36. Whip Smut of Sugarcane and Their Control

 Sugarcane

Introduction:

    Sugarcane is a valuable crop for growers as it serves as the primary source of white crystal sugar, and also provides alternative sources of sugar such as 'gur' and 'khandsari' (brown sugar). In addition, sugarcane tops can be used as cattle fodder, bagasse and leaf trash can be used as fuel, and the stubble and roots can serve as organic manure. Crop residues can also be utilized for mulch and compost. It is worth noting that sugarcane leaves are also used as a substrate for growing edible mushrooms.

    In Pakistan, sugarcane cultivation faces numerous challenges, including significant losses caused by various diseases. Over 50 diseases have been reported in sugarcane, with fungi, bacteria, viruses, and nematodes causing the most damage. The extent of losses varies depending on the crop variety and location, and cannot be ignored, neglected, or taken lightly as they can significantly impact the crop. These diseases can affect different plant parts, and their occurrence is influenced by a range of factors such as geography, weather, and time. Symptoms or signs of the diseases raise a concern about their potential effects on the quantity and quality of the sugarcane crop.

    Sugarcane, a crop grown in over 120 countries on around 26.27 million hectares, is the largest commercial crop globally. It yields approximately 1.90 billion tonnes worldwide, providing 80% of the world's sugar. The crop produces hundreds of tons of green matter per hectare annually, giving 75,000 million calories. However, sugarcane takes 12-14 months to mature and harvest, making it vulnerable to many biotic and abiotic factors, such as pathogens and insect pests that can reduce production by up to 20%. Fungal pathogens, in particular, pose a significant challenge, with over 100 fungi reported to cause sugarcane diseases.

Whip Smut of Sugarcane

Causal Organism:

    The fungal disease, known as smut, is attributed to Ustilago scitaminea. The fungus infects sugarcane plants via buds present on erect stems or sprouting buds in the ground. Once inside, the fungus establishes itself near the plant's growing points or meristems.

Symptoms:

• Sugarcane smut is identifiable by a black, whip-like structure that replaces the spindle leaf and grows from the sugarcane plant's growing point. Abnormal whips, sometimes containing flower parts, can also develop.
• The whips are produced in shoots arising from infected cane cuttings, contaminated soil, or side shoots from mature stalks. 
• The thin membrane of the whip eventually ruptures to release a mass of black spores, leaving behind a straw-colored core.
• Before whip formation, the youngest leaves undergo shortening and crinkling. 
• Infected plants tend to be stunted, and individual stalks appear thin and grass-like.

Disease Cycle:

    Sugarcane smut spreads through teliospores produced in the smut whip found in soil or on plants. Teliospores germinate in water and produce promycelium, which undergoes meiosis to form four haploid sporidia. The fungus is bipolar, producing two different spore types that must mate to create a dikaryon that infects sugarcane's meristematic tissue by penetrating bud scales. The fungus grows within the tissue, inducing flowering structures that it colonizes to produce teliospores. These structures transform into a whip-like sorus, covered by a silvery peridium that peels back to expose black-brown teliospores. These spores disperse via wind and repeat the cycle. Teliospores are reddish-brown, round or subovoid, smooth to moderately echinulate, and 6.5-8 um. Susceptibility to S. scitamineum populations in each area should be tested before distributing sugarcane cultivars.

Spread or Transmission:

    Sugarcane smut is mainly transmitted via wind-dispersed spores or by planting contaminated or infected cane cuttings. Typically, spores spread over short distances, up to 10-15 meters, but they can travel many kilometers during strong winds or cyclones. Spore transport on machinery and shoes is also feasible.

    Moist soil can support spore survival for only 2-3 months, whereas dry soil or other arid environments can sustain them for longer periods. The fungus remains viable within infected sugarcane plants as long as the host plant is alive, as it requires a living plant to produce spores.

Control:

1. It is advisable to avoid using sets from sugarcane plants affected by smut for planting.
2. Seed sets can be disinfected by immersing them in a solution of 0.1% mercuric chloride or formalin for 5 minutes, followed by covering them with a moist cloth for 2 hours. Other effective chemicals available in the market can also be used.
3. Internal infection can be eliminated by exposing sets to hot water treatment at 52°C for 18 minutes.
4. Sugarcane plants affected by smut should be uprooted and burned before the spores burst.
5. It is recommended to avoid ratooning of crops affected by the disease.
6. Practicing suitable crop rotations with non-host crops can help in controlling the disease.
7. Planting sugarcane in healthy soil is essential to avoid infection.
8. Where the disease is prevalent, it is advisable to use dry sowing for the crop.
9. Autumn planting of sugarcane should be avoided.
10. Encouraging the use of resistant varieties is recommended to help control the spread of the disease.

References:

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4. Agronomy and its Importance

 Agronomy and its Importance

Agronomy:

    Agronomy is the science and technology of producing and using plants by agriculture for various purposes, such as food, fuel, fiber, chemicals, recreation, and land conservation.

    It has become an integral part of agronomy to study plant genetics, plant physiology, meteorology, and soil science. In this field, a combination of sciences is applied, such as biology, chemistry, economics, ecology, earth science, and genetics. The majority of agronomists work with crops that are grown on a large scale (e.g., small grains) and require a relatively low level of management. There are several factors that agronomists study about crop plants, including yield, diseases, cultivation, pest and weed management, and sensitivity to factors such as climate and soil. Plant breeding and biotechnology are two areas of specialization for agronomists. 

Father of Agronomy in the World:

    Pietro de'Crescenzi is considered the father of agronomy.

Father of Agronomy in Pakistan:

    In Pakistan, the Father of Agriculture is Dr. Abdul Rashid.

Principles of Agronomy:

These are the following 7 are given below:

1. Sustainable Agriculture:

    Sustainable agriculture is a type of farming that aims to meet the needs of the present generation without compromising the ability of future generations to meet their own needs. It is a method of farming that focuses on the long-term health of the land and its ability to produce food and other resources.

    Sustainable agriculture practices typically include minimizing the use of synthetic fertilizers and pesticides, rotating crops, conserving soil and water resources, and promoting biodiversity. This approach emphasizes the use of natural and renewable resources, such as crop rotation, cover cropping, and organic fertilizers, to maintain soil health and fertility, reduce erosion, and enhance ecosystem services.

Characteristics: 

• Conservation of natural resources: Sustainable agriculture aims to minimize the use of non-renewable resources such as fossil fuels, synthetic fertilizers, and pesticides, and instead prioritize the use of renewable resources such as crop rotation, cover cropping, and natural fertilizers. 
• Integrated pest management: Sustainable agriculture practices prioritize the use of natural and biological methods of pest management such as crop rotation, planting diverse crops, and the use of natural predators to control pests, rather than relying on synthetic pesticides that can be harmful to the environment and human health.
• Crop diversity: Sustainable agriculture emphasizes the importance of crop diversity to reduce the risk of disease and pest outbreaks, increase soil fertility, and promote biodiversity. 

Techniques:

    Here are some sustainable agriculture techniques commonly used in modern agriculture:

• Conservation tillage
• Crop rotation
• Cover cropping
• Intercropping
• Agroforestry
• Integrated pest management
• Organic farming
• Precision agriculture

2. Cropping system:

  A cropping system is a planned sequence of crops that are grown on a particular piece of land over a period of time. It involves the deliberate selection and rotation of crops to optimize the use of soil, water, and other resources, and to minimize negative environmental impacts such as soil erosion and nutrient depletion. A cropping system can also help to manage pests and diseases, and increase the overall productivity and profitability of the farm.

Objectives:

• By increasing the area of cultivation.
• By increasing productivity.
• To increase the production per unit of time.
• To increase the production per unit space.
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3. Cropping scheme:

   It is a specific plan or strategy for managing crop production over a period of time. It involves the selection and arrangement of crops in a sequence, as well as the timing of planting, harvesting, and other cultural practices.

    A cropping scheme is typically designed to maximize the productivity of a particular piece of land while minimizing the negative impacts on soil, water, and other natural resources. This can be achieved through crop rotation, intercropping, cover cropping, and other techniques that promote soil health, nutrient cycling, and pest management.

Principles: 

• The area below construction and layout.
• Several plots.
• The selection of plants relies upon the scenario of the farm.
• Facilities to be had at the farm.
• The area below man or woman plots.
• The area allocated to plants for calculation of cropping depth and rotational depth.

4. Crop rotation: 

   Crop rotation is a farming practice where different crops are grown on the same land in a planned sequence over time. It involves alternating the crops grown in a field from season to season, typically over a period of several years. The aim of crop rotation is to improve soil fertility, reduce pest and disease pressure, and promote the long-term sustainability of the agricultural system.

    Crop rotation works by alternating crops that have different nutrient requirements, rooting depths, and disease and pest susceptibility.

Principles: 

• It should be tailored to the present soil, climatic and financial factors.
• The series of cropping tailored for any particular place ought to be primarily based totally on the right land utilization. It ought to be so organized with regards to the fields at the farm that the yields may be maintained and soil losses thru erosion decreased to the minimum.
• The rotation ought to include enough acreage of soil-enhancing plants to hold and additionally build up the content material of the soil.
• In regions wherein legumes may be efficiently grown, the rotation ought to offer enough acreage of legumes to hold the nitrogen delivery of the soil.
• The rotation ought to offer roughage and pasturage for the livestock, saved on the farm.
• It ought to be so organized as to assist withinside the management of weeds, plant ailments, and insect pests.
• It ought to be supplied for the acreage of the maximum worthwhile coin plants tailored to the place.
• The rotation ought to be organized to make for the financial system in production. More exhaustive plants ought to be accompanied via way of means of much less exhaustive plants, e.g., potato, sugarcane, maize, etc. want extra inputs than oilseeds and pulses.
• The plants with faucet roots ought to be accompanied via way of means by the ones that have fibrous root systems.
•  Selection of crop ought to be hassle primarily based totally.

Advantages: 

• There is a usual boom withinside the yield of plants because of renovation of the right bodily situation of the soil Inclusion of plants having specific feeding zones and specific nutrient requirements assists in keeping a higher stability of vitamins withinside the soil.
• Diversification of crops reduces the danger of economic loss from destructive climate situations and harm to insects and pests.
• It allows extra even distribution of labor.
• There is an everyday float of profits over the year.
• The occurrence of weeds, pests, and illnesses is decreased and may be stored below control.
• Proper preference of plants in rotation assists to save you from soil erosion.
• It materials numerous desires of farmers and their cattle.
• Agricultural operations may be performed well-timed for all of the plants due to much less competition.

5. Agro meteorology:

 Agrometeorology is an interdisciplinary field that combines the principles of meteorology and agronomy to improve agricultural production and management. It involves the study of how weather and climate conditions affect crops, livestock, and other agricultural systems, and how these systems in turn can influence the local and regional climate.

Agrometeorology uses weather and climate data to provide farmers and agricultural managers with information that can help them make decisions related to planting, harvesting, irrigation, pest and disease management, and other aspects of crop and livestock production. This includes the use of weather forecasts, climate models, and remote sensing technologies to monitor soil moisture, crop health, and other factors that affect agricultural productivity.

6. Soils and tillage: 

    Soil is the foundation of agricultural systems and is one of the most critical components for crop production. It provides plants with the necessary nutrients, water, and physical support to grow and thrive. Agronomists study soil in order to understand its composition, structure, and properties, as well as how it interacts with plants and other organisms in the environment. They also study soil in order to develop sustainable land management practices that can help improve soil health and fertility and reduce soil erosion and other negative impacts.

    Tillage is the practice of mechanically working the soil, typically through plowing or cultivation, in order to prepare it for planting or to control weeds and other pests. Tillage can be both beneficial and harmful to soil, depending on how it is done and how often it is used. Over-tillage can lead to soil compaction, erosion, and loss of organic matter, while reduced tillage or no-till systems can help promote soil health and improve soil structure and fertility.

Objectives: 

• Provide and keep the best situations withinside the root zone (most viable intensity for crop roots) so that it will permit them to develop and feature successfully and without drawback in taking pictures of plant vitamins and water.
• Ensure that water enters the soil so that plant life has enough water to specific their ability boom and extra water passes via soil to groundwater and circulate flow, now no longer over the floor as runoff in which it could purpose erosion. There is more ability for expanded cropping performance as extra water is held withinside the soil profile than below traditional structures.
• Increase useful organic pastime withinside the soil so that it will keep and rebuild soil structure for superior water access and distribution withinside the soil profile competes with the ability of soil pathogens, make contributions to the decomposition of natural substances to soil natural depend and diverse grades of humus and make contributions to the capture, retention and sluggish launch of plant vitamins keep away from bodily or chemical harm to roots and soil organisms that could disrupt their powerful functioning.

Characteristics:

• Tillage changed into used to melt the soil and put together a seed mattress that allowed the seed to be positioned without difficulty at an appropriate intensity into wet soil with the use of seed drills or guide gadgets. This consequences in appropriate uniform seed germination.
• Wherever vegetation develops, weeds additionally develop and compete for light, water, and vitamins. Every gram of useful resource utilized by the weed is one much less gram for the crop. By tilling their fields, farmers have been capable of shifting the gain from the weed to the crop and permitting the crop to develop without opposition early in its boom cycle with ensuing better yield.
• Tillage helped launch soil vitamins wanted for crop boom via mineralization and oxidation after publicity of soil naturally depends on air.
• Previous crop residues have been integrated alongside any soil amendments (fertilizers, natural or inorganic) into the soil. Crop residues specifically unfastened residues, create troubles for seeding gadgets with the aid of using raking and clogging.

7. Dryland agriculture: 

    Dryland agriculture is a type of farming that is practiced in areas with limited rainfall or where water resources are scarce. It is typically found in arid or semi-arid regions and is often characterized by low precipitation, high evaporation rates, and high temperatures.

    In dryland agriculture, farmers rely on various techniques to conserve water and make the most of available resources. These might include practices such as crop rotation, conservation tillage, and the use of drought-resistant crop varieties.

Importance of Agronomy:

    Agronomy is an important field of study because it provides the scientific foundation for sustainable agriculture and the production of food, fiber, and other plant-based products. Here are some of the key reasons why agronomy is important:

Food security: Agronomy plays a crucial role in ensuring that enough food is produced to feed the world's population. By studying the interactions between plants, soils, climate, and other factors, agronomists are able to develop techniques and technologies that optimize crop production and reduce the risk of crop failure.

Environmental sustainability: Agronomy also helps to promote sustainable agricultural practices that minimize negative impacts on the environment. This might include practices such as conservation tillage, crop rotation, and precision agriculture that help to reduce soil erosion, minimize the use of chemical fertilizers and pesticides, and conserve water resources.

Economic development: Agriculture is a key driver of economic development in many countries, and agronomy plays an important role in helping farmers to increase their productivity and profitability. By studying crop growth and development, soil health, and other factors that influence agricultural productivity, agronomists are able to develop new technologies and practices that can help farmers to improve their yields and increase their income.

Climate change adaptation: Climate change is expected to have a significant impact on agricultural systems around the world, and an agronomy is an important tool for helping farmers to adapt to changing conditions. By studying the impacts of climate change on crops and soil, agronomists can help farmers to develop new techniques and technologies that can help to mitigate the negative effects of climate change on agricultural production.

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