Rapid human population growth leads to substantial development in agriculture production. Thus, large amounts of synthetic products are used to meet the demand for increased agricultural production. However, heavy usage of chemicals, pesticides, and antibiotics creates a burden on the environment, destroys the micro-fauna and flora in the soil, and causes threats to animals and human health. Therefore, sustainable agriculture production has gained global interest. In many ways, the application of effective microorganisms (EM) plays a vital role in sustainable production and has been widely spread throughout the world.

The EM is a fermented mixed culture of naturally occurring species of beneficial microorganisms that includes photosynthetic bacteria, lactobacilli, yeast, and actinomycetes in an acidic medium. After the concept of EM was initiated, different fertilizer manufacturing companies developed EM solutions to enhance crop production. This is an area where research and development activities are also abundant for long-term and short-term crop production. Promoting germination, flowering, fruiting, and ripening in plants; improving the physical, chemical, and biological environments of the soil, and suppressing soil-borne pathogens and pests; enhancing the photosynthetic capacity of crops and nitrogen fixation; ensuring better germination and plant establishment, increasing the efficacy of organic matter as fertilizer; and accelerating the decomposition of organic waste are some examples where EM could be used to gain an economic advantage in crop production. In the commercial use of EM, it could be found under different brand identities.

EM is eco-friendly, safe, organic and contains active microbes. EM solution is different from all the other agrochemicals in activity and composition. It is not necessary to put on goggles, masks, or protective clothing when spraying effective microorganisms. At the same time, effective microorganisms never pollute water systems. EM is considered mainly of the synthesizing type, which imparts beneficial effects on agriculture and environmental processes by generating a wide variety of bioactive substances. Since EM is easy to decompose after use, it never pollutes groundwater. Instead, it purifies soil, groundwater, lakes, and rivers, thereby reducing environmental burdens. The effective microorganism is compatible with various methods of farming, regardless of their scale.

However, some experiments reported that EM gives the best results when a natural imbalance of microorganisms has occurred and, in situations where the natural microorganism population is balanced and agricultural inputs are available, the addition of EM does not make a significant difference. Another argument emerging by scientists is the fact that applying EM to soil alters the natural chemical composition of the soil, displacing native microorganisms and nutrients, which may be harmful to the survival of native plant species Thus, and more research should be directed towards this aspect.

Advancements in the EM concept have paved the path to substitute synthetic products. Achieving sustainability in agriculture production using EM is directed basically to reducing the production cost, maximizing the profit, and protecting the environment, human and animal health.

References
Higa, Teruo (2001) ‘Effective Microorganisms in the context of Kyusei Nature Farming: a technology for the future’, in Proceedings of the conference on greater productivity and a cleaner environment through Kyusei Nature Farming, pp. 40–43.

Olle, M., and Williams, I. H. (2013). Effective microorganisms and their influence on 47 vegetable production–a review. The Journal of Horticultural Science and Biotechnology, 88(4), 380–386.

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Coconut (Cocos nucifera ) is one of Sri Lanka’s three major export crops, bringing home a total revenue of US$537.62 million in 2014. Known for its great versatility, the coconut tree is one of the most important plants in Sri Lanka.

The Sri Lankan lifestyle has been inextricably intertwined with the Coconut tree, not just for the milk, water, and oil-giving nuts, but for the leaves, the trunk, and the fibrous husk that surrounds the coconut. There is no part of the coconut tree that goes to waste in a Sri Lankan household. There are three types of coconuts in Sri Lanka: tall coconuts, dwarf coconuts, and King coconuts.According to figures published in December 2018 by the Food and Agriculture Organization of the United Nations, it is the world’s fourth largest producer of coconuts, producing 2,623,000 tonnes in 2018. Because of the value of the coconut in Sri Lanka, it is named “Kapruka”, which means the crop gives every wish.

In all but the upper elevations of Sri Lanka, coconut palms are found. It is a demanding, sturdy, and light tree. In the triangle created by Puttalam, Kurunegala, and Gampaha, the coconut is primarily found. The Coconut-Triangle is the name given to the region in which these three settlements are located.

Coconut Whitefly (Aleurodicus cocois) damage
This insect is known in Sri Lanka by various names, such as powdery mildew, whitefly, and white bug. About 1 mm in length, this pest lives in herds, sucking the sap of various plants. In addition to coconut, the insect attacks plants such as bitter gourd, watermelon, snake gourd, belonging to the Cucurbitaceae and peanut, cowpea, and beans, belonging to the Leguminosae, also being affected. In addition, it acts as a carrier of viruses or fungi and causes huge damage. At higher temperatures, their activity is somewhat stronger.

This white-colored insect penetrates the leaflets of coconut seedlings and mature coconut trees and then damages the coconut plant by sucking the sap out of them. They belong to the phylum Arthropoda class and have four basic stages in the life cycle. On the underside of the leaves of the coconut tree, many stages of the life cycle of this insect can be seen with the naked eye.

Control of white fly damage
There are two methods recommended by the CRI to control the coconut white fly attack.

The first method is the physical method. In this method, manual removal has to be done. Application of pressurized water to wash away the underside of the leaves well also removes the white flies.

Because these white flies are drawn to yellow, using yellow polythene with grease applied is another strategy for population control.

The second method is the chemical method, and in this method, the application of recommended chemicals can be done. For instance, the application of a dissolved solution of 3g of Thiamethoxam or 20ml of carbosulfan or 2.5 g of an insecticide containing chlorantraniliprole in 10 liters of water, using a sprayer, thoroughly wets the underside of the leaves of the plant.

References
https://www.srilankabusiness.com/blog/multiple-products–made-from-coconut-tree.html
https://en.wikipedia.org/wiki/Coconut_production_in_Sri_Lanka#cite_note-2
https://en.wikipedia.org/wiki/Coconut_production_in_Sri_Lanka#cite_note-5

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Featured image – https://m.indiamart.com/proddetail/detergent-surf-for-palm-tree-and-coconut-trees-for-white-fly-effect-21836262973.html
Figure 1 –  https://www.srilankabusiness.com/blog/multiple-products–made-from-coconut-tree.html
Figure 2 – https://goodhands.lk/coconut-whitefly-damage-aleurodicus-cocois/

What are mushrooms?
Mushrooms are unique structures of fungi that belong to the Kingdom fungi, which also includes yeasts, moulds, and mildews. Fungi have been categorized under four major groups.

1. Zygomycota
2. Ascomycota
3. Basidiomycota
4. Deuteromycota

Most mushrooms belong to the Basidiomycota ,and aid in producing, storing of spores that would be used in reproduction. Mushrooms have been consumed by humans for thousands of years. Since the demand for these mushrooms has increased, commercial mushroom cultivation has started. In Sri Lanka, demand for edible mushrooms has increased in the last few years.
In Sri Lanka, growing mushrooms is primarily done at the household level as a small business. There are many mushroom growers in Sri Lanka. Even though there is a sizable market for high-quality mushrooms, most growers frequently fall short of the standards because they lack the necessary knowledge. If done properly, mushroom cultivation can be a lucrative business.

Commercially Cultivated Mushrooms in Sri Lanka

• Piduru Bimmal (Volvariella volvacea)
• Muthubeli Bimmal (Pleurotus ostreatus)
• Boththam Bimmal (Agaricus bisporus)
• Shitake Bimmal (Lentinus edodes)
• Abaloni Bimmal (Pleurotus cystidiosus)

Among these mushroom types, Muthubeli Bimmal is the most popular Mushroom variety and Piduru Bimmal are commonly cultivated.

Edible Mushrooms Native to Sri Lanka
Uru Paha Bimmal – Lentinus giganteus
Uru paha Bimmal is a mushroom species native to Sri Lanka. This mushroom species has the taste of Pork. Hence the name Uru (Pig) paha Bimmal. This species is the largest Mushroom in Sri Lanka. Uru paha bimmal grow naturally around the roots of large trees like Jack (Artocarpus heterophyllus). This species has shown promising results of growing under artificial environments. Apart from these varieties, some other types of mushrooms that naturally grow in Sri Lanka include Mawali Hathu, Indalolu, Monara Bimmal, and Kiri Bimmal.

Pest and the Disease Management in Mushroom Cultivation
Large-scale financial losses result from pest attacks on the mushroom industry. Particularly harmful insect species include Drosophila, which feeds on these mushrooms. When mushrooms appear transparent or decayed, these pest attacks are apparent.

Control Methods
Once these mushrooms have been infected, it is difficult to control the pests of mushrooms. So, it is really important to take actions to prevent the pest attacks from the beginning of the cultivation. Keeping the equipment used in Mushroom cultivation clean, avoid using same cultivation room to keep differently aged mushrooms, removing and destroying any infected bags from the cultivating area ,harvesting the mushrooms at correct maturity, only using sprayers to moist the cropping room without using hands, if the pest attack is severe, remove all the bags from the cottage and use a recommended insecticide to treat the infected area – keeping the cottage close for 24 hours after treating could be practiced.

Preservation of Harvested Mushrooms
As mushrooms contain more than 90% of water, they have less shelf – life. If mushrooms are kept in an open environment, these mushrooms can dry rapidly due to loss of water. This will also result in reduction of weight of mushrooms. So, it is really important to preserve these mushrooms immediately after harvesting.
Muthubeli Bimmal can be kept fresh in a cold place up to 12 hours after the harvest. This can be kept inside a refrigerator, packed in aerated polythene bags up to 2 – 3 days. To keep this species up to 4 -6 weeks, mushrooms can be boiled for three minutes and stored in a deep freezer.
Stripped mushrooms can be boiled with water vapor for 03 minutes and then sun dried to preserve for 06 months.
Piduru Bimmal is less preservable. It can be kept up to several hours after the harvest in a cold environment. Can be kept up to 24 hours in a refrigerator.

Characteristics of Poisonous Mushrooms
Poisonous mushrooms have a dark color and a strong aroma. One of the characteristics of poisonous mushrooms is that they deter insects.

Simple Tricks to Identify the Poisonous Mushrooms at Home
To identify poisonous mushrooms, one can perform easy tests at home. The mushrooms may be poisonous if the onions turn purple when cooked with them or if they stain the silver spoons black.

Advantages of Mushroom Cultivation
Good return on investment, availability of low-cost raw material, ability to start the cultivation within a small space, ability to start the cultivation with prevailing infrastructure facilities (Room inside a house), harvesting is possible in short duration of time.

References

https://agrislanka.blogspot.com

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Featured image – https://agri.pdn.ac.lk>dodangolla
Figure 1 – https://www.researchgate.net/figure.Mushroom-morphology
Figure 2 – https://en.m.wikipedia.org/wiki/File:Amanita_muscaria

Majority of the Sri Lankan families, including yours and mine, are facing an unprecedented food crisis. With the country’s acute malnutrition among children under 5 years, reaching 17%, Sri Lanka has secured the second highest malnutrition rate across South Asia, a position of shame and disappointment.

Many factors, including the Covid-19 pandemic, national issues such as poor governance and irrational policy making can be identified as major catalysts which have escalated this nutritional crisis.

Significant effects have been raised due to the continuous rising of food costs, which was reported as a 90.9 percent increase in July 2022 (Department of Census and Statistics – Sri Lanka). While a higher level of inflation is expected in the future, why has Sri Lanka’s inflation been so high and identification of the influence of the agricultural sector is of utmost importance.

In a broader perspective, Sri Lanka’s foreign currency shortage and bad credit reputation has resulted in continuous failures of purchasing and importing key agricultural imports such as fuel, fertilizer and pesticides. This in turn has led to almost halving of the gross agricultural production (BBC.com). While blames are being shared and thrown across, an important realization noted through this crisis was the heavy reliance on imports and unsustainable nature of Sri Lanka’s agricultural sector.

Although historically known to have produced enough rice to ship excess to Myanmar, today Sri Lanka is a recipient of rice donations from the same nation. There’s much to reflect and lament on where and what went wrong and even now it is not too late to take mitigatory actions.

Donations from friendly nations: Myanmar, China and India as well as global organizations such as the UN’s World Food Program play a vital role. Nevertheless, questions on their proper management and equivalent distribution exists in a major scale.

For short-term and long-term solutions, an in-depth analysis of the current and prevalent issues must be carried out and a systematic action plan must be implemented. This should be done while integrating the expert knowledge and advice of academics and researchers across Sri Lanka – frequently disregarded by all-knowing political factions.

Agriculture is of global importance and therefore, almost every day, a novel discovery inching us closer towards global food security, is being released. However, these require considerable investments and specialized training which is a heavy price to pay for a country already in crisis.

Therefore, search for feasible solutions that can be employed in a localized and short-term framework is of paramount importance.

1. Promoting urban farming. Farming in Sri Lanka has been concentrated in certain regions away from urbanization. Although it makes sense for large scale operations, small or medium scale farming within urban regions should be encouraged including individual households.

2. Improving existing infrastructure to facilitate easy transportation, distribution of agricultural products from farmer to consumer and minimizing mediator costs.

3. Reducing food wastage. Despite the ongoing crisis, food wastage by individuals and corporations is a significant problem. Focusing on demand vs. supply, and donation of excess daily produce can help feed many.

4. Providing specialized, ground-level support and guidance to farmers with available newest technologies and local discoveries.

5. Recruiting the private sector for aid, under the corporate social responsibility frameworks.

6. Raising public awareness of the ongoing crisis and creating a collective social impact via Scientific communication.

Although feasible solutions are available, without proper guidance or monitoring, it is difficult to achieve them. A national strategy with a clear set of objectives and goals is imperative if we are to overcome this crisis because, nutritional Crisis might not be your problem today, but it could be yours tomorrow.

References
http://www.statistics.gov.lk/
https://www.bbc.com/news/business-62990385
https://srilankabrief.org/sri-lankas-agricultural-scientific-community-predicts-substantial-yield-losses-in-agricultural-production-due-to-govts-new-policy/

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Poinsettia is a colorful blooming potted plant, in the Euphorbia family. It is a popular holiday plant especially used for decorations during the winter holidays in Europe and American countries. Poinsettia is more attractive because of its colorful bracts (leaves). Different colored poinsettias in the market are from different varieties. The Poinsettia flower is made up of bracts that look like a petal, but in the center, there are tiny yellow flowers called cyathia. The potted poinsettia has more branches and it grows like a small bush and it is an important feature in the market. They are usually produced through cutting propagation of the axial bud or terminal bud of vegetative stock plants. It is necessary to treat the plant with chemicals 6-7 times. Today all the commercial poinsettia varieties are planted with free branching phenotypes. The secret of this free branching is a result of the infection by phytopathogens known as Phytoplasma.

Phytoplasmas are a group of prokaryotes which are very small bacteria without a cell wall but covered by a membranous envelope. Phytopathogenic studies of various genes of phytoplasma suggest that they are descended from walled-bacteria in the Bacillus/Clostridium group. They are less than 1µm in diameter with a reduced genome greatly in size. Therefore, they lack enzymes needed for biosynthetic pathways. Thus, what should they do to obtain the necessary compounds? All known phytoplasmas infect plants and transmit through insect vectors and obtain necessary compounds from plants and vectors. Phytoplasmas are phloem-limited pathogens. In plants phytoplasma mainly lives in the sieve cells of phloem tissues. Therefore, phytoplasma transmission has been confirmed only through phloem-feeding insects. Phloem-feeding insects such as leafhoppers and planthoppers of the order Hemiptera are identified as vectors. Vectors acquire phytoplasmas passively during feeding and have a long time period of acquisition during feeding time to acquire sufficient phytoplasmas to establish in the vector body. It can take up to nearly three weeks. Once phytoplasmas are established, they will be found in most organs of the infected vector. Phytoplasma replicates in the salivary glands of vector insects. In addition, phytoplasma can be transmitted through vegetative propagation.

Phytoplasma diseases spread mainly in tropical and sub-tropical countries. The presence of phytoplasma is associated with a wide range of symptoms. Phyllody is the development of leaf-like growth in place of normal flowers. Some plants develop green color in place of normal flower color (green flowers) called virescence and witches' broom is an abnormal excessive proliferation of axillary shoots resulting in a broom-like growth. The other characteristic symptom is little leaves, the development of abnormally small leaves.

The proliferation of axillary shoots is useful in the production of poinsettia. Witches' broom symptoms are shown at the infection of poinsettia. The phytoplasma associated with poinsettia branching belonging to group 16SrIII-H produces more auxiliary shoots that have more than one coloured shoot with flowers. Therefore, some symptoms of phytoplasma are commercially important except for their negative impacts.

References
Pondrella, M.; Caprara, L.; Bellardi, M.G.; Bertaccini, A., Roll of Different Phytoplasma in Inducing Poinsettia Branching. Proc.10th IS Virus Disease Ornamentals, 2002, pp 170-176.

Assunta, B., Plants and Phytoplasma: When bacteria modify Plants. MDPI 2022, 11
Hogenhout, S.A., Plant Pathogen – Minor (Phytoplasma). Elsevier 2009

Kumari, S.; Nagendran, K.; Bahadur Rai, A.; Singh, B.; Rao, G.P.; Bertaccini, A., Global Status of Phytoplasma Disease in Vegetable crop. Frontiers in Microbiology 2019, 10

Bertaccini, A.; Oshima, K.; Maejima, K.’; Namba, S., Phytoplasma: Plant Pathogenic Bacteria-III, Chapter 2

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Introduction to biopesticides
Biopesticides are biological agents used to control pest populations.They include botanicals, pathogenic microbes such as fungi, bacteria, viruses, other natural enemies of pests such as parasitoids, predators, nematodes and semiochemicals.

Biopesticides can be divided into three major categories.

1. Microbial pesticides
These consist of microorganisms as the active ingredient. Microbial pesticides can control many kinds of pests. However, the active ingredient of the biopesticide is relatively specific for its target pest.
E.g., Bacillus thuringiensis: each strain of this bacterium produces a different mix of proteins that specifically kills one or few related species of insect larvae.

2. Biochemical Pesticides
These are naturally occurring substances that control pests by non–toxic mechanisms in contrast to conventional pesticides that either kill or inactivate pests.
E.g., Sex pheromones, various scented plant extracts that interfere with the mating behavior of pests.

3. Plant-incorporated protectants (PIPs)
This is where plants produce certain pesticidal constituents by themselves from genetic material that are inserted to the plant genome.
E.g., Scientists can extract the gene for the Bacillus thuringiensis (Bt.) pesticidal protein and introduce the gene into the plant genome. Thereby, the plant can manufacture the particular pesticidal protein that inhibit the pest when it feeds on the plant.

An insight to microbial biopesticides
In this category, the active ingredient is a microorganism that either occurs naturally or is genetically engineered.

The pesticide action may be from the organism itself or from a substance it produces. The most commonly used microbial biopesticides are the living organisms which are pathogenic for the pest of interest. They include,

(i) Biofungicides (E.g., Trichoderma, Pseudomonas, Bacillus)
(ii) Bioherbicides (E.g., Phytophthora)
(iii) Bioinsecticides (E.g., Bacillus thuringiensis)

The active ingredient of the microbial pesticide (which is a microorganism such as bacterium, fungus, virus, protozoa, alga, rickettsia, mycoplasma or nematode) suppresses pests either by producing toxic metabolites, competition, or various other modes of action.

An example for a microbial biopesticide; Bacterial biopesticides
Bacterial biopesticides are the most common form of microbial pesticides that function in multiple ways. Generally, they are used as insecticides, although they can be used to control the growth of plant pathogenic bacteria and fungi.

As an insecticide, they are generally specific to individual species of moths, butterflies, beetles, flies, and mosquitoes. To be effective, they must come into contact with the target pest and may require to be ingested. In insects, bacteria disrupt the digestive system by producing endotoxins that are often specific to the particular insect pest.

When used to control a pathogenic bacteria or fungus, the bacterial biopesticide colonizes the plant and crowds out the pathogenic species. The most widely used microbial pesticides are subspecies and strains of B. thuringiensis during its sporulation synthesizes crystalline infusions containing proteins known as endotoxins or Cry proteins, which have insecticidal properties.

Due to their high efficiency and safety in the environment, B. Thuringiensis and Cry proteins are considered as sustainable alternatives to chemical pesticides for the control of insects.

References
Ruiu, L. (2018). Microbial Biopesticides in Agroecosystems. Agronomy, 8(11), 235. https://doi.org/10.3390/agronomy8110235

What are Biopesticides? | US EPA. US EPA. (2022). Retrieved from https://www.epa.gov/ingredients-used-pesticide-products/what-are-biopesticides.

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Viruses are non-cellular agents that replicate inside host cells, often leading to disease in the host. Plant virus infections are associated with devastating losses in agriculture and threaten global food security. Viruses are responsible for nearly 50% of plant diseases accounting for an estimated annual economic loss of US$30 billion (Hilaire et al., 2022). Some sources attribute major crop yield losses of up to US$ 60 billion annually worldwide due to plant virus infections (Fingu-Mabola and Francis, 2021). However, not all viruses should be viewed in a negative light. As viruses are host-specific, there is potential to utilize them as bio-control agents against agricultural pests and pathogens. Furthermore, virus infection of plant endophytes has been linked to increased thermal and drought tolerance in plants. This article, therefore, aims to explore the nature of viruses’ pathogenicity in plants and their importance and applications in agriculture.

So what is a virus? A virus is an acellular infectious pathogen composed fundamentally of a ribonucleic acid (RNA) or deoxyribonucleic acid (DNA) genome encased in a protein coat known as the capsid. In addition, some viruses may have an outer envelope made of a membrane containing lipids and proteins derived from the host cell. Many viruses have spike proteins on the capsid or on the envelope which help the virus bind to receptors on the host cell. The infectious form of a virus is called a virion. Plant viruses, also known as phytoviruses, generally come in the form of helical (roughly elongated) or icosahedral (roughly spherical) shaped capsids (Gergerich and Dolja, 2006). While spherical viruses are relatively small (diameter ~30nm), elongated viruses can be significantly bigger: tobacco mosaic virus (TMV) is 300 x 18 nm, and some filamentous viruses can reach the length of ~2000nm (2µm) (Gergerich and Dolja, 2006). A typical plant cell in comparison is ~50µm. Most phytoviruses contain an RNA genome, and DNA phytoviruses are rare (Gergerich and Dolja, 2006).

Why are viruses harmful to the host? Plant viruses are obligate, biotrophic parasites. The virion can penetrate the host cell mainly via wounds caused by damage to the cell wall or through insect vectors. Inside the cell, the viral genome leaves the capsid and takes over the host cell machinery to conduct transcription and translation producing new viral nucleic acids and proteins. New virions are assembled in the plant cell followed by the release of mature virions out of the cell to infect new host cells (Figure 1). In plants, virions can enter neighboring cells via the plasmodesmata (cell-to-cell movement) and can move to other parts of the plant in the phloem tissue (long-distance movement) (Gergerich and Dolja, 2006). The virus infection leads to adverse effects on plants such as stunted growth, abnormal flower and leaf formation, ring patterns and bumps on the foliage, necrotic spots, mosaic, and mottling of the leaves (Figure 2). This can have a severe impact on crop yields.

As negative an impact as most virus infections may have on plants, the relationship between virus and host can be blurred. Some viruses such as pararetroviruses in tomato plants are integrated in an inactive state within the genome of the host cell for long periods and will only become active under stress; the presence of an inactive virus in the host for an extended time may act as a method of immunization and give the host a selective advantage in fighting against other pathogens (Roossinck, 2015). Meanwhile, some viruses have mutualistic impacts on plants such as counteracting the effects of abiotic stress. In Yellow Stone National Park where geothermal soils can reach temperatures greater than 50˚C, one species of grass that is colonized by a fungal endophyte infected by the virus allows the plant to survive hot temperatures (Roossinck, 2015)! Greenhouse studies have also shown that some virus infected plants have conferred drought-tolerance to plants (Roossinck, 2015). Further study of this phenomena may have useful applications in the development of heat- and drought-tolerant plants that can survive global climate change.
Some plant viruses may also help fight against biotic stress. For instance, studies have shown that white clover mosaic virus infection helps the plant deter fungus gnats and zucchini yellow mosaic virus downregulates the production of volatile compounds in plants that attract beetles; as beetles are vectors of bacterial wilt, the viral infection has protected the plant from wilt disease (Roossinck, 2015). Studies are also being conducted on using bacteriophages (viruses that infect bacteria) as an agent to control bacteria-borne diseases in plants.

In considering this, it is highly important to thoroughly study phytoviruses to understand the nature of plant-viral relationships and explore applications of this knowledge to increase crop yields.

References
Carbonell, A., García, J.A. et al. (2018). eLS Plant Virus RNA Replication, accessed https://www.semanticscholar.org/paper/eLS-Plant-Virus-RNA-Replication-Carbonell-Garc%C3%ADa/85f49c32434c48dce5dbe0eec5d7b80e0af810c9
Fingu-Mabola, J.C. and Francis, F. (2021). Aphid-plant-phytovirus pathosystems: influencing factors from vector behaviour to virus spread. Agriculture, 11(6), https://doi.org/10.3390/agriculture11060502.
Gergerich, R.C. and Dolja, V.V. (2006) Introduction to plant viruses, the invisible foe. The Plant Health Instructor, DOI: 10.1094/PHI-I-2006-0414-01
Hilaire, J., Tindale, S., Jones, G. et al. (2022). Risk perception associated with an emerging agri-food risk in Europe: plant viruses in agriculture. Agriculture and Food Security, 11(2), https://doi.org/10.1186/s40066-022-00366-5 .
Roossinck, M. J. (2015) Move over, bacteria! Viruses make their mark as mutualistic microbial symbionts. Journal of Virology, 89(13), pp. 6532-6535.

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Featured image: https://p4.wallpaperbetter.com/wallpaper/374/292/34/medical-virus-wallpaper-preview.jpg
Figure 1: Carbonell, A., García, J.A. et al. (2018). eLS Plant Virus RNA Replication, accessed https://www.semanticscholar.org/paper/eLS-Plant-Virus-RNA-Replication-Carbonell-Garc%C3%ADa/85f49c32434c48dce5dbe0eec5d7b80e0af810c9

Figure 2 : University of Maryland Extension (2018-2020) https://extension.umd.edu/sites/extension.umd.edu/files/styles/optimized/public/2021-06/HGIC_flowers_peony_virus-symptoms_CC_600.jpg?itok=EEPJsGqA

Climate is defined as the weather conditions prevailing in an area over a long period of time. Global climate change is the long-term alteration of weather patterns in the planet that results in elevated temperature, carbon dioxide (CO2) levels, changing rain and wind patterns, melting of glaciers and rising seawater levels. Climate models predict that the global average temperature will rise by 0.2 ˚C in the next two decades in every climatic zone including tropical, temperate, and polar regions.
Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create energy in the form of sugar and produce molecular oxygen as a by-product. The carbon cycle in the earth is driven by this process of photosynthesis. This reaction happens mainly in green plants and in some other photosynthetic microorganisms. There are mainly two steps in the photosynthetic process. The first one is the light-dependent reaction where energy is stored in ATP (Adenosine triphosphate) and NADPH (Nicotinamide adenine dinucleotide phosphate) while producing oxygen (O2) as a by-product. The next step is independent of light and is called the Calvin Cycle where sugar molecules are formed by fixing CO2. Furthermore, there are three types of photosynthetic mechanisms called C3 (in cotton, spinach, soybeans, etc.), C4 (in maize, sugarcane, sorghum, etc.), and CAM (in cacti, pineapple, etc.).

CO2 is a greenhouse gas that absorbs longer wavelength radiation and traps heat around the earth’s surface. This phenomenon is known as the greenhouse effect. But when high CO2 levels are present in the atmosphere this eventually leads to excessive global warming.
Carbon dioxide levels today are higher than at any point compared to the past. The levels are rising mostly because of the burning of fossil fuels by humans. The last time the atmospheric CO₂ amounts were this high was more than 3 million years ago. Therefore, we are going back to where plants or small algae began photosynthesis. At the beginning of life on earth, the oxygen concentration was very low in the atmosphere. C3 photosynthesis is thought to have arisen at this time.
The majority of the plant species use C3 photosynthesis in which the first and most stable carbon compound containing three carbon atoms is produced. That’s why it is called the C3 mechanism. The RUBP (Ribulose 1,5-bisphosphate) carboxylase enzyme which catalyzes carboxylation in the Calvin cycle has evolved in the primeval pre-photosynthetic atmosphere which contained high CO2 and no O2. Therefore, this climatic condition is favorable for plants to photosynthesize more efficiently and grow faster which leads to high crop productivity. Under well-watered and highly fertilized conditions, most C3 plants grow about 30% faster when the CO2 concentration reaches 600 – 750 ppm range but a little or no increased growth is seen in C4 plants which fix carbon dioxide into a 4 carbon compounds in order to enter the C3 or Calvin Cycle.
If CO2 concentration continues to increase at this rate, after a particular level plant photosynthetic rate will become limited due to the increase in atmospheric temperature. Under high-temperature conditions, plants tend to close their stomata (microscopic openings in the epidermis of leaves that facilitate gas exchange) to prevent desiccation. In the daytime, photosynthesis happens and thereby CO2 levels are depleted inside the photosynthetic cells and are not restored as stomata are closed. In such situations, the Rubisco enzyme binds with oxygen and leads to a phenomenon called photorespiration. It results in the release of CO2 with the utilization of ATP. This is energetically costly and a wasteful process that happens in C3 plants. Under elevated CO2 levels and high temperature, C4 plants are benefited since they are adapted to warm and high-temperature environments. These plants effectively maintain the CO2 levels in their photosynthetic cells and are adapted to prevent photorespiration.

Even though CO2 is much more important in photosynthesis and increases the rate of reaction up to a certain level the nutrients, and other factors act as limiting factors for the photosynthetic process. Therefore, the photosynthetic rate quickly becomes constrained by the less nutrient availability. Soil is eroded due to the low vegetation cover in lands and most of the nutrients are leaching out from the soil and it becomes poor in nutrients. The presence of pollutants in the atmosphere and low-level ozone can also indirectly reduce the net photosynthetic rate.
A better understanding of the above mentioned phenomena is crucial in studying natural ecosystems, in conserving a balanced ecosystem and in providing high crop productivity to feed the rising human population. If the above mentioned phenomena continue to happen in the future, the C4 and CAM plants may be benefited except the C3 plants even though C4 and CAM mechanisms are more energetically costly than the C3 mechanism. Since most of the plants on the earth are C3 plants, change in global climate patterns has a major influence on the plant community and their survival. Therefore, it is required to minimize these climatic changes while improving plants to adapt to this changing environment. To protect plants from climate change, personal action is more important than ever. Practices such as organic farming, eating less meat, producing clean energy, or even less use of vehicles can help save the planet from climate change and ensure the survival of plants that help us survive on earth.

References:
https://www.nationalgeographic.org/encyclopedia/climate-change/
https://scied.ucar.edu/learning-zone/climate-change-impacts/predictions-
Plant Physiology and Development by Eduardo Zeiger, Lincoln Taiz, Ian Max Moller, Angus Murphy – sixth edition.

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