Commercial Plant Nurseries Research Articles

Phytophthora spp. diversity in commercial nursery stocks shown through examination of plant health practices for growers and traders of ornamental plants

Management of Phytophthora in commercial plant nurseries is important for biosecurity of traded plants, and monitoring of incidence of this important plant pathogen is a prerequisite to prevent its spread. Potted plants showing Phytophthora spp. symptoms, and nursery irrigation and runoff water, were sampled from a commercial and a non-commercial nursery in Tuscany, Italy. The samples were processed to detect Phytophthora spp., using baiting, and molecular identification of obtained isolates. High Phytophthora incidence was shown in the commercial nursery. Twelve Phytophthora spp. were isolated from potted plants or nursery runoff water. Individual symptomatic potted plants were infected with up to four pathogenic Phytophthora spp. The water sampled from nursery drainage canals had the greatest Phytophthora species diversity, with less diversity in ‘flow-through’ water samples (irrigation water percolated through potted plants) and samples from water puddles inside the nurseries. This study showed high incidence of Phytophthora in the commercial nursery, and associated risk of spread of these pathogens within and outside nursery operations. Lack of appropriate disease management probably increases occurrence of these pathogens.

Pesticides as a potential independent childhood leukemia risk factor and as a potential confounder for electromagnetic fields exposure

BackgroundBoth pesticides and high magnetic fields are suspected to be childhood leukemia risk factors. Pesticides are utilized at commercial plant nurseries, which sometimes occupy the areas underneath high-voltage powerlines. ObjectivesTo evaluate whether potential pesticide exposures (intended use, chemical class, active ingredient) utilized at plant nurseries act as an independent childhood leukemia risk factor or as a confounder for proximity to, or magnetic fields exposure from, high-voltage powerlines. MethodsWe conducted a state-wide records-based case-control study for California with 5788 childhood leukemia cases and 5788 controls that examined specific pesticide use, magnetic field exposures and distances to both powerlines and plant nurseries. Exposure assessment incorporated geographic information systems, aerial satellite images, and other historical information. ResultsChildhood leukemia risk was potentially elevated for several active pesticide ingredients: permethrin (odds ratio (OR) 1.49, 95% confidence interval (CI) (0.83–2.67), chlorpyrifos (OR 1.29, 95% CI 0.89–1.87), dimethoate (OR 1.79, 95% CI 0.85–3.76), mancozeb (OR 1.41, 95% CI 0.85–2.33), oxyfluorfen (OR 1.41, 95% CI 0.75–2.66), oryzalin (OR 1.60, 95% CI 0.97–2.63), and pendimethalin (OR 1.82, 95% CI 0.81–2.25). Rodenticide (OR 1.42, 95% CI 0.78–2.56) and molluscicide (OR 1.22, 95% CI 0.82–1.81) exposure also presented potentially elevated childhood leukemia risks. Childhood leukemia associations with calculated fields or powerline proximity did not materially change after adjusting for pesticide exposure. Childhood leukemia risks with powerline proximity remained similar when pesticide exposures were excluded. DiscussionPesticide exposure may be an independent childhood leukemia risk factor. Childhood leukemia risks for powerline proximity and magnetic fields exposure were not explained by pesticide exposure.

Commercial outdoor plant nurseries as a confounder for electromagnetic fields and childhood leukemia risk.

BackgroundClose residential proximity to powerlines and high magnetic fields exposure may be associated with elevated childhood leukemia risks as reported by prior studies and pooled analyses. Magnetic fields exposure from high-voltage powerlines is associated with proximity to these powerlines and consequently with any factor varying with distance. Areas underneath powerlines in California may be sites for commercial plant nurseries that can use pesticides, a potential childhood leukemia risk factor. ObjectivesAssess if potential pesticide exposure from commercial plant nurseries is a confounder or interacts with proximity or magnetic fields exposure from high-voltage powerlines to increase childhood leukemia risk. MethodsA comprehensive childhood leukemia record-based case-control study with 5788 cases and 5788 controls (born and diagnosed in California, 1986–2008) was conducted. Pesticide, powerline, and magnetic field exposure assessment utilized models that incorporated geographical information systems, aerial satellite images, site visits and other historical information. ResultsThe relationship for calculated fields with childhood leukemia (odds ratio (OR) 1.51, 95% confidence interval (CI) 0.70–3.23) slightly attenuated when controlling for nursery proximity (OR 1.43, 95% CI 0.65–3.16) or restricting analysis to subjects living far (>300 m) from nurseries (OR 1.43, 95% CI 0.79–2.60). A similar association pattern was observed between distance to high-voltage powerlines and childhood leukemia. The association between nursery proximity and childhood leukemia was unchanged or only slightly attenuated when controlling for calculated fields or powerline distance; ORs remained above 2 when excluding subjects with high calculated fields or close powerline proximity (OR 2.16, 95% CI 0.82–5.67 and OR 2.15, 95% CI 0.82–5.64, respectively). The observed relationships were robust to different time periods, reference categories, and cut points. DiscussionClose residential proximity to nurseries is suggested as an independent childhood leukemia risk factor. Our results do not support plant nurseries as an explanation for observed childhood leukemia risks for powerline proximity and magnetic fields exposure, although small numbers of subjects concurrently exposed to high magnetic fields, close powerline proximity and plant nurseries limited our ability to fully assess potential confounding.

Diversity and turnover of wild bee and ornamental plant assemblages in commercial plant nurseries

In human-modified landscapes, understanding how habitat characteristics influence the diversity and composition of beneficial organisms is critical to conservation efforts and modeling ecosystem services. Assessing turnover, or the magnitude of change in species composition across sites or through time, is crucial to said efforts, yet is often overlooked. For pollinators such as wild bees, variables influencing temporal turnover, particularly across seasons within a year, remain poorly understood. To investigate how local and landscape characteristics correlate with bee diversity and turnover across seasons, we recorded wild bee and flowering ornamental plant assemblages at 13 plant nurseries in California between spring and autumn over 2 years. Nurseries cultivate a broad diversity of flowering plant species that differ widely across sites and seasons, providing an opportunity to test for correlations between turnover and diversity of plants and bees. As expected, we documented strong seasonal trends in wild bee diversity and composition. We found that local habitat factors, such as increased cultivation of native plants, were positively associated with bee diversity in sweep netting collections, whereas we detected moderate influences of landscape level factors such as proportion of surrounding natural area in passive trap collections. We also detected a moderate positive correlation between the magnitude of turnover in plant species and that of bee species (as number of taxa gained) across consecutive seasons. Our results have implications for the conservation of wild bees in ornamental plant landscapes, and highlight the utility of plant nurseries for investigating hypotheses related to diversity and turnover in plant-pollinator systems.

Update on the occurrence and dispersion of the Achatina (Lissachatina) fulica Bowdich, 1822 (Mollusca, Gastropoda) snail within the Federal District, Brazil

Achatina (Lissachatina) fulica is present in most Brazilian States. This paper aims at providing a diagnosis of the occurrence and dispersion of A. fulica in the Distrito Federal. Pages and posts for social medias were created to identify areas of A. fulica occurrences. In addition, interviews and active searches at commercial plant nurseries were undertaken. Collection took place from March 2019 to February 2020 and January 2021. The sampled areas were categorized into commercial nurseries, Paranoá Lake shore, other urban areas, and agricultural areas. Commercial nurseries were identified as the main sources of A. fulica in the Distrito Federal

The potential influence of commercial plant nurseries in shaping the urban forest in South Africa

A substantial portion of urban green infrastructure is under private tenure in residents’ and business/corporate gardens. Therefore, the ways that urban residents manage their gardens can influence the type, quantity and quality of ecosystem services and disservices in urban areas. Plant nurseries are a major source of trees for urban residents, and so the types of trees and species that nurseries stock influence the composition of private gardens. Consequently, this study aimed to examine the roles that plant nurseries play in shaping the urban forest in South Africa. To do so, an online and direct questionnaire was used to gather data from 30 nurseries across 19 urban centres in South Africa. The main questions included species selection criteria, customer tree inquiries, best-selling tree species, attitudes towards increasing urban tree cover and diversity and whether they think climate change will affect the selection of species to stock. The results show that there is a strong preference for indigenous trees, which were also most commonly listed as best-sellers. Non-native species that were commonly sold were ones that provided provisioning services, particularly edible fruits. Drought tolerance influenced selection criteria and customer demand. Vachellia spp. and Olea europaea were commonly inquired about and most commonly listed amongst the best-sellers. Nursery owners valued the importance of increasing tree cover and diversity in urban areas, listing many perceived benefits for doing so. We conclude that there is a clear preference for indigenous tree species by customers and nursery owners, which in time could increase the proportion and cover of native species.

Residential proximity to plant nurseries and risk of childhood leukemia

BackgroundPesticides are a potential risk factor for childhood leukemia. Studies evaluating the role of prenatal and/or early life exposure to pesticides in the development of childhood leukemia have produced a range of results. In addition to indoor use of pesticides, higher risks have been reported for children born near agricultural crops. No studies have looked at pesticide exposure based on proximity of birth residence to commercial plant nurseries, even though nurseries are located much closer to residences than agricultural crops and can potentially result in chronic year-round pesticide exposure. ObjectivesTo evaluate whether risk of childhood leukemia is associated with pesticide use as determined by distance of residence at birth to commercial, outdoor plant nurseries. MethodsWe conducted a large statewide, record-based case-control study of childhood leukemia in California, which included 5788 childhood leukemia cases and an equal number of controls. Pesticide exposure was based on a spatial proximity model, which combined geographic information system data with aerial satellite imagery. ResultsOverall, the results supported an increased childhood leukemia risk only for birth residences very close to nurseries. For birth residences less than 75 m from plant nurseries, we found an increased risk of childhood leukemia (odds ratio (OR) 2.40, 95% confidence interval (CI) 0.99-5.82) that was stronger for acute lymphocytic leukemia (OR 3.09, 95% CI 1.14-8.34). DiscussionThe association was robust to choices of reference group, cut points and data quality. Our findings suggest that close proximity to plant nurseries may be a risk factor for childhood leukemia and that this relationship should be further evaluated.

Land slugs in plant nurseries, a potential cause of dispersal in Argentina

Commercial plant nurseries may serve as causes of dispersal of land snails and slugs (native and non-native) through the trade of plants and the related transport of eggs and small individuals that may pass unnoticed. Studies on the possible role of plant nurseries as a potential cause of dispersal of slugs in South America are lacking. To explore the role of garden centers, we collected and identified slugs in 12 commercial nurseries in two cities in the province of Buenos Aires, Argentina. Eight species of slugs were found. Based on our findings we validate the existence of Deroceras laeve and Belocaulus angustipes for Argentina and confirm the existence of Ambigolimax valentianus, which was recently cited for Argentina. We recommend that plant nurseries be regularly monitored given that snail and slug species are accidentally spread through trade in plants. Dataset published through Zenodo (Doi: http://doi.org/10.5281/zenodo.4304621)

Role of Trichoderma aggressivum f. europaeum as Plant-Growth Promoter in Horticulture

The main objective of this study was to determine the capacity of Trichoderma aggressivum f. europaeum to promote pepper and tomato seedling growth compared to that of T. saturnisporum, a species recently characterised as a biostimulant. Consequently, in vitro seed germination and seedling growth tests were performed under commercial plant nursery conditions. Additionally, the effects of different doses and a mixture of both species on seedling growth under plant nursery and subsequently under greenhouse conditions were determined. Furthermore, mass production of spores was determined in different substrates, and their siderophore and indole acetic acid production and phosphate (P) solubilisation capacity were also determined. Direct application of Trichoderma aggressivum f. europaeum to seeds in vitro neither increases the percentage of pepper and tomato seed germination nor improves their vigour index. However, substrate irrigation using different doses under commercial plant nursery conditions increases the quality of tomato and pepper seedlings. Tomato roots increased by 66.66% at doses of 106 spores per plant. Applying T. aggressivum f. europaeum or T. saturnisporum under plant nursery conditions added value to seedlings because their growth-promoting effect is maintained under greenhouse conditions up to three months after transplantation. The combined application of the two species had no beneficial effect in relation to that of the control. The present study demonstrates the biostimulant capacity of T. aggressivum f. europaeum in pepper and tomato plants under commercial plant nursery and greenhouse conditions.

Phytophthora Species Associated with Plants in Constructed Wetlands and Vegetated Channels at a Commercial Plant Nursery Over Time

Constructed wetlands have been used for decades in agricultural settings to remediate nutrients and other agrichemicals from irrigation runoff and drainage; however, little is known about the presence and distribution of Phytophthora species within irrigation runoff water being treated in constructed wetlands. Therefore, we collected plant samples from within vegetated runoff collection channels and treatment stages of two constructed wetland systems receiving irrigation runoff at a commercial plant nursery in Cairo, GA, to determine if roots of wetland plants were infested by species of Phytophthora. Samples were collected 12 times, at 1- to 2-month intervals, over a 19-month period, from Mar. 2011 through Sept. 2012. The sample period covered all four seasons of the year, so we could determine if the association of Phytophthora species with roots of specific plant species varied with season. Approximately 340 samples from 14 wetland plant species were collected, and 22 isolates of Phytophthora species were recovered. Phytophthora species were typically isolated from plants in channels receiving runoff water directly from plant production areas; Phytophthora species were not detected on plants where water leaves the nursery. No seasonal patterns were observed in plant infestation or presence of species of Phytophthora. In fact, Phytophthora species were rarely found to be associated with the roots of the wetland plants collected; species of Phytophthora were found infesting roots of only 6.5% of the 336 plants sampled. Species of Phytophthora were not found to be associated with the roots of golden canna (Canna flaccida), lamp rush (Juncus effusus var. solutus), duckweed (Lemna valdiviana), or sedges (Carex sp.) during the study period. The exotic invasive plant species marsh dayflower [Murdannia keisak (33% of samples infested)] and alligatorweed [Alternanthera philoxeroides (15% of samples infested)] were found to have the first and third highest, respectively, incidences of infestation, with smooth beggartick (Bidens laevis) having the second highest incidence of samples infested (22%). Management of invasive species in drainage canals and constructed wetland systems may be critical because of their potential propensity toward infestation by Phytophthora species. Plant species recommended for further investigation for use in constructed wetlands to remediate irrigation runoff include golden canna, marsh pennywort (Hydrocotyle umbellata), pickerelweed (Pontederia cordata), and broadleaf cattail (Typha latifolia). The results from this study provide an important first look at the associations between species of Phytophthora and wetland plants in constructed wetland systems treating irrigation runoff and will serve to further optimize the design of constructed wetlands and other vegetation-based treatment technologies for the removal of plant pathogens from irrigation runoff.

Genetic diversity and molecular fingerprinting of Prunus cerasus var. austera from central Italy

In central Italy, Prunus cerasus var. austera is cultivated as small stands or scattered trees in marginal areas for the production of jam and wine. Thanks to the healthy attributes of its products and its ability to grow in different environmental conditions, this variety has gained new interest in the development of marginal areas. We assessed the level of the genetic variability of P. cerasus var. austera germplasm from central Italy and identified a ‘core collection’ representative of the present genetic diversity. A total of 161 trees, morphologically identified as var. austera, and one tree, identified as var. caproniana were collected and genotyped by 14 SSRs. Two individuals provided by a commercial plant nursery, one of P. cerasus var. caproniana and one of P. cerasus var. austera, were used as control. Thirteen SSRs presented private alleles in austera. Seven individuals morphologically identified as austera revealed private alleles specific to caproniana. The PCoA and Bayesian clustering analysis showed a main genetic group including var. austera, while a second group included all the caproniana-like genotypes. A core collection of 31 trees (46% of austera genotypes) was selected. This study can be considered as a starting point for future investigations on this variety.

Biodiversity, biosecurity and integrated pest management

Breaches of biosecurity, leading to incursions by invasive species, have the potential to cause substantial economic, social and environmental losses, including drastic reduction in biodiversity. It is argued that improving biosecurity reduces risk to biodiversity, while maintaining stable ecosystems through biodiversity can be a safeguard against biosecurity breaches. The global costs of invasive alien species (IAS) have been estimated at around US$350 billion, while alien invertebrate and vertebrate pests and weeds are estimated to cost Australia at least $7 billion a year. A striking, current, example is the incursion by Myrtle Rust (Puccinia psidii) an organism which can infect all members of the Myrtaceae, the most important family in the Australian flora. Myrtle rust was first detected on a property on the central coast of New South Wales in late April 2010. Two years later the disease has been detected in numerous locations in Queensland and New South Wales ranging from commercial plant nurseries and public amenities to large areas of bushland. This particular breach of biosecurity will, inevitably, diminish biodiversity of flora and fauna over large areas of the continent. Integrated pest management (IPM), an enrichment of diversity in managing invasive and other pest species, offers the best opportunity to address problems such as these. Australia's response to increasing biosecurity risk is comprehensive and includes national networking of scientists engaged in a complex program of biosecurity research and development, including studies of IPM. This network is being enhanced by the development of international linkages.

A comparative cost analysis for using compost derived from anaerobic digestion as a peat substitute in a commercial plant nursery

A.P. Restrepo, J. Garcia-Garcia, R. Moral, F. Vidal, M.D. Perez-Murcia, M.A. Bustamante y C. Paredes. 2013. Analisis de costes comparativo del uso de compost derivados de procesos de biometanizacion en sustitucion de turbas en semilleros horticolas comerciales. Cien. Inv. Agr. 40(2): 253-264. El objeto del presente estudio fue evaluar la viabilidad economica de compost derivados de la biometanizacion de estiercoles vacunos en su uso en semilleros horticolas comerciales. Mediante un analisis comparativo se ensayaron dosis crecientes de sustitucion compost-turba (25, 50 y 75%, expresado en volumen), frente al medio de turba comercial. Se pretende establecer las condiciones en las que el uso del compost propuesto es viable y competitivo frente al uso de turbas comerciales, tanto a nivel agronomico como economico. Se establece como condicion necesaria en las estrategias de sustitucion la inexistencia de disminucion de la calidad de la germinacion y del desarrollo vegetativo de las plantulas de los cultivos seleccionados para el ensayo (tomate, melon y pimiento). Tambien se ha cuantificado el efecto economico que tendria en una explotacion comercial representativa el uso del sustrato alternativo mezcla, frente al uso exclusivo de turbas que actualmente se realiza. Como principales resultados se ha obtenido que el escenario mas idoneo a nivel agronomico se situa en el 25% de sustitucion de la turba, siendo mas limitante tasas de sustitucion superiores, especialmente para el cultivo de tomate. A nivel economico se pueden alcanzar reducciones de hasta el 43% del coste del sustrato con un incremento de hasta un 4,6% del margen bruto comercial de una empresa tipo para la sustitucion de turba en un 50%.

Plant pathogens in recycled irrigation water in commercial plant nurseries and greenhouses: their detection and management

With water conservation and reuse a priority for communities worldwide, recycling irrigation water in commercial plant nurseries and greenhouses is a logical measure. Plant pathogenic microorganisms may be present in the initial water source, or may accrue and disperse from various points throughout the irrigation system, constituting a risk of disease to irrigated plants. The continual recycling of this water is exacerbating this plant disease risk. Accurate and timely detection of plant pathogenic propagules in recycled irrigation water is required to assess disease risk. Both biological and economic thresholds must be established for important plant-pathosystems. Plant pathogens in recycled irrigation water can be managed by a variety of treatment methods that can be arranged in four broad categories: cultural, physical, chemical, and biological. An integrated approach using one or more techniques from each category is likely to be the most effective strategy in combating plant pathogens in recycled irrigation water.

First report of Xanthomonas axonopodis pv. poinsettiicola, the bacterial leaf spot pathogen on Euphorbia pulcherrima in Austria

In September 2007 symptoms typical of bacterial leaf spot were observed on pot-grown Euphorbia pulcherrima in a commercial plant nursery in Carinthia, Austria. Leaf symptoms were dark to rust-brown spots with yellow haloes that sometimes coalesced to larger areas. Isolation of bacteria was performed on yeast agar (YPGA) and King's B Agar and colonies were more or less yellow and glossy. A strain of X. axonopodis pv. poinsettiicola (LMG849) from the Belgian Coordinates Collection of Microorganisms and a strain of X. campestris pv. vesicatoria (DSMZ 50861) from the German Collection of Microorganisms and Cell Cultures were used as controls. Identification was performed using two PCR assays, which combined allowed precise identification of the pathogen. Three pairs of oligonucleotide primers specific for different hrp gene regions of several pathovars from the X. campestris/axonopodis cluster were used for identification to species level (Leite et al., 1994). The 1075 bp amplicon described by Leite et al. (1994) was digested with HaeIII and Sau3AI, producing restriction patterns similar to those of X. campestris pv. vesicatoria and X. axonopodis pv. poinsettiicola. Additionally the PCR amplicons (1075 bp) of the isolated strain and the reference strain (LMG849) were sequenced. Phylogenetic sequence comparison grouped the sequence from the isolated strain with that from strain LMG849, lending further support to identification as X. axonopodis pv. poinsettiicola. A second PCR assay specific for X. campestris pv. vesicatoria designed to amplify the rhs family gene (Park et al., 2007) was negative. We therefore concluded that the bacteria isolated from diseased E. pulcherrima plants was X. axonopodis pv. poinsettiicola. Pathogenicity was confirmed by inoculating young E. pulcherrima plants with bacterial suspensions. After two weeks bacteria were re-isolated from newly emerged leaves. Isolates were identified as X. axonopodis pv. poinsettiicola using the molecular methods described above. Combining these two PCR assays, X. axonopodis pv. poinsettiicola isolates could be identified from leaves by amplification of DNA extracted from diseased material. This is the first report of X. axonopodis pv. poinsettiicola in Austria. An outbreak of this disease in nurseries would have a major economical impact, since E. pulcherrima is produced in yearly quantities of approximately 3·5 million units. The authors would like to thank Mr. Kelvin Hughes for his helpful comments on this manuscript.

First Report of Wisteria vein mosaic virus on Wisteria sinensis in New Zealand.

Wisteria vein mosaic virus (WVMV) is a member of the Potyvirus genus. The virus has been reported in Wisteria spp. in Australia, China, the United States, and a number of European countries (2). In 2006, several W. sinensis plants with mottling and mosaic symptoms were observed in a commercial plant nursery in Whenuapai, north of Auckland, New Zealand. These plants had been propagated from a nursery in the New Plymouth area of New Zealand. Sap from the symptomatic Wisteria plants was examined with an electron microscope and elongated and flexuous potyvirus-like particles approximately 750 nm long were observed. RNA was extracted from the symptomatic plants with a Qiagen RNeasy Plant Mini Kit (Doncaster, Australia). The RNA was initially tested using general potyvirus primers, PV1/SP6 (4) and U335 (3), with the cycling conditions of 94°C for 5 min followed by 40 cycles of 94°C for 45 s, 50°C for 45 s, 72°C for 90 s, and a final extension of 72°C for 7 min. The polymerase chain reaction (PCR) product (695 bp) was directly sequenced (GenBank Accession No. EU580146) and a BLAST search in GenBank showed 98% nucleotide identity with WVMV (GenBank Accession no. AF484549). The RNA was then tested using WVMV-specific primers, WVMVF1 and WVMVR1, and the published cycling conditions (2). PCR amplicons of 701 bp were obtained. PCR products were directly sequenced (GenBank Accession No. EU308592), and a BLAST search in GenBank showed 98% nucleotide identity with published sequences of WVMV (GenBank Accession Nos. AF484549 and AY656816). In addition, RNA was extracted from the original isolate of WVMV that was reported in the Netherlands (1; supplied by R. van der Vlugt, Plant Research International) and the RNA was amplified using the WVMV-specific primer pair. The sequence obtained from PCR amplicons of the type isolate (GenBank Accession No. EU308593) showed a 98% nucleotide identity with the New Zealand WVMV isolate and with published sequences of WVMV (as shown above). From the symptomatology, particle morphology, and nucleotide sequences, it is concluded that WVMV is present in New Zealand. The distribution of the virus in New Zealand is not known, but the affected plants at the New Plymouth nursery may have been imported into New Zealand as many as 30 years ago. Although WVMV infection can reduce the quality of commercial plants, the disease is not economically significant in New Zealand.

Garden plants get a head start on climate change

Conservation biologists are concerned that climate change will cause widespread extinctions because limited capacity for migration could compromise species' ability to adjust to geographic shifts in habitat condition. However, commercial plant nurseries may provide a head start for northward range shifts among some plant species. To investigate this possibility, we compared the natural ranges of 357 native European plant species with their commercial ranges, based on 246 plant nurseries throughout Europe. In 73% of native species, commercial northern range limits exceeded natural northern range limits, with a mean difference of ~ 1000 km. With migration rates of ~ 0.1–5 km per year required for geographic ranges to track climate change over the next century, we expect nurseries and gardens to provide a substantial head start on such migration for many native plants. While conservation biologists actively debate whether we should intentionally provide “assisted migration”, it is clear that we have already ...

First Report of Aulacaspis yasumatsui (Hemiptera: Diaspididae) in Africa (Ivory Coast), and Update on Distribution

Cycas species and their relatives have been a staple in the Florida landscapes for 50 years. In the last 25 to 30 years the popularity of these plants in the landscape has increased worldwide. In 1996, a devastating pest to cycads was intro duced into Florida, the cycad Aulacaspis scale (Aulacaspis yasumatsui Takagi). This insect has since plagued both homeowner and grower alike in Florida and has been a significant pest in many other areas of the world. The origin of the Cycad Aulacaspis scale (CAS) is from Southeast Asia where it was described in Thailand by Takagi (1977) from specimens col lected in Bangkok on Cycas sp. in 1972. It is cur rently considered established in the following Countries in Asia: in Hong-Kong, southern por tion of China (Howard & Wessling 1999), in Sin gapore in 2000 (Hodgson & Martin 2001), and also from Taiwan in 2000 (Shih 2003). Following its introduction in Florida in 1996 (Howard et al. 1999), A. yasumatsui spread in the Caribbean established in American Virgin Is lands, Cayman islands (Howard & Weissling 1999), Puerto Rico (Halbert 2000), Barbados 2003 (Ministry of Agriculture & Rural Development, Barbados website). In Oceania its presence is proven in Hawaii (Heu & Chun 2000) and CAS is regularly intercepted on cycads from Hawaii in California (G. Watson, personal communication). Although many of the southern states have inter cepted CAS on infested Cycas revoluta Thunb., it has only been verified as being established in the landscape in Louisiana (Pollet, Louisiana State University, personal communication) and Texas (samples verified by Hodges, FDACS-DPI, 2005). It is present in Micronesia on the island of Guam where it is causing major devastation to the natural forests (Moore et al. 2005) and it was intercepted in 2004, in New Zealand, on imported cycads of Costa-Rica. CAS was detected and all plants associated with it were destroyed (Paice et al. 2005) The authors emphasize that Aulacaspis yasumatsui is not established in NZ, on the other hand the origin of the cycads confirms the pres ence of CAS in Costa Rica. In Europe, CAS is regularly intercepted by many of the Plant Protection Services from vari ous European Countries. The first recorded inter ception dates to 1995 on cycads imported in the Netherlands and coming from Vietnam (Jansen, 1996). The Netherlands Plant Protection Service recorded CAS 5 times in 2004 and 4 times in 2005. The records are as follows: imported from Taiwan (lx), Vietnam (lx) and Costa Rica (2x) and the rest in greenhouses (5x). During the time period between 1995 and 2004 CAS was not detected (Jansen, personal communication). In France, it was intercepted several times in 2001 at the checkpoints of Marseille and in nurs ery gardens of the French Riviera, on imported cycads of Vietnam (Germain 2001a). The same year we identified CAS in the department of Ain, close to the Switzerland border, on a cycad coming from Germany (Germain 2001b). The species does not seem to have been established in France even though we found it on container and nursery grown cycads in Nice during Nov 2004. In the UK, CAS was detected at a commercial plant nursery in England on Cycads imported from Vietnam via the Netherlands on Apr 2006. This is the first in terception of this species in the UK. Action is be ing taken to eradicate the pest (C. Malumphy per sonal communication). In Italy this species has not been intercepted (G. Pellizzari, personal com munication). In the French department of the Antilles the Service de la Protection des V?g?taux of Martin ique indicated that armored scales near A. ya sumatsui were taken on cycads at Fort-de-France on Nov 3, 2005. Cycad Aulacaspis scale is re garded as established in Martinique. Its presence on imported cycads of Costa Rica in various coun tries makes it possible to affirm its spreading in Central America. In Jan 2006, A. yasumatsui Takagi (Hemip tera: Diaspididae) was identified in France from cut foliage of cycads imported from the Ivory Coast in Africa. This interception enables us to consider Cycad Aulacaspis Scale (CAS) as being present in the Ivory Coast, and would be consid ered as the first record of CAS in Africa. This

The removal of nutrients from plant nursery irrigation runoff in subsurface horizontal-flow wetlands

In New South Wales (NSW) Australia, the recent introduction of legislation to control runoff and charge for water used in agricultural production has encouraged commercial plant nurseries to collect and recycle their irrigation drainage. Runoff from a nursery typically contains around 6 mg/L TN (> 70% as NO3), 0.5 mg/L TP (> 50% as P04), and virtually no organic matter (BOD < 5 mg/L; DOC < 20 mg/L). As a result, algal blooms frequently occur in storage dams. This paper describes a study evaluating the effectiveness of subsurface flow wetlands in the removal of nutrients from nursery runoff on the sub-tropical northern coast of NSW, Australia. Four experimental subsurface flow wetlands (1 m x 4 m x 0.5 m water depth) were planted with Phragmites australis in April 1999. TN and TP load removals were > 84% and > 65% respectively at HRTs of between 5 and 2 days, with the majority of out-flowing TN and TP being organic in form. Internal generation of organic N and P resulted in persistent background levels of 0.45 mg/L TN and 0.15 mg/L TP in the reed bed effluent. TN, NH4 and TP removal was affected by HRT (P < 0.05). Greater than 90% load removal of NH4, NO2, NO3 and Ortho-P was achieved at all HRTs, with outlet concentrations generally < 0.01 mg/L for all. For TN, a strong relationship existed between removal rate (g/m2/day) and loading rate (r2 = 0.995), while a weaker relationship existed for TP (r2 = 0.47). It is estimated that a 1 ha nursery would require a reed bed area of 200 m2 for a 2 day HRT.

Quantification and Remediation of Pesticides in Runoff Water from Containerized Plant Production

AbstractDuring containerized plant production pesticides may move from application site in runoff water created by overhead irrigation systems. In this study, four pesticides, isoxaben {N‐[3‐(1‐ethyl‐1‐methylpropyl)‐5‐isoxazolyl]‐2,6‐dimethoxybenzamide}, trifluralin {(2,6‐dinitro‐N,N‐dipropyl‐4‐trifluoromethylaniline}, chlorpyrifos {O,O‐diethyl O‐3,5,6‐trichloro‐2‐pyridyl phosphorothioate) and thiophanate‐methyl {dimethyl 4,4−‐o‐phenylene bis(3‐thioallophanate), were applied at a commercial plant nursery. Overhead irrigation after application generated runoff water which was channeled into waterways of clay/gravel or hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy]. Isoxaben was detected in runoff water through 4 d after application (DAA). Other pesticides were detected primarily on the day of application (DOA). Thirteen percent of applied thiophanate‐methyl was recovered from the clay/gravel waterway and 11% from the grass waterway. Total amounts of isoxaben lost were 23% of total applied in both treatments. Less than 0.01% of applied chlorpyrifos and trifluralin were detected. Isoxaben amounts recovered from the grassed waterway on the DOA were 16% lower than from the clay/gravel treatment. Thiophanate‐methyl amounts were 18% lower from the grassed treatment on the DOA. The results suggest that vegetated waterways can reduce pesticide losses from application site in runoff water.