Control Over Plant Disease in Organic Fruit Farming: Critical Review Paper Assessment 2 Answer

Control over plant disease in organic fruit farming

Assignment 2: Critical review paper (Control over plant disease in organic fruit farming)

Introduction

Organic farming (OF) has been of increased importance in recent times, especially fruit farming. Through this assignment, the purpose is to understand the control over plant disease in organic fruit farming. Globally, organic agriculture (OA) has substantially increased over the years, it has recorded the 10% per year growth in many countries (Reeves, 2018). By 2018, more than 2 million certified organic producers would have started to use the 43 million hectares of certified organic agricultural land (Zaccardelli, 2018). To control the plant disease, in organic fruit farming production the limitation is to use no chemicals, absence of synthetic pesticides, and low fertilizers, the main focus remains on using the friendly ecosystem ways to improve the health of the plants (Zheng, 2019). While using organic crop practices, it is crucial to have the environment-friendly ways to overcome the plant diseases in comparison to the conventional crop production on the agroecosystem (Zheng, 2019). 

 Aim 

The aim is to control plant diseases and improve management practices in organic farming systems (OFSs). It is crucial to understand the differences between soil-borne and airborne plant diseases within organic fruit farming, such as the fungal, bacterial, viral, and nematode growth and how to eradicate the problems naturally. 

Principles

The organic practices focus on the organic farmers to manage diseases and the principles behind the disease management, The principle practice is to overcome the disease management in organic farming and to manage the biological diversity. The main important step is to improve the soil health conditions through the various steps such as the balanced crop rotations,  by using the nitrogen-fixing, cover crops practices and how using the methods of intercrops along with the manure consisting of compost, and reductions in soil tillage (Costa, 2019). 

Plant disease difference in between the organic versus conventional agriculture

Root Diseases

Ventura (2019) has mentioned in his literature that the root diseases are the soil-borne pathogen which thrives due to the constant interaction between the pathogens and saprophytic microorganisms found in the soil beneath the root surface. In comparison to conventional traditional agriculture, it is a cumbersome process to control the root diseases. It is crucial to consistently control the root diseases in organic farming and even ensure to maintain soil quality and health (Wöhner, 2019).

Soil health and root disease

Usha (2019) emphasizes that while practicing fruit farming through organic farming, it is an essential way to focus on the soil health characteristics and control the plant disease.  The main factor is the management practices and how it is relevant for the promotion and maintenance of soil health and suppressing the root disease. Van Bruggen (2016) mentions an alternative characteristic of soil health, which is to maintain a high consistency of good soil structure, composition, and maintaining a high capacity of water holding soil properties. In comparison, controlling of the root disease, the main problem is in the drainage capacity and to include balanced nutrient cycling, and having an adverse effect on pathogen and pest populations. Thurston (2019) has critically evaluated that soil health is analogous to the ecosystem health system. Soil enrichment is part of the biological diversity, so it is essential to preserve the richness of the soil and minimize the environmental impact by using low chemicals. Thompson (2018) from his literature review has helped to understand on how to manage the root disease, the management tactics which aims to control the carbon and nitrogen sources, and also preserving oligotrophic conditions which can help to stabilize biological communities, further the practice of the stable soil community, using the practice of the soil tillage should be maximized, however here, the challenge lies in the no-till farming without the herbicides.

Tesfay (2017), in his literature, mentions organic farming, the soil richness is the key to suppress the root disease. It is argued, that in organic farming practices, through the general and pathogen-specific management practices, it can help to control the root diseases. Similar to the findings, Temple (2020) has emphasized on general suppression using biological factors, like microorganisms, and mixing it with the physical-chemical factors like nutrient and energy supply. The techniques help to control the growth of the pathogen that covers the soil and the root surface. The use of pathogen-specific suppression techniques is used during the specific interaction between the plant pathogen along with the antagonist condition like antibiotic producer or parasite, which is a reoccurring process which can be used in the monocropping situations. The use of the pathogen can be used during the suppression stages that are likely to control the organically managed soils and in accordance with the fruit types.

Root and foot diseases in monocotyledonous field crops

Stone (2017) has examined in his journal, how organic farming, in comparison to conventional farming, shows similar soil characteristics, however, there is less likeliness of the root disease found in the organic farming system. Skidmore (2019) provided instances from his literature, such as there are lower incidences of Fusarium infections (Fusarium graminearum or Fusarium culmorum), which is due to the higher control over the soil biodiversity and lower nitrogen contents and managing the organically managed soils. Reeve et al (2019) mention organic farming is a method to consistently maintain nutrients that can help to increase the pathogenic and antagonistic Fusarium species. The use of nonpathogenic Fusarium species is found to be dominant over pathogenic ones within the organic farming, the Fusarium foot rot (F. culmorum) along with the snow mold (Fusarium nivale), showing her the eyespot (Pseudocercosporella herpotrichoides) and also experiencing the eyespot (Rhizoctonia cerealis) that are likely to the total nitrogen application rates (Pylak, 2019). Take-all (Gaeumannomyces graminis) incidence that would be dependent on the converted organic fields in comparison to the longer-term organic fields. It would consistently result in the temporary initial increase and the high likeliness of the monocropping (that would be due to the suppression) to crop rotation (Orzali, 2017). 

Disease Cycle

Symptom–The root sign shows the true sign and symptoms of the disease. The roots can be diagnosed with diseases. The Syndrome is when the organic fruits get the disease would show a variety of the valuable signs/symptoms such as the rotten seeds or the interior damage. The Spore is observed to be minute propagating unit creating the more new individuals of the same species. Inoculums–would be seen as the infectious material or portion, and there would be the disease. Primary inoculums–is observed during the summer stage showing inoculums that begins indicating the disease within the field and surviving on a favorable condition it would eventually cause more infection. In the Secondary inoculums stage, during the disease development stage, a pathogen can also enter during the crop of spores/infective bodies causing a secondary infection.  

Controlling Disease in Organic Farming

General Considerations

Lamont (2017) mentions that in organic farming, the importance of disease management is different as the management practices are more focused on preserving the ecosystem's health.  Another essential identification is the internal stability is how to preserve the agroecosystem and preserve biological diversity. The organic growers depend on identifying the cultural plant protection methods, and how to use the sanitation, organic soil amendments, ability to have the lengthy crop rotations along with the reduced tillage and ensuring a timely efforts that can help to bring out the best of the proper timing of crops, crop and cultivar selection, intercropping, and cover cropping. Kumar et al (2018) mention that depending on the increased habitat diversity the importance of the natural pest and disease control, such as using the breed of intercropping along with the planting of trees, shrubs, wild grasses, and the use of the flowering plants can help to control the situation. It is argued, the genetically modified organisms (GMOs) can eventually be used for the gene manipulation and further avoid the genetic uniformity which can help in controlling the pest and disease outbreaks.

Holb (2016) examines methods in his literature, such as how to preserve and control plant disease management in organic farming and to control the pathogen incision, minimizing the spread and to control the biological invasions in the natural ecosystem. The best way to have the control tactics for disease management: such as how to (a) minimize initial inoculum, (b) identifying the minimized techniques to build a suitability control of the host and how to have the environment free from infection along with the reproduction, and (c) curative methods which would control the spread.

Minimizing Initial Inoculum

Gonzálvez (2018) emphasizes on how to minimize inoculum.  Initial inoculum can be controlled through removing infected plant materials and the best step is to disinfect the soil. The strategy of diagnosing pathogen entry in the crops is by integrating effective ways. Such as how to disinfect and control seeds and fruit planting material’s disinfestation, and prevent the entry of pathogens in a crop, for example, by disinfecting seeds and fruit planting materials.

Sanitation

Frey et al  (2016) emphasis on organic farming including inoculum can be observed in the vineyards and orchards and how to control the diseased branches. The residues would be eventually removed from the greenhouses. The use of the branches and residues can be used as compost, instead of burning, which would help to reduce the CO₂ emissions causing more harm by getting deposited as carbon in the soil. The methodology such as the covering or removing cull piles and using the volunteer plants and alternate hosts for pathogens, for example, the P. infesting has been one of the initial inoculum control.

Soil disinfestation

Cruz et al (2016) mention soil disinfestation techniques to be useful in organic agriculture, during the stages of flooding, soil steaming, and while using the polarization, anaerobic (or biological) along with the soil disinfestation (ASD), and biofumigation. Holb (2016), mentions that through the flooding process, it can help to moist the area and to control the infected diease areas. By using the soil steaming method, it can help to control the plant-parasitic nematodes and/or root pathogens used during the limited rotation method, by placing high-value crops in greenhouses. Gonzálvez (2016) mentions using the streaming method, as an effective way to kill all heat-sensitive plant and also help in controlling the pathogens, nematodes, along with the weeds. The method the steaming method goes inside in-depth and checks the soil microbial and preserves essential fauna. 

Frey et al  (2016) indicate, how the soil polarization an effective method of moistening the soil, which is done through the UV-resistant plastic exposed to the sunlight exposure for a few weeks. Subsequently, to control the plant-pathogenic fungi, bacteria, and nematodes, is done through the heat-tolerant fungi and viruses. The pathogens are highly sensitive when the temperatures increases (45–55°C). The use of the polarization effect can help to control the isothiocyanate-producing residues done through the brassica crops into the soil. Cruz et al (2019) have supported the use of the method, by mentioning that the pathogens can face the direct heat effects and have opinioned that the plant growth is due to mineral nutrients enrichment while doing the soil tilting process.

For ASD, the common goal is to preserve the fresh organic material within the soil when moistened and to compress it in the airtight plastic for 3–6 weeks. It would help in the proliferating bacteria and the methodology is when the depletion of the available oxygen would lead to anaerobic bacteria getting decomposed and causing the source of carbon. Due to the toxic products, such as the use of the alcohols, aldehydes, organic acids along with the volatile compounds, it can help to accumulate soil pH levels. The depletion causes a reduction in the survival of soil-borne pathogens. The procedure to deplete oxygen would impact the anaerobic bacteria such as Bacillus and Clostridium spp causing the tough condition to survive and causes the pathogen inactivation (Alwanney, 2017). Due to the ASD results, it would impact and control the soil-borne plant-pathogenic fungi, bacteria, and nematodes Rhizoctonia, Fusarium, Verticillium, Sclerotinia, Phytophthora, Ralstonia, Meloidogyne, and Globodera spp., and affect the weeds. Due to the changes experienced in the microbial communities characteristic, it would cause a general disease suppression (Boiu-Sicuia,  2017)y. Depositing the soil steaming and using the method of chemical soil disinfestation, can help in the biological vacuum, by impacting the conduciveness to reintroduced soil-borne pathogens.

The use of the Aerobic soil disinfestation; can help to work over the biofumigation leading to organic amendments to the soil, and even understanding the volatile compounds controlling the toxic soil microorganisms. While using green manure crops, the impact of glucosinolates, mainly Brassica spp., has been one of the effective ways. Due to the tissue decomposition, the problem of the hydrolysis can lead to highly toxic compounds, and use it within the organic cyanides, nitriles one of the essential steps for the thiocyanates causing control over the fungistatic or biocide properties. The use of application-based animal-derived residues can lead to high nitrogen, by using the manure or compost, during the production of ammonia gas, and controlling the toxic element for the pathogens and nematode pests.

Prevention of entry of pathogens in organic crops

Bonanomi (2018) has mentioned that through the consistent use of the seeds and planting materials, it would be helpful to create the organic crop production (approved by the certified organic sources). Through the organically produced seeds, it can be extracted through the fruits by deriving the natural means, such as the fermentation. Costa et al (2019) mention the use of chemical seed treatment after extraction is not permitted as the substitute method used here is of the seed treatment methods which are unlikely to be used. The three main seed treatment methods are identified as (a) physical methods, (b) treatment that can be done over the plant or microbial extracts, along with using the method of (c) seed coating one of the biological control agents (Frey, 2019). The use of the physical methods, such as hot water along with using the steam treatment  can help to control any impact over the drying. The use of the various seed can be done by sorting through machines that can reduce or eliminate the immature or diseased seeds. Through the several bio-control agents and even using the plant extracts, the commercially available methods can treat organic seeds that go against the fungal along with the bacterial contaminants.

Fruits and the propagated plants, for example, tomatoes and strawberries, can also help to work over the certified planting materials. Hewavitharana (2018) mentions that the organic growers face the problem of black scurf on strawberries (R. solani) which can be reduced through the seed tubers sorted in their farm. By using the certified seed tubers it would help to reduce the Rhizoctonia disease to decline over the organic farming (Gonzálvez, 2018). 

Temporal and Spatial Isolation

By using the temporal host plants the purpose of overcoming the barrier can go against the accumulation of pathogen propagules.

Temporal isolation

The damage done by the disease spread can be controlled by planting the fruits and adopting the ways of the maturing cultivars, and ways to combat the pathogen involved. Planting during the stages of heavy aphid flights can help to reduce the diseases and control in the given period.  

Crop rotation can be done during the temporal isolation of ways as a step to prevent inoculum buildup. The natural decline of pathogens can exist in host crops. Through the organic rotations, the use of the multiyear grass ley can be used instead of grass-legume ley at the stages of planting and maintaining healthy soil. By using the crop rotation the disease development can be controlled. The cover crops method is also a productive way to control nitrogen fixation. It works while reducing the nitrate leaching; and ways to control the chance of disease outbreaks along with minimizing the nematode damage within the cash crops (Hewavitharana, 2018)

Spatial isolation

Kumar et al  (2018) identifies using the spatial separation and identifies the pathogen which remains in the susceptible host plant. The control of the pathogen can be done by the planting barrier crops around the specific plants which would help in no susceptible crops to exist in between the susceptible ones.

Plant resistance

Many organic farmers also prefer to use open-pollinated cultivars to hybrid, and the method helps to provide a susceptible way to control certain diseases. It is a method to channelize the open-pollinated varieties to work over the genetic variation in comparison to the hybrids (Frey 2019). 

The aerial environment

Mohammed (2019) mentions that many foliar diseases grow in moist or humid conditions. Through the organic management and by providing the air and light conditions, it can help to reduce any sort of relative humidity that can result in thinning, pruning, leaf plucking conditions, and removal of the weeds. Other alternative steps like the wider planting distance, by planting parallels and facing in the direction of the wind (Hewavitharana,2019).

Curative control of pathogens in organic crops

Curative control techniques are used to control the check over pathogen within the crop. To integrate and use the effective spraying technology is a natural way of using an active agent: bio-control microorganism’s method along with the metabolites for better plant extracts or fungicide

Conclusion

To conclude, organic farming practices are the identification of general and pathogen-specific management practices that can help to control the root diseases. Through the general suppression uses the biological factors, and such as the microorganisms, along with combining with the physical-chemical factors, that includes the nutrient and energy supply. The techniques help to control the growth of the pathogen that covers the soil and the root surface. In comparison to the conventional traditional agriculture, it’s a cumbersome process to control the root diseases. It is important to consistently control the root diseases in organic farming and even ensure to maintain soil quality and health. The practice is to overcome the disease management in organic farming and to manage the biological diversity along with consistently focusing on improving the soil health conditions through the various steps such as the balanced crop rotations,  by using the nitrogen-fixing, cover crops practices and how using the methods of intercrops along with the manure consisting of compost, and reductions in soil tillage. The other is the pathogen-specific suppression techniques that have a specific interaction between the plant pathogen along with the antagonist such as the use of the antibiotic producer or parasite.