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Croatia: Aquaponics session at Aquaculture Europe 2017

Dubrovnik Hydroponics

Plant Pathogens and Control Strategies in Aquaponics

Dubrovnik Hydroponics

Aquaponics Food Production Systems pp Cite as. Among the diversity of plant diseases occurring in aquaponics, soil-borne pathogens, such as Fusarium spp. Phytophthora spp. In coupled aquaponics, curative methods are still limited because of the possible toxicity of pesticides and chemical agents for fish and beneficial bacteria e. Furthermore, the development of biocontrol agents for aquaponic use is still at its beginning. Consequently, ways to control the initial infection and the progression of a disease are mainly based on preventive actions and water physical treatments. However, suppressive action suppression could happen in aquaponic environment considering recent papers and the suppressive activity already highlighted in hydroponics. In addition, aquaponic water contains organic matter that could promote establishment and growth of heterotrophic bacteria in the system or even improve plant growth and viability directly. With regards to organic hydroponics i. In the future, research on the disease suppressive ability of the aquaponic biotope must be increased, as well as isolation, characterisation and formulation of microbial plant pathogen antagonists. Finally, a good knowledge in the rapid identification of pathogens, combined with control methods and diseases monitoring, as recommended in integrated plant pest management, is the key to an efficient control of plant diseases in aquaponics. Nowadays, aquaponic systems are the core of numerous research efforts which aim at better understanding these systems and at responding to new challenges of food production sustainability Goddek et al. In spite of this increasing number of papers and the large area of study topics they are covering, one critical point is still missing, namely plant pest management Stouvenakers et al. In aquaponics, the diseases might be similar to those found in hydroponic systems under greenhouse structures. Among the most problematic pathogens, in term of spread, are hydrophilic fungi or fungus-like protists which are responsible for root or collar diseases. To consider plant pathogen control in aquaponics, firstly, it is important to differentiate between coupled and decoupled systems. Decoupled systems allow disconnection between water from the fish and crop compartment see Chap. This separation allows the optimisation and a better control of different parameters e. Furthermore, if the water from the crop unit does not come back to the fish part, the application of phytosanitary treatments e. Coupled systems are built in one loop where water recirculates in all parts of the system see Chaps. However, in coupled systems, plant pest control is more difficult due to the both presence of fish and beneficial microorganisms which transform fish sludge into plant nutrients. Their existence limits or excludes the application of already available disinfecting agents and chemical treatments. Furthermore no pesticides or biopesticides have been specifically developed for aquaponics Rakocy et al. Control measures are consequently mainly based on non-curative physical practices see Sect. On the other hand, recent studies highlight that aquaponic plant production offers similar yields when compared to hydroponics although concentrations of mineral plant nutrients are lower in aquaponic water. Furthermore, when aquaponic water is complemented with some minerals to reach hydroponic concentrations of mineral nutritive elements, even better yields can be observed Pantanella et al. Moreover, some informal observations from practitioners in aquaponics and two recent scientific studies Gravel et al. Biostimulation is defined as the enhancement of plant quality traits and plant tolerance against abiotic stress using any microorganism or substance. With regard to these aspects, this chapter has two main objectives. The first is to give a review of microorganisms involved in aquaponic systems with a special focus on plant pathogenic and plant beneficial microorganisms. Factors influencing these microorganisms will be also considered e. The second is to review available methods and future possibilities in plant diseases control. Microorganisms are present in the entire aquaponics system and play a key role in the system. They are consequently found in the fish, the filtration mechanical and biological and the crop parts. Commonly, the characterisation of microbiota i. Up until now, in aquaponics, most of microbial research has focused on nitrifying bacteria Schmautz et al. Thus, the trend at present is to characterise microorganisms in all compartments of the system using modern sequencing technologies. Schmautz et al. In the following sub-sections, focus will be only brought on microorganisms interacting with plants in aquaponic systems organised into plant beneficial and plant pathogenic microorganisms. Plant pathogens occurring in aquaponic systems are theoretically those commonly found in soilless systems. A specificity of aquaponic and hydroponic plant culture is the continuous presence of water in the system. For root pathogens some are particularly well adapted to these conditions like pseudo-fungi belonging to the taxa of Oomycetes e. These zoospores are able to move actively in liquid water and thus are able to spread over the entire system extremely quickly. Though Oomycetes are among the most prevalent pathogens detected during root diseases, they often form a complex with other pathogens. Other fungal genera like Verticillium and Didymella , but also bacteria, such as Ralstonia , Xanthomonas , Clavibacter , Erwinia and Pseudomonas , as well as viruses e. However note that not all microorganisms detected are damaging or lead to symptoms in the crop. Even species of the same genus can be either harmful or beneficial e. Fusarium , Phoma , Pseudomonas. Disease agents discussed above are mainly pathogens linked to water recirculation but can be identified in greenhouses also. Section In hydroponics or in aquaponic systems, plants generally grow under greenhouse conditions optimized for plant production, especially for large-scale production where all the environmental parameters are computer managed Albajes et al. However, optimal conditions for plant production can also be exploited by plant pathogens. In fact, these structures generate warm, humid, windless and rain-free conditions that can encourage plant diseases if they are not correctly managed ibid. To counteract this, compromises must be made between optimal plant conditions and disease prevention ibid. In the microclimate of the greenhouse, an inappropriate management of the vapour-pressure deficit can lead to the formation of a film or a drop of water on the plants surface. This often promotes plant pathogen development. Moreover, to maximise the yield in commercial hydroponics, some other parameters e. Basic steps 1 to 6 in plant disease epidemiological cycle EpC according to Lepoivre The pathogen-plant relationship is incompatible non-host relation and disease does not develop. There is a host relation but the plant does not show symptoms the plant is tolerant. The pathogen and the plant are compatible but defence response is strong enough to inhibit the progression of the disease the plant is resistant: interaction between host resistance gene and pathogen avirulence gene. The plant is sensitive host relation without gene for gene recognition , and the pathogen infects the plant, but symptoms are not highly severe step 4 in the EpC. And lastly, the plant is sensitive and disease symptoms are visible and severe step 4 in the EpC. Adding factors encouraging plant pathogen development under aquaponic greenhouse structure compared to classical greenhouse culture. Pythium spp. Easy spread by water recirculation; possibility of post contamination after a disinfection step; poor content in oxygen in the nutrient solution. Koohakan et al. Higher content in bacteria no information about their possible pathogenicity. Khalil and Alsanius , Koohakan et al. Higher content in fungi; higher content in Fusarium spp. Van Der Gaag and Wever , Vallance et al. Better condition for zoospores dispersal and chemotaxis movement; no loss of zoospore flagella. Plant stressed and optimal condition for Pythium growth. Cherif et al. Albajes et al. Plant physiological modifications e. Colhoun , Snoeijers and Alejandro , Mitchell et al. In the epidemiological cycle, once the infective stage is reached step 5 in the EpC , the pathogens can spread in several ways Fig. As explained before, root pathogens belonging to Oomycetes taxa can actively spread in the recirculating water by zoospores release Alhussaen ; Sutton et al. For other fungi, bacteria and viruses responsible for root or aerial diseases, the dispersion of the causal agent can occur by propagation of infected material, mechanical wounds, infected tools, vectors e. Twenty-eight answers were received describing 32 aquaponic systems from around the world EU, 21; North America, 5; South America, 1; Africa, 4; Asia, 1. The first finding was the small response rate. Among the possible explanations for the reluctance to reply to the questionnaire was that practitioners did not feel able to communicate about plant pathogens because of a lack of knowledge on this topic. This had already been observed in the surveys of Love et al. These results support the previous arguments saying that aquaponic plants do get diseases. Yet, practitioners suffer from a lack of knowledge about plant pathogens and disease control measures actually used are essentially based on non-curative actions Results of the first identifications of plant pathogens in aquaponics from the international survey analysis and from existing literature. Plant pathogens identified by symptoms in the aerial plant part are annotated by a and in root part by b in exponent. Review of occurring symptoms in aquaponics from the international survey analysis. Allium schoenoprasum 1 , Amaranthus viridis 1 , Coriandrum sativum 1 , Cucumis sativus 1 , Ocimum basilicum 6 , Lactuca sativa 4 , Mentha spp. Mentha spp. Cucumis sativus 1 , Mentha spp. Brassica oleracea Acephala group 1 , Lactuca sativa 1 , Mentha spp. Allium schoenoprasum 1 , Capsicum annuum 1 , Cucumis sativus 1 , Lactuca sativa 2 , Mentha spp. Capsicum annuum 1 , Cucumis sativus 1 , Lactuca sativa 2 , Mentha spp. Spinacia oleracea 1 , Ocimum basilicum 1 , Solanum lycopersicum 1 , seedlings in general 5. Beta vulgaris swiss chard 1 , Capsicum annuum 1 , Lactuca sativa 1 , Ocimum basilicum 1. Allium schoenoprasum 1 , Amaranthus viridis 1 , Beta vulgaris swiss chard 1 , Coriandrum sativum 1 , Lactuca sativa 1 , Mentha spp. Numbers in exponent represent the occurrence of the symptom for a specific plant on a total of 32 aquaponic systems reviewed. This section reviews the potential of plant beneficial microorganisms involved in aquaponics and their modes of action. Sirakov et al. Among the tested isolates, 86 showed a strong inhibitory effect on Pythium ultimum in vitro. Further research must be achieved to taxonomically identify these bacteria and evaluate their potential in in vivo conditions. The authors assume that many of these isolates belong to the genus Pseudomonas. Antagonistic species of the genus Pseudomonas were able to control plant pathogens in natural environments e. They can protect plants against pathogens either in an active or a passive way by eliciting a plant defence response, playing a role in plant growth promotion, compete with pathogens for space and nutrients e. Although no identification of microorganisms was done by Gravel et al. Information about the possible natural plant protection capacity of aquaponic microbiota is scarce, but the potential of this protective action can be envisaged with regard to different elements already known in hydroponics or in recirculated aquaculture. A first study was conducted in on suppressive action or suppressiveness promoted by microorganisms in soilless culture McPherson et al. Suppressiveness in hydroponics, here defined by Postma et al. The suppressive action of a milieu can be related to the abiotic environment e. In soilless culture, the suppressive capacity shown by water solution or the soilless media is reviewed by Postma et al. In these reviews, microorganisms responsible for this suppressive action are not clearly identified. In contrast, plant pathogens like Phytophthora cryptogea , Pythium spp. In the various articles reviewed by Postma et al. When compared with an open system without recirculation, suppressive activity in soilless systems could be explained by the water recirculation McPherson et al. Review of plant pathogens effectively removed by slow filtration in hydroponics. Xanthomonas campestris pv. Wohanka , Ehret et al. Ehret et al. Van Os et al. Good agricultural practices GAP for plant pathogens control are the various actions aiming to limit crop diseases for both yield and quality of produce FAO GAP transposable to aquaponics are essentially non-curative physical or cultivation practices that can be divided in preventive measures and water treatment. Preventive measures have two distinct purposes. The first is to avoid the entry of the pathogen inoculum into the system and the second is to limit i plant infection, ii development and iii spread of the pathogen during the growing period. Preventive measures aiming to avoid the entry of the initial inoculum in the greenhouse are, for example, a fallow period, a specific room for sanitation, room sanitation e. Among the most important practices used for the second type of preventive measures are, the use of resistant plant varieties, tools disinfection, avoidance of plant abiotic stresses, good plant spacing, avoidance of algae development and environmental conditions management. The last measure, i. Generally, in large-scale greenhouse structures, computer software and algorithms are used to calculate the optimal parameters allowing both plant production and disease control. The parameters measured, among others, are temperature of the air and the nutrient solution , humidity, vapour pressure deficit, wind speed, dew probability, leaf wetness and ventilation ibid. The practitioner acts on these parameters by manipulating the heating, the ventilation, the shading, the supplement of lights, the cooling and the fogging ibid. Physical water treatments can be employed to control potential water pathogens. These techniques allow the control of disease outbreaks by decreasing the inoculum, the quantity of pathogens and their proliferation stages in the irrigation system ibid. Physical disinfection decreases water pathogens to a certain level depending on the aggressiveness of the treatment. Generally, the target of heat and UV disinfection is the reduction of the initial microorganisms population by 90— The filtration technique most used is slow filtration because of its reliability and its low cost. The substrates of filtration generally used are sand, rockwool or pozzolana ibid. Filtration efficiency is essentially dependent on pore size and flow. Nevertheless, it allows a suppression of plant debris, algae, small particles and some soil-borne diseases such as Pythium and Phytophthora the efficiency is genus dependent. Slow filters do not act only by physical action but also show a microbial suppressive activity, thanks to antagonistic microorganisms, as discussed in Sect. Heat treatment is very effective against plant pathogens. This practice consumes a lot of energy and imposes water cooling heat exchanger and transitional tank before reinjection of the treated water back into the irrigation loop. In addition, it has the disadvantage of killing all microorganisms including the beneficial ones Hong and Moorman ; Postma et al. The last technique and probably the most applied is UV disinfection. UV radiation has a wavelength of to nm. It has a detrimental effect on microorganisms by direct damage of the DNA. Physical water treatments eliminate the most of the pathogens from the incoming water but they cannot eradicate the disease when it is already present in the system. Physical water treatment does not cover all the water especially the standing water zone near the roots , nor the infected plant tissue. For example, UV treatments often fail to suppress Pythium root rot Sutton et al. However, if physical water treatment allows a reduction of plant pathogens, theoretically, they also have an effect on nonpathogenic microorganisms potentially acting on disease suppression. In reality, heat and UV treatments create a microbiological vacuum, whereas slow filtration produces a shift in effluent microbiota composition resulting in a higher disease suppression capacity Postma et al. This was probably due to a too low quantity of water treated and a re-contamination of the water after contact with the irrigation system, roots and plant media ibid. Aquaponic water treatment by means of chemicals is limited in continuous application. Ozonation is a technique used in recirculated aquaculture and in hydroponics. However it has several disadvantages. Introducing ozone in raw water can produce by-products oxidants and significant amount of residual oxidants e. Furthermore, ozone treatment is expensive, is irritant for mucous membranes in case of human exposure, needs contact periods of 1 to 30 minutes at a concentration range of 0. The experiments introducing microorganisms in aquaponic systems have been focused on the increase of nitrification by addition of nitrifying bacteria Zou et al. There is now an urgent need to work on biocontrol agents BCA against plant pathogens in aquaponics with regard to the restricted use of synthetic curative treatments, the high value of the culture and the increase of aquaponic systems in the world. BCA are defined, in this context, as viruses, bacteria and fungi exerting antagonistic effects on plant pathogens Campbell ; Narayanasamy Generally, the introduction of a BCA is considered to be easier in soilless systems. In fact, the hydroponic root environment is more accessible than in soil and the microbiota of the substrate is also unbalanced due to a biological vacuum. Furthermore, environmental conditions of the greenhouse can be manipulated to achieve BCA growth needs. However, in practice, the effectiveness of BCA inoculation to control root pathogens can be highly variable in soilless systems Postma et al. One explanation for this is that BCA selection is based on in vitro tests which are not representing real conditions and subsequently a weak adaptation of these microorganisms to the aquatic environment used in hydroponics or aquaponics Postma et al. To control plant pathogens and more especially those responsible for root rots, a selection and identification of microorganisms involved in aquatic systems which show suppressive activity against plant pathogens is needed. In soilless culture, several antagonistic microorganisms can be picked due to their biological cycle being similar to root pathogens or their ability to grow in aqueous conditions. The direct addition of some microbial metabolites such as biosurfactants has also been studied Stanghellini and Miller ; Nielsen et al. Although some microorganisms are efficient at controlling root pathogens, there are other problems that need to be overcome in order to produce a biopesticide. The main challenges are to determine the means of inoculation, the inoculum density, the product formulation Montagne et al. Ecotoxicological studies on fish and living beneficial microorganisms in the system are also an important point. Another possibility that could be exploited is the use of a complex of antagonistic agents, as observed in suppressive soil techniques Spadaro and Gullino ; Vallance et al. In fact, microorganisms can work in synergy or with complementary modes of action ibid. The addition of amendments could also enhance the BCA potential by acting as prebiotics see Sect. In Sect. As stated before, the main hypothesis is related to the water recirculation as it is for hydroponic systems. However, a second hypothesis exists and this is linked to the presence of organic matter in the system. Organic matter that could drive a more balanced microbial ecosystem including antagonistic agents which is less suitable for plant pathogens Rakocy In aquaponics, organic matter comes from water supply, uneaten feeds, fish faeces, organic plant substrate, microbial activity, root exudates and plant residues Waechter-Kristensen et al. In such a system, heterotrophic bacteria are organisms able to use organic matter as a carbon and energy source, generally in the form of carbohydrates, amino acids, peptides or lipids Sharrer et al. In recirculated aquaculture RAS , they are mainly localised in the biofilter and consume organic particles trapped in it Leonard et al. However, another source of organic carbon for heterotrophic bacteria is humic substances present as dissolved organic matter and responsible for the yellow-brownish coloration of the water Takeda and Kiyono cited by Leonard et al. In the soil as well as in hydroponics, humic acids are known to stimulate plant growth and sustain the plant under abiotic stress conditions Bohme ; du Jardin Proteins in the water can be used by plants as an alternative nitrogen source thus enhancing their growth and pathogen resistance Adamczyk et al. As implied, heterotrophic microorganisms can have a negative impact on the system because they compete with autotrophic bacteria e. Some of them are plant or fish pathogens, or responsible for off-flavour in fish Chang-Ho ; Funck-Jensen and Hockenhull ; Jones et al. However, heterotrophic microorganisms involved in the system can also be positive Whipps ; Mukerji Several studies using organic fertilizers or organic soilless media, in hydroponics, have shown interesting effects where the resident microbiota were able to control plant diseases Montagne et al. All organic substrates have their own physico-chemical properties. Consequently, the characteristics of the media will influence microbial richness and functions. The choice of a specific plant media could therefore influence the microbial development so as to have a suppressive effect on pathogens Montagne et al. Another possibility of pathogen suppression related to organic carbon is the use of organic amendments in hydroponics Maher et al. By adding composts in soilless media like it is common use in soil, suppressive effects are expected Maher et al. Enhancing or maintaining a specific microorganism such as Pseudomonas population by adding some formulated carbon sources e. The emergence of organic soilless culture also highlights the involvement of beneficial microorganisms against plant pathogens supported by the use of organic fertilizers. Fujiwara et al. Finally, though information about the impact of organic matter on plant protection in aquaponics is scarce, the various elements mentioned above show their potential capacity to promote a system-specific and plant pathogen-suppressive microbiota. This chapter aimed to give a first report of plant pathogens occurring in aquaponics, reviewing actual methods and future possibilities to control them. Each strategy has advantages and disadvantages and must be thoroughly designed to fit each case. However, at this time, curative methods in coupled aquaponic systems are still limited and new perspectives of control must be found. Fortunately, suppressiveness in terms of aquaponic systems could be considered, as already observed in hydroponics e. In addition, the presence of organic matter in the system is an encouraging factor when compared to soilless culture systems making use of organic fertilisers, organic plant media or organic amendments. For the future, it seems important to investigate this suppressive action followed by identification and characterization of the responsible microbes or microbe consortia. Based on the results, several strategies could be envisaged to enhance the capacity of plants to resist pathogens. The first is biological control by conservation, which means favouring beneficial microorganisms by manipulating and managing water composition e. But identification of these influencing factors needs to be realized first. This management of autotrophic and heterotrophic bacteria is also of key importance to sustain good nitrification and keep healthy fish. The second strategy is augmentative biological control by additional release of beneficial microorganisms already present in the system in large numbers inundative method or in small numbers but repeated in time inoculation method. But prior identification and multiplication of an aquaponic BCA should be achieved. The third strategy is importation, i. In this case, selection of a microorganism adapted and safe for aquaponic environment is needed. For the two last strategies, the site of inoculation in the system must be considered depending on the aim desired. Sites where microbial activity could be enhanced are the recirculated water, the rhizosphere plant media included , the biofilter such as in slow sand filters where BCA addition is already tested and the phyllosphere i. Whatever the strategy, the ultimate goal should be to lead the microbial communities to provide a stable, ecologically balanced microbial environment allowing good production of both plant and fish. To conclude, following the requirements of integrated plant pest management IPM is a necessity to correctly manage the system and avoid development and spread of plant diseases Bittsanszky et al. The principle of IPM is to apply chemical pesticides or other agents as a last resort when economic injury level is reached. Consequently, control of pathogens will need to be firstly based on physical and biological methods described above , their combination and an efficient detection and monitoring of the disease European Parliament The images or other third party material in this chapter are included in the chapter's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the chapter's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. Skip to main content Skip to sections. This service is more advanced with JavaScript available. Advertisement Hide. Plant Pathogens and Control Strategies in Aquaponics. Open Access. First Online: 22 June Download chapter PDF. The question now is to know by which route the initial inoculum i. The different steps in plant disease epidemiological cycle EpC are represented in Fig. In aquaponics, as in greenhouse hydroponic culture, it can be considered that entry of pathogens could be linked to water supply, introduction of infected plants or seeds, the growth material e. Open image in new window. Once the inoculum is in contact with the plant step 2 in the EpC , several cases of infection step 3 in the EpC are possible Lepoivre : The pathogen-plant relationship is incompatible non-host relation and disease does not develop. Regardless of the degree of resistance, some environmental conditions or factors can influence the susceptibility of a plant to be infected, either by a weakening of the plant or by promoting the growth of the plant pathogen Colhoun ; Jarvis ; Cherif et al. The main environmental factors influencing plant pathogens and disease development are temperature, relative humidity RH and light ibid. In hydroponics, temperature and oxygen concentrations within the nutrient solution can constitute additional factors Cherif et al. Each pathogen has its own preference of environmental conditions which can vary during its epidemiologic cycle. Colhoun sums up the effects of the various factors promoting plant diseases in soil, whereas Table Table Easy spread by water recirculation; possibility of post contamination after a disinfection step; poor content in oxygen in the nutrient solution Koohakan et al. Better condition for zoospores dispersal and chemotaxis movement; no loss of zoospore flagella Sutton et al. Plant stressed and optimal condition for Pythium growth Cherif et al. Key information obtained from the survey are: In the survey, a listing of plant pathogens occurring in their aquaponic system was provided. The presence of 3 plant pathologists in the survey respondents expands the list, with the identification of some root pathogens e. General symptoms that are not specific enough to be directly related to a pathogen without further verification see diagnosis in Sect. But it is important to highlight that most of the symptoms observed in this table could also be the consequence of abiotic stresses. Foliar chlorosis is one of the most explicit examples because it can be related to a large number of pathogens e. Plant host Plant pathogen References or survey results Allium schoenoprasu Pythium sp. Pythium sp. Symptoms Plants species Foliar chlorosis Allium schoenoprasum 1 , Amaranthus viridis 1 , Coriandrum sativum 1 , Cucumis sativus 1 , Ocimum basilicum 6 , Lactuca sativa 4 , Mentha spp. Since , suppressiveness of hydroponic systems has been generally accepted and research topics have been more driven on isolation and characterization of antagonistic strains in soilless culture with Pseudomonas species as main organisms studied. If it was demonstrated that soilless culture systems can offer suppressive capacity, there is no similar demonstration of such activity in aquaponics systems. However, there is no empiric indication that it should not be the case. This optimism arises from the discoveries of Gravel et al. Moreover, it has been shown in hydroponics Haarhoff and Cleasby cited by Calvo-bado et al. In hydroponics, slow filtration has been demonstrated to be effective against the plant pathogens reviewed in Table However, additional modes of action could be present for these two genera as already explained for Pseudomonas spp. Cell wall-degrading enzymes, bacteriocins, and antibiotics, lipopeptides i. All things considered, the functioning of a slow filter is not so different from the functioning of some biofilters used in aquaponics. Furthermore, some heterotrophic bacteria like Pseudomonas spp. Nevertheless, up until now, no study about the possible suppressiveness in aquaponic biofilters has been carried out. Plant pathogens References Xanthomonas campestris pv. Pelargonii Brand Fusarium oxysporum Wohanka , Ehret et al. At the moment aquaponic practitioners operating a coupled system are relatively helpless against plant diseases when they occur, especially in the case of root pathogens. No pesticide nor biopesticide is specifically developed for aquaponic use Rakocy ; Rakocy ; Somerville et al. In brief, curative methods are still lacking. Only Somerville et al. In any case, an appropriate diagnostic of the pathogen s causing the disease is mandatory in order to identify the target s for curative measures. This diagnosis requires good expertise in terms of observation capacity, plant pathogen cycle understanding and analysis of the situation. However, in case of generalist not specific symptoms and depending on the degree of accuracy needed, it is often necessary to use laboratory techniques to validate the hypothesis with respect to the causal agent Lepoivre Postma et al. Direct macroscopic and microscopic observation of the pathogen. Preventive Measures Preventive measures have two distinct purposes. Water Treatment Physical water treatments can be employed to control potential water pathogens. In hydroponics, numerous scientific papers review the use of antagonistic microorganisms i. The mode of action of these antagonistic microorganisms is according to Campbell , Whipps and Narayanasamy grouped in: 1. Competition for nutrients and niches. Adamczyk B, Smolander A, Kitunen V, Godlewski M Proteins as nitrogen source for plants: a short story about exudation of proteases by plant roots. Plant Signal Behav — Kluwer Academic Publishers. Alhussaen K Pythium and phytophthora associated with root disease of hydroponic lettuce. University of Technologie Sydney Faculty of Science. Horticulturae Arras G, Arru S Mechanism of action of some microbial antagonists against fungal pathogens. Ann Microbiol Enzimol — Google Scholar. Aquac Eng — Front Microbiol Genet Mol Biol 35 4 — Google Scholar. Bohme M Effects of Lactate, Humate and Bacillus subtilis on the growth of tomato plants in hydroponic systems. In: International symposium on growing media and hydroponics. Acta Horticulturae, pp — Google Scholar. Brand T Importance and characterization of the biological component in slow filters. Acta Hortic — Google Scholar. Appl Enviromental Microbiol — Campbell R Biological control of microbial plant pathogens. Chang-Ho Y The effect of pea root exudate on the germination of Pythium aphanidermatum zoospore cysts. Can J Bot — Google Scholar. Biol Control — Cherif M, Tirilly Y, Belanger RR Effect of oxygen concentration on plant growth, lipid peroxidation, and receptivity of tomato roots to Pythium under hydroponic conditions. J Sci Food Agric — J Plant Interact — Colhoun J Effects of environmental factors on plant disease. Annu Rev Phytopathol — Google Scholar. Sci Hortic Amsterdam — Sucrine growth performance in complemented aquaponic solution outperforms hydroponics. Water — Can J Microbiol — Dordas C Role of nutrients in controlling plant diseases in sustainable agriculture: a review. Agron Sustain Dev — Agronomie — October , pp 71— Accessed 27 Feb Control — J Gen Plant Pathol. Microbiologyopen — Funck-Jensen D, Hockenhull J Is damping-off, caused by Pythium, less of a problem in hydroponics than in traditional growing systems? Furtner B, Bergstrand K, Brand T Abiotic and biotic factors in slow filters integrated to closed hydroponic systems. Ganeshan G, Kumar AM Pseudomonas fluorescens, a potential bacterial antagonist to control plant diseases. J Plant Nutr — Aquac Int Sustainability — Water Switzerland — Ozone Sci Eng — In: Logsdon GS ed Slow sand filtration, vol 1. Nat Rev Microbiol — Hirayama K, Mizuma H, Mizue Y The accumulation of dissolved organic substances in closed recirculation culture systems. Hultberg M, Holmkvist A, Alsanius B Strategies for administration of biosurfactant-producing pseudomonads for biocontrol in closed hydroponic systems. Crop Prot — James, Becker JO Identifying microorganisms involved in specific pathogen suppression in soil. Annu Rev Phytopathol — Jarvis WR Managing disease in greenhouse crops. The American Phytopathological Society, St. Paul Google Scholar. New Phytol — Khalil S, Alsanius BW Dynamics of the indigenous microflora inhabiting the root zone and the nutrient solution of tomato in a commercial closed greenhouse system. Gartenbauwissenschaft — Google Scholar. Khalil S, Alsanius WB Effect of growing medium water content on the biological control of root pathogens in a closed soilless system. J Hortic Sci Biotechnol — Khalil S, Hultberg M, Alsanius BW Effects of growing medium on the interactions between biocontrol agents and tomato root pathogens in a closed hydroponic system. Biocontrol Sci Technol — Lee S, Lee J Beneficial bacteria and fungi in hydroponic systems: types and characteristics of hydroponic food production methods. Aquac Eng — Google Scholar. Lepoivre P Phytopathologie, 1st editio. Phytoparasitica — Aquaculture — In: Soilless culture: theory and practice. Elsevier B. Biol Agric Hortic — Org Agric — Procedia Environ Sci Int J Veg Sci Appl Agric Res — Google Scholar. Michaud L, Blancheton JP, Bruni V, Piedrahita R Effect of particulate organic carbon on heterotrophic bacterial populations and nitrification efficiency in biological filters. Glob Chang Biol 9, — PLoS One — Environ Chem Lett — Biomed Res Int Narayanasamy P Biological management of diseases of crops: volume 1: characteristics of biological control agents, Biological management of diseases of crops. Springer, Dordrecht. Canada N Am J Aquac — CO;2 Google Scholar. In: Ecological footprint in Central Europe. Can J Plant Pathol — Pagliaccia D, Ferrin D, Stanghellini ME Chemo-biological suppression of root-infecting zoosporic pathogens in recirculating hydroponic systems. Plant Soil — Microb Ecol — In: Conference and exhibition on soilless culture, pp 71—76 Google Scholar. Parvatha Reddy P Sustainable crop protection under protected cultivation. Curr Opin Biotechnol 22 2 — Rakocy J Ten guidelines for aquaponic systems. Aquaponics J —17 Google Scholar. Rakocy JE Aquaponics — integrating fish and plant culture. In: Tidwell JH ed Aquaculture production systems. Wiley, New York, pp — Google Scholar. Resh HM Hydroponic food production : a definitive guidebook for the advanced home gardener and the commercial hydroponic grower, 7th edn. Rosberg AK Dynamics of root microorganisms in closed hydroponic cropping systems. Rev Aquac — Ann Agric Sci — Arch Microbiol 1—8. Curr Opin Biotechnol — Soil Sci Plant Nutr — Sirakov I, Lutz M, Graber A, Mathis A, Staykov Y Potential for combined biocontrol activity against fungal fish and plant pathogens by bacterial isolates from a model aquaponic system. Water —7. Snoeijers SS, Alejandro P The effect of nitrogen on disease development and gene expression in bacterial and fungal plant pathogens. Trop Plant Pathol — Stanghellini ME, Miller RM Their identity and potencial efficacy in the biological control of zoosporic plant pathogens. Plant Dis — Google Scholar. Sugita H, Nakamura H, Shimada T Microbial communities associated with filter materials in recirculating aquaculture systems of freshwater fish. Summa Phytopathol — Takeda S, Kiyono M The characterisation of yellow substances accumulated in a closed recirculating system for fish culture. In: Proceedings of the second Asian fisheries forum, pp — Google Scholar. Aquaculture — Google Scholar. Thongkamngam T, Jaenaksorn T Fusarium oxysporum FB as biocontrol agent against plant pathogenic fungi in vitro and in hydroponics. Plant Prot Sci — Tu JC, Papadopoulos AP, Hao X, Zheng J The relationship of a pythium root rot and rhizosphere microorganisms in a closed circulating and an open system in stone wool culture of tomato. Van Der Gaag DJ, Wever G Conduciveness of different soilless growing media to Pythium root and crown rot of cucumber under near-commercial conditions. Eur J Plant Pathol — Van Os EA Comparison of some chemical and non-chemical treatments to disinfect a recirculating nutrient solution. In: International symposium on protected cultivation in mild winter climates: current trends for sustainable techniques, pp — Google Scholar. Plant Pathol — Environ Technol Rev — Water Switzerland —9. Acta Hortic. Whipps JM Microbial interactions and biocontrol in the rhizosphere. J Exp Bot — Wohanka W Disinfection of recirculating nutrient solutions by slow sand filtration. Environ Sci Pollut Res — Personalised recommendations. Cite chapter How to cite? ENW EndNote. Media with high water content and low content in oxygen e. Sutton et al. Podosphaera xanthii a. Pseudomononas solanacearum a. McMurty et al. Phytophthora infestans a. Solanum lycopersicum 1 ,. Calvo-bado et al. Evenhuis et al.

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