scholarly journals Response of Container-grown Nursery Plants to Chlorine Used to Disinfest Irrigation Water

HortScience ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 164-167 ◽  
Author(s):  
Diane Feliciano Cayanan ◽  
Mike Dixon ◽  
Youbin Zheng ◽  
Jennifer Llewellyn

The recycling of irrigation water may cause the dispersal of plant pathogens. Irrigation water disinfected with 2.4 mg·L−1 of free chlorine for 5 min was overhead-applied to 17 container-grown nursery plants for 11 weeks in a commercial nursery to evaluate the response of container-grown nursery plants to chlorine. No visual symptoms of injury or growth reduction were observed on the evergreen shrubs (Juniperus horizontalis, Thuja occidentalis, Buxus microphylla, Picea glauca, Rhododendron catawbiense, Taxus media, and Chamaecyparis pisifera), but there were visual injuries and/or growth reduction on some of the deciduous shrubs (Salix integra, Hydrangea paniculata, Prunus ×cistena, Weigela florida, Physocarpus opulifolius). Symptoms of anthracnose were reduced on Cornus alba plants treated with chlorinated water. The chlorine treatment did not affect leaf chlorophyll content. The chlorine treatment killed all fungi and oomycetes in the irrigation water (DNA multiscan). Although there were visible leaf injuries and growth reduction on some of the deciduous plants, chlorine injury did not render them unsalable. Results suggest that irrigation water treated with 2.4 mg·L−1 free chlorine for 5 min will effectively control the dispersal of common plant pathogens without reducing the market value of container-grown plants.

HortScience ◽  
2008 ◽  
Vol 43 (6) ◽  
pp. 1882-1887 ◽  
Author(s):  
Diane Feliciano Cayanan ◽  
Youbin Zheng ◽  
Ping Zhang ◽  
Tom Graham ◽  
Mike Dixon ◽  
...  

Phytotoxic responses of five container-grown nursery species (Spiraea japonica ‘Goldmound’, Hydrangea paniculata ‘Grandiflora’, Weigela florida ‘Alexandra’, Physocarpus opulifolius ‘Summer Wine’, and Salix integra ‘Hakura Nishiki’) to chlorinated irrigation water and critical free chlorine thresholds were evaluated. Plants were overhead-irrigated with water containing 0, 2.5, 5, 10, and 20 mg·L−1 of free chlorine for 6 weeks. The following measurements were used to assess the treatments: visual injury, growth, leaf chlorophyll content index, leaf chlorophyll fluorescence, leaf net CO2 exchange rate, and stomatal conductance. All species exhibited one or more signs of chlorine injury, including foliar necrotic mottling, foliar necrosis and chlorosis, decreased plant height, and increased premature abscission of foliage with species varying in sensitivity to free chlorine concentrations of irrigation water. The results indicated that the critical free chlorine threshold of S. japonica, H. paniculata, W. florida, and S. integra was 2.5 mg·L−1 and 5 mg·L−1 for P. opulifolius. Our results suggested that irrigation water containing free chlorine less than 2.5 mg·L−1 should not adversely affect the growth or appearance of ornamental woody shrubs.


HortScience ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 157-163 ◽  
Author(s):  
Diane Feliciano Cayanan ◽  
Ping Zhang ◽  
Weizhong Liu ◽  
Mike Dixon ◽  
Youbin Zheng

Recycled irrigation water is one of the major sources of inoculum and may spread plant pathogens throughout the nursery or greenhouse operation. Chlorination is the most economical method of disinfecting water and has been adopted by some North American commercial growers. However, chlorine has not been assessed as a disinfectant for the common plant pathogens Phytophthora infestans, Phytophthora cactorum, Pythium aphanidermatum, Fusarium oxysporum, and Rhizoctonia solani. These pathogens were exposed to five different initially free chlorine solution concentrations ranging from 0.3 to 14 mg·L−1 in combination with five contact times of 0.5, 1.5, 3, 6, and 10 min to determine the free chlorine threshold and critical contact time required to kill each pathogen. Results indicated that the free chlorine threshold and critical contact time for control of P. infestans, P. cactorum, P. aphanidermatum, F. oxysporum, and R. solani were 1, 0.3, 2, 14, and 12 mg·L−1 for 3, 6, 3, 6, and 10 min, respectively.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Serge Lévesque ◽  
Thomas Graham ◽  
Dorin Bejan ◽  
Jamie Lawson ◽  
Ping Zhang ◽  
...  

Abstract The capture and re-use of greenhouse fertigation water is an efficient use of fertilizer and limited water resources, although the practice is not without risk. Plant pathogens and chemical contaminants can build up over successive capture and re-use cycles; if not properly managed they can lead to reduced productivity or crop loss. There are numerous established and emerging water treatment technologies available to treat fertigation water. Electrochemical processes are emerging as effective means for controlling pathogens via in situ regenerative hypochlorination; a process that is demonstrated here to achieve pathogen control in fertigation solutions without leading to the accumulation of potentially phytotoxic free chlorine residuals associated with other chlorination processes. An electrochemical flow cell (EFC) outfitted with ruthenium dioxide (RuO2) dimensionally stable anodes (DSA) was characterized and evaluated for free chlorine production and Rhizoctonia solani inactivation in both irrigation and fertigation solutions. Pathogen inactivation was achieved at low current densities and short residence or cell contact times. Effluent free chlorine concentrations were significantly lower than commonly reported phytotoxic threshold values (approximately 2.5 mg/L) when fertilizer (containing ammonium) was present in the test solution; an effect attributable to reactions associated with breakpoint chlorination, including chloramine formation, as well as the presence of other oxidizable compounds in the fertilizer. Chloride concentrations were stable under the test conditions suggesting that the EFC was operating as a regenerative in situ electrochemical hypochlorination system. No significant changes to macronutrient concentrations were found following passage through the EFC.


Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 459 ◽  
Author(s):  
Adas Marčiulynas ◽  
Diana Marčiulynienė ◽  
Jūratė Lynikienė ◽  
Artūras Gedminas ◽  
Miglė Vaičiukynė ◽  
...  

The aim of the present study was to assess fungal and oomycete communities in the irrigation water of forest nurseries, focusing on plant pathogens in the hope of getting a better understanding of potential pathogenic microorganisms and spreading routes in forest nurseries. The study sites were at Anykščiai, Dubrava, Kretinga and Trakai state forest nurseries in Lithuania. For the collection of microbial samples, at each nursery five 100-L water samples were collected from the irrigation ponds and filtered. Following DNA isolation from the irrigation water filtrate samples, these were individually amplified using ITS rDNA as a marker and subjected to PacBio high-throughput sequencing. Clustering in the SCATA pipeline and the taxonomic classification of 24,006 high-quality reads showed the presence of 1286 non-singleton taxa. Among those, 895 were representing fungi and oomycetes. The detected fungi were 57.3% Ascomycota, 38.1% Basidiomycota, 3.1% Chytridiomycota, 0.8% Mucoromycota and 0.7% Oomycota. The most common fungi were Malassezia restricta E. Guého, J. Guillot & Midgley (20.1% of all high-quality fungal sequences), Pezizella discreta (P. Karst.) Dennis (10.8%) and Epicoccum nigrum Link (4.9%). The most common oomycetes were Phytopythium cf. citrinum (B. Paul) Abad, de Cock, Bala, Robideau, Lodhi & Lévesque (0.4%), Phytophthora gallica T. Jung & J. Nechwatal (0.05%) and Peronospora sp. 4248_322 (0.05%). The results demonstrated that the irrigation water used by forest nurseries was inhabited by a species-rich but largely site-specific communities of fungi. Plant pathogens were relatively rare, but, under suitable conditions, these can develop rapidly, spread efficiently through the irrigation system and be a threat to the production of high-quality tree seedlings.


Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2558 ◽  
Author(s):  
Andrew Ristvey ◽  
Bruk Belayneh ◽  
John Lea-Cox

Water security in ornamental plant production systems is vital for maintaining profitability. Expensive, complicated, or potentially dangerous treatment systems, together with skilled labor, is often necessary to ensure water quality and plant health. Two contrasting commercial ornamental crop production systems in a mesic region are compared, providing insight into the various strategies employed using irrigation-water containment and treatment systems. The first is a greenhouse/outdoor container operation which grows annual ornamental plants throughout the year using irrigation booms, drip emitters, and/or ebb and flow systems depending on the crop, container size, and/or stage of growth. The operation contains and recycles 50–75% of applied water through a system of underground cisterns, using a recycling reservoir and a newly constructed 0.25 ha slow-sand filtration (SSF) unit. Groundwater provides additional water when needed. Water quantity is not a problem in this operation, but disease and water quality issues, including agrochemicals, are of potential concern. The second is a perennial-plant nursery which propagates cuttings and produces field-grown trees and containerized plants. It has a series of containment/recycling reservoirs that capture rainwater and irrigation return water, together with wells of limited output. Water quantity is a more important issue for this nursery, but poor water quality has had some negative economic effects. Irrigation return water is filtered and sanitized with chlorine gas before being applied to plants via overhead and micro-irrigation systems. The agrochemical paclobutrazol was monitored for one year in the first operation and plant pathogens were qualified and quantified over two seasons for both production systems. The two operations employ very different water treatment systems based on their access to water, growing methods, land topography, and capital investment. Each operation has experienced different water quantity and quality vulnerabilities, and has addressed these threats using a variety of technologies and management techniques to reduce their impacts.


2019 ◽  
Vol 3 (1) ◽  
pp. 31-45 ◽  
Author(s):  
Neelam R. Redekar ◽  
Joyce L. Eberhart ◽  
Jennifer L. Parke

Recycling of irrigation water increases disease risks due to spread of waterborne oomycete plant pathogens such as Phytophthora, Pythium, and Phytopythium. A comprehensive metabarcoding study was conducted to determine spatial and temporal dynamics of oomycete communities present in irrigation water collected from a creek (main water source), a pond, retention reservoirs, a chlorinated water reservoir, and runoff channels within a commercial container nursery in Oregon over the course of 1 year. Two methods, filtration and leaf baiting, were compared for the detection of oomycete communities. Oomycete communities in recycled irrigation water were less diverse but highly enriched with biologically active plant pathogens as compared with the creek water. The filtration method captured a larger portion of oomycete diversity, while leaf baiting was more selective for plant-associated oomycete species of Phytophthora and a few Pythium and Phytopythium species. Seasonality strongly influenced oomycete diversity in irrigation water and detection with leaf baiting. Phytophthora was the major colonizer of leaf baits in winter, while all three genera were equally abundant on leaf baits in summer. The metabarcoding approach was highly effective in studying oomycete ecology, however, it failed to distinguish some closely related species. We developed a custom oomycete internal transcribed spacer (ITS)1 reference database containing shorter sequences flanked by ITS6 and ITS7 primers used in metabarcoding and used it to assemble a list of indistinguishable species complexes and clusters to improve identification. The predominant bait-colonizing species detected in recycled irrigation water were the Phytophthora citricola-complex, Phytophthora syringae, Phytophthora parsiana-cluster, Phytophthora chlamydospora, Phytophthora gonapodyides, Phytophthora irrigata, Phytophthora taxon Oaksoil-cluster, Phytophthora citrophthora-cluster, Phytophthora megasperma-cluster, Pythium chondricola-complex, Pythium dissotocum-cluster, and Phytopythium litorale.


2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
Sarah M. Higbie ◽  
Fei Wang ◽  
J. McD. Stewart ◽  
Tracy M. Sterling ◽  
William C. Lindemann ◽  
...  

In the southwestern and western Cotton Belt of the U.S. soil salinity can reduce cotton productivity and quality. This study was conducted to determine the physiological responses of six genotypes including five Upland cotton (Gossypium hirsutumL.) cultivars and one Pima cotton line (G. barbadenseL.) to NaCl under greenhouse conditions. Seeds were germinated and grown for 14 days prior to salt treatment (daily 100 ml of 200 mM NaCl) for 21 days. Compared with the control (daily 100 ml tap water), the NaCl treatment significantly reduced plant height, leaf area, fresh weight, and dry weight. The NaCl stress also significantly increased leaf chlorophyll content, but did not affect leaf fluorescence. Of the six genotypes, Pima 57-4 and SG 747 had the most growth reduction, and were most sensitive to NaCl; DP 33B, JinR 422 and Acala Phy 72 had the least growth reduction and were most NaCl tolerant. Although all the six genotypes under the salt treatment had significantly higher Na and Cl accumulation in leaves, SG 747 and Pima 57-4 accumulated more Na and Cl than DP 33B. Increases in leaf N, Zn, and Mn concentrations were also observed in the NaCl-treated plants. While leaf P, Ca, and S concentrations remained unchanged overall in the genotypes tested, leaf K, Mg, Fe, and Cu concentrations significantly decreased during salt stress. Reduction in plant height is a simple, easy, sensitive, non-destructive measurement to evaluate salt tolerance in cotton.


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