferentes condições de temperatura e luminosidade

A buva (Conyza canadensis e C. bonariensis) é uma planta daninha de importância crescente no Brasil. Essas espécies ocorrem em diversas regiões do mundo, sendo importantes infestantes de culturas perenes e anuais sob sistema de semeadura direta, cultivo mínimo e áreas de fruticultura. Neste trabalho, foi estudado o efeito de temperaturas constantes na germinação de sementes das duas espécies, por meio de dois experimentos realizados em câmaras de germinação com temperaturas constantes e 12 horas diárias de luz. A unidade experimental foi constituída por caixas de acrílico transparente com 50 sementes, dispostas sobre duas folhas de papel mata-borrão umedecidas com água destilada. No primeiro experimento, foi estudado o comportamento germinativo das espécies nas temperaturas constantes de 15, 20, 25, 30, 35 e 40 ºC. Já no segundo, estudou-se o comportamento germinativo das espécies sob condições de temperaturas constantes (20, 25 e 30 ºC) na ausência/presença de luz (12 horas diárias), além de um tratamento adicional sobre a bancada do laboratório. A germinação e a velocidade de germinação foram superiores nas temperaturas de 20 e 25 ºC, para as duas espécies em estudo. A germinação nas temperaturas de 15, 35 e 40 ºC foi reduzida significativamente. As espécies comportam-se como fotoblásticas positivas.

Characterization of technological levels in Mediterranean horticultural greenhouses

The technology existing in Spanish horticultural greenhouses is highly diverse; however, low levels predominate. Therefore urgent improvements and conversions are required to increase yields and quality to maintain competitive production. To define the equipment and investment required, it is necessary to establish the current levels of technology and the extent to which it is developing. To do so, information has been collected using a survey based on stratified random sampling in the three most important greenhouse horticultural areas in Spain: Almería, Murcia and Southern Alicante. Based on information from 242 farms, five groups of technological levels with a gradual variation in technology were identified by cluster analysis. Of the five groups, three relate to cultivation in soil and the other two to soilless culture. In this study, we have applied the test for independence in order to relate the levels obtained with certain relevant characteristics of the farm. The results display the usefulness of grouping the greenhouses by levels, and reveal which are the most characteristic components in level formation with their percentage distribution. Thus, current characteristics of technology, and its development, have been identified, and priority assigned to the different components.

Presence of the Aphid,Chaetosiphon fragaefolii, on Strawberry in Argentina

Seasonal abundance of the strawberry aphid complex under different agronomic practices in the outskirts of La Plata, Argentina was studied on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae). Aphid densities were low in strawberry fields in which insecticides and fungicides were used. In addition to Aphis gossypii, Aphis fabae, Mysus persicae and Macrosiphum euphorbiae, the aphid, Chaetosiphon fragaefolii (Cockerell) (Homoptera: Aphididae), was recorded for the first time in this horticultural area. Life history and some demographic parameters were calculated for C. fragaefolii. The mean duration of nymphal stages was 10.44 days, the oviposition period was 11.8 days, and the mean number of nymph/female/day was 2.4 ± 0.3. Demographic parameters analyzed included the net reproductive rate Ro = 14.55 ± 0.096 nymph/female, generation time T=16.91 ± 0.035 days, and the intrinsic rate of increase rm = 0.158 ± (0.004). No parasites were found associated with C. fragaefolli. The pathogenic fungus, Entomophthora planchoniana Cornu (Zygomycetes: Entomophthorales) was the main mortality factor. Although aphids are not the main pests in strawberry fields, C. fragaefolii can be a serious problem because it can transmit several virus diseases of strawberry. Greater knowledge of life history traits and mortality factors of this species is needed in order to design appropriate control strategies.