Organic Farming: Pest and Disease Management

Pest and Disease Management in Organic Agriculture

• Healthy plants are more resistant to pests and diseases.
• The goal of organic farming is to foster healthy plant growth.
• Plant health depends on light, temperature, water, balanced nutrition, and optimal pH levels.
• Stress from unsuitable conditions weakens plants, making them vulnerable.

Prevention Practices and Monitoring

• Select varieties adapted to the local environment, including temperature, nutrient availability, and vulnerability to common pests.
• Use pathogen and weed-free seeds and planting materials from trusted sources.
• Mixed cropping systems reduce host plants for feeding, limiting pest pressure.
• Crop rotation reduces soil-borne diseases and increases soil fertility.
• Green manuring and cover crops enhance soil biological activity and the presence of beneficial organisms.
• Moderate fertilization supports steady plant growth and reduces vulnerability to infection. Excessive use can lead to salt damage.
• Balanced potassium supply helps prevent fungal and bacterial infections.
• Organic matter increases beneficial microorganisms in the soil, suppressing pathogenic fungi.
• Organic matter also stabilizes soil structure, improving aeration and water infiltration, and strengthens plant defenses.
• Suitable soil cultivation facilitates decomposition and controls weeds that host pests and diseases.
• Effective water management prevents waterlogging, which stresses plants and encourages pathogen infections.
• Avoid watering foliage, as it spreads water-borne disease and fungal germination.
• Encourage natural enemies by providing habitats and avoiding harmful products.
• Optimum planting times avoid periods when plants are most vulnerable to pests or diseases.
• Maintaining adequate plant spacing reduces disease spread and promotes better aeration.
• Sanitation involves removing infected plant parts to prevent disease spread.
• Eliminate plant residues after harvesting.
• Regular monitoring of pests, diseases, and weeds is essential for effective management.

Typical Signs of Pest Attacks on Crop Plants

• Most crop pests are insects, mites, and nematodes.
• Mammals (elephants, monkeys) and birds can also damage crops in Africa.
• Pest damage can be species-specific.
• Leaves with holes indicate caterpillar or weevil damage.
• Curled leaves suggest aphids.
• Damaged or rotten fruits often mean fruit fly larvae.
• Withering plants might be caused by noctuid larvae.
• Holes in branches or trunks may indicate lignivorous insects.
• Mites are very small, turning leaves and fruits yellowish if present.
• Nematodes, also small, primarily attack roots, leading to yellowing, wilting, and plant death.

Typical Signs of Disease Attacks on Crop Plants

• Most crop diseases are caused by fungi, bacteria, or viruses.
• Fungi are responsible for about two-thirds of infectious plant diseases.
• Some bacteria cause rotting by breaking down cell walls.
• Some bacteria produce toxins that damage plant tissues and cause early plant death.
• Some bacteria create blockage to water flow via very sticky sugars, leading to rapid plant death.
• Some bacteria produce proteins mimicking plant hormones, resulting in tissue overgrowth and tumors.
• Viruses mainly cause systemic diseases, often leading to chlorosis a change in leaf color.
• Viruses can create mosaic patterns, that result to a general reduction in plant growth and vigor.
• Constant monitoring of pest and disease levels enables timely intervention to prevent significant damage.

Monitoring methods

• Inspect fields regularly along a zigzag or M-shaped route for comprehensive coverage. This method is easy to implement.
• Bait traps can capture fruit flies.
• Yellow sticky cards are effective for trapping aphids.
• Light traps are particularly useful where noctuids are a problem.

Curative Methods: Promoting and Managing Natural Enemies

• Natural enemies of pests include fungi, bacteria, viruses, and insect predators.
• Promote these biological solutions.
• Minimize natural pesticide use, as chemical pesticides are not permitted in organic farming.
• Allow some pests to live to serve as food for natural enemies.
• Use diverse cropping systems like mixed cropping.
• Incorporate host plants that provide food or shelter for beneficial insects.
• Hedges of indigenous shrubs attract predators with nectar and pollen.
• Flower strips attract predators with nectar, pollen, and alternative hosts.
• Companion plants attract enemies within a crop, acting as a service station for them.

Mechanical Control

• Mass-trapping pests is an effective additional control measure through basic, cheap materials.
• Examples: light traps, color traps, water traps, and yellow sticky traps.
• Fruit bagging is a protection method against fruit flies laying eggs, preventing mechanical injuries, and promoting reliable harvest estimates.
• Bagging can be done with melon, bitter gourd, mango, guava, star fruit, avocados, and bananas.
• Trapped moisture with plastic bags can cause diseases.
• Dried plant leaves are good alternatives to plastic.

Biological Control

• Biological control uses natural enemies to manage the pest populations.
• Two approaches for biological control: preventive release and release upon pest population increase.
• Preventive release introduces natural enemies before pests cause significant damage.
• Releasing natural enemies during pest outbreaks is common with bacteria because they can't persist without a pest.

Antagonistic Microbes

• Natural enemies that kill or suppress pests or diseases can consist of fungi or bacteria, often called antagonists, microbial insecticides or biopesticides.
• Bacillus thuringiensis (Bt) has been a microbial insecticide since the 1960s.
• Nuclear polyhedrosis viruses (NPV) effectively control caterpillar pest species.
• Some fungi occur naturally and kill insects like aphids during humid weather.
• Trichoderma sp. prevents soil-borne diseases like damping-off and root rots.

Natural pesticides

• Botanical pesticides that are extracted from plants are toxic to insects.
• Botanicals such as rotenone, nicotine, and pyrethrins have been used in agriculture.
• Botanicals are contact, respiratory, or stomach poisons targeting a range of insects, including beneficial ones.
• Botanical pesticides break down quickly and reduce harm on the ecosystem.
• Neem contains azadiractin, which deters and kills caterpillars and whiteflies.
• Pyrethrum in mountainous regions in the tropics paralyzes most insects.
• Chilli and capsicum peppers repel and kill insects.
• Garlic has antifeedant, insecticidal, and repellent properties effective against various insect life stages.
• Despite being natural, some botanicals like nicotine can be dangerous to humans and natural enemies.
• Pyrethrins are not poisonous to humans, but they cause allergic reactions.

Other Practices for Disease Control

• Plant ashes from fireplaces are effective against ants, stem borers, termites, and potato moths.
• Sulfur controls disease in dust or liquid form, the odour discourages extensive use.
• Bordeaux mixture (copper sulphate and lime) is utilized on fruits, vegetables, and decorative plants for over 150 years.
• Acidic clays have fungicidal properties.
• Milk and baking soda can be used for disease control.

Nutrient Management in Organic Agriculture

• Soil fertility is key to agricultural productivity.
• Farmers should maintain soil fertility by replacing nutrients removed by crops.
• Replace nutrients with green manures, animal manures, and natural fertilizers.
• Monitor plant nutrients using a soil testing program.
• Soils deficient in nutrients cannot support crop production.
• Optimal soil includes loose structure with many cavities, visible organic matter, good aeration, and good water infiltration. It features many beneficial soil organisms.

Practices to Enhance Soil Fertility

• Compost and vermicompost.
• Green manures.
• Animal manure.
• Microbial fertilizers.
• Mineral fertilizers.

Composting

• Composting transforms organic materials into humus.
• Compost occurs faster, reaches higher temperatures, and results in a higher quality product compared to decomposition.
• The composting process has three phases: heating, cooling, and maturing.

The Heating Phase

• Compost temperatures rise to 60-70°C.
• Bacteria decompose the compost, while warmth destroys weed and pest seeds.
• Bacteria population increases due to oxygen levels.
• Humidity is essential for bacteria function.
• Heat increases and acidity decreases.

Cooling Phase

• Compost temperature will decline to 25 - 45°C.
• During the cooling phase, temperature declines to 25-45°C gradually as readily digested bacteria decreases.
• Fungi settle and decomposes the materials as the process is slow and temperature doesn't rise.
• Acidity increases as humidity declines.

Maturing Phase

• Mineralization, humic and antibiotic acids build up.
• Worms and soil orgasms inhabit heap.
• Compost has lost half its volume and is ready to use.
• The composts quality as fertilizers decreases over time.
• Compost needs less water than the heating phase.

Compost System Types

• Continuously fed systems do not heat up and are useful for continuous waste, but lack full advantages of heating.
• Batch-fed systems lead to hot composting, reduce nutrient loss, and result in superior quality compost.
• Vermicomposting uses earthworms to speed up composting and enhance it with nutrients and enzymes.

Green Manures

• Green manures are plants grown to add nutrients for the main crop.
• It can penetrate soil, suppress weeds, fix nitrogen, and provide food.
• Green manures release all nutrient types and encourages soil organisms to improve soil and water holding.

Factors to Consider Before Growing Green Manures

• Labor for tillage and sowing required.
• Green manures compete with main crops for nutrients, water, and light.
• Nitrogen is temporarily immobilized when coarse plant material is incorporated.
• Food crops are more appropriate if food and space is low.
• The benefits and uses of green manures occur over time.

How to Use Green Manures

• Choose right time for green manure crop rotation.
• Green manures need water for the seed germination process.
• Seed density has to be tested.
• Additional fertilization shouldn't be used, but inoculation of seeds with rhizobia may improve first-time nitrogen fixation.
• Digging in a green manure and planting next crop should not exceed 2-3 weeks to avoid nutrient losses.
• Plants should be crushed to allow easy decomposition if they have hard parts.
• Plants should only be worked to the surface soil to not be ploughed and should be limited up to 10-20cm.
• Material can be left surface as a mulch layer.

How to Choose Species of Green Manure

• Select appropriate species that fit into crop rotation and don't risk diseases.
• The important species should be adapted to rainfall and soil.

Animal Manure

• Farmyard manure includes animal waste and bedding material.
• It contains large amounts of nutrients.
• Nitrogen is released as waste decomposes.
• Chicken manure is filled with phosphorus.
• Organic manures contribute to building up organic matter into to improve soil.

How to Store Farmyard Manure

• Farmyard manure should be collected to a high quality.
• Stored manure is achieved by composting.
• Stored manure should be under anaerobic conditions.
• Liquid manure can be mixed with dry planting material to absorb water.
• Located next to a table will have to be protected or covered.
• Storing manure in dry areas should be under 90cm.

Monitoring of Manure

• White fungus indicate dry manure if white fungus appears (threads and white spots).
• Check for green colour indicates if manure is wet.
• Check if the manure is brown to black indicated by conditions.
• It is used with sugar or materials.

Microbial Fertilizers

• Consist of organic material, sugar, or starch and microorganisms.
• Test small scale for untreated pot because their in living form.
• Microbes help solubilize phosphorus.

Mineral fertilizer

• Mineral fertilizers use ground natural rock.
• May only be used to supplement to organic manures
• They can disturb soil life and result in unbalanced plant nutrition.

Organic Farming

• An integrated farming system that tries to enhance soil fertility and biological diversity.
• Organic farming reduces chemicals.
• New farming that repairs, maintains, and improves balance.

History of Bio-Farming

• Ancient Egyptians agriculture connects deeply for the cycle of the nile, an essential part of Egyptian farming and their environment.
• The annual flooding maintains soil fertility.

Inundation and Soil Fertility

• The yearly flooding brings water from Ethiopia and transfers it into farmlands.
• These nutrients are nitrogen and potassium that supports crop growth.
• Used nilometers to monitor floor levels.
• Ensured balance, deposition to prevent excessive farming.

Irrigation Systems

• Developed systems such as canals, basins, and shadufs to maximize the benefits of flood.
• System controls distribution and cultivation.

Crop Diversity

• Variety of crops containing wheat, barley, flax for linen, garlic, lettuce, dates, fig, grapes, legumes.
• Diverse crops maintained soil health.

Manure and Plant Residue

• Animal waste fertilized the soil.
• Crop residues were lift in field and turn to fertilizer for the soil.

Meaning and Importance of Organic Farming

• A farming system that uses organic matter.
• To conserve the eco system and reduce fertility of soil.

Benefits of Organic Farming

• Used because of its organic inputs.
• Is good for the environment.
• Generates more income.
• Helps health and provides food.

Limitations of Organic Farming

• Has a higher price and lacks awareness.
• Provides shorter shelf life.

The Green Revolution

• Refers to high-yield techniques of fertilizers in developed countries.
• Caused an increase of synthetic nitrogen.
• The UN have predicted there will e climate change in south and sub-Saharan Africa.

Bio Farming

• A farming system based on fertility of soil.
• Wastes from fertilizer.

Green Manuring

• A type of organic fertilizer from plant parts.

Crop Residues

• Materials lift in cultivation areas.

Biological Control

• The use of living organisms to control pests and disease.

Lady Bug and Crop Rotation

• Crop rotation helps improve rotation and soil health.
• The organisms improve plants and soil health.

Bio-Farming Future Prospects

• Includes a rise in demand for organic product up to 2021.

Climate Change

• Sustainable practices in biological tests, helps reduced soil health.

Future Prospects

• Protection of ecosystems.
• Conservation of ecosystems.
• Helps balance the food process.

Organic practices at Dina Farms

• Known by the integrated approach to agriculture.
• The farming helps control pest and conserve.

Weed management

• Weeds have capacity and alter the environment of crop.
• Practices try to keep weed population at level to harm crops and quality.

Characteristics of Weeds

• Enourmous amounts of seeds and maintain moisture.
• The use of tools and mulching helps keep plants from damaging the growth.
• The weeds don't grow from high altitudes or temperature.

Biological control

• Uses the fungus Fusarium oxysporum to reduce weed.

Mechanical control

• Measures used to prevent weeds from damaging crops.

Pasturing

• Sheep and goats tend to graze more during agriculture.