Integrated Management of Damping-Off Diseases
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What does the indicative succulent tissue between corn seedlings suggest?

  • The seedlings have overgrown.
  • The seedlings are thriving well.
  • The seedlings are competing for nutrients.
  • The seedlings are suffering from damping-off disease. (correct)

    • What factor is essential for effective decision-making regarding seed treatments?

  • The use of high-yielding crop varieties
  • Knowledge of site-specific soil and climate conditions (correct)
  • General knowledge of pest management
  • The type of crop grown

    • Which abiotic stress is characterized by hindering seedling emergence?

  • Nutrient deficiency
  • Soil crusting (correct)
  • Excessive watering
  • Humidity

    • What was the main finding from the experiment on pesticide-free agroecosystems conducted in 2014?

    <p>Emergence rates varied significantly across different sites.</p> Signup and view all the answers

    What is a common symptom of post-emergence damping-off?

    <p>Seedling decay and wilting</p> Signup and view all the answers

    What is one method to suppress soil-borne pathogens mentioned in the content?

    <p>Perform soil solarization</p> Signup and view all the answers

    Which range indicates relatively acidic soil pH for optimal plant growth?

    <p>4.5–6.0</p> Signup and view all the answers

    What results from the interaction of biotic and abiotic stresses?

    <p>Symptoms can be indistinguishable.</p> Signup and view all the answers

    Which of the following best represents a key criticism of current breeding approaches for crop varieties?

    <p>Emphasis on market-driven and profit-centric criteria.</p> Signup and view all the answers

    Which symptom may indicate phytotoxicity from chemical fungicides?

    <p>Chlorotic patches</p> Signup and view all the answers

    What has been insufficiently emphasized in the integration of plant resistance with other IPM tactics?

    <p>The quantification of plant resistance benefits.</p> Signup and view all the answers

    What should be avoided regarding planting dates?

    <p>Sowing too late</p> Signup and view all the answers

    Which crop was mentioned as having a 100% emergence rate at two specific sites in the study?

    <p>Soft wheat</p> Signup and view all the answers

    What might the presence of stem lesions at ground level indicate?

    <p>Potential soil-borne pathogen infections.</p> Signup and view all the answers

    How can nutrient availability in soil be improved according to the information provided?

    <p>Through well-balanced fertilization</p> Signup and view all the answers

    What is the term used to describe thin and tough seedling stems?

    <p>Wirestem</p> Signup and view all the answers

    What notable percentage of emergence rate was reported in the Auzeville site?

    <p>43%</p> Signup and view all the answers

    What is a consequence of over-sowing or excessive plant densities?

    <p>Increased competition among plants</p> Signup and view all the answers

    What is NOT a potential symptom of damping-off disease?

    <p>Increased seedling vigor</p> Signup and view all the answers

    What is one notable consequence of focusing primarily on high-yielding crop varieties?

    <p>Adoption of short rotations or monoculture practices.</p> Signup and view all the answers

    What is recommended to prevent waterlogging in the growing environment?

    <p>Moderate humidity maintenance</p> Signup and view all the answers

    What type of crop practices could be overlooked due to the focus on high-yielding varieties?

    <p>Minor crops with potential for IPM</p> Signup and view all the answers

    What technique can be used to improve soil drainage?

    <p>Composting organic matter</p> Signup and view all the answers

    What agricultural practice should be avoided to support healthy crop growth?

    <p>Over-application of water</p> Signup and view all the answers

    What benefit does adopting long rotation schemes provide?

    <p>Reduces pathogen populations</p> Signup and view all the answers

    Which type of cover crop is likely to increase populations of damping-off pathogens?

    <p>Certain leguminous cover crops</p> Signup and view all the answers

    What is the primary purpose of tillage in relation to soil pathogens?

    <p>To incorporate plant residues into the soil</p> Signup and view all the answers

    What is a major drawback of chemical fungicides mentioned?

    <p>They can cause phytotoxicity on crops</p> Signup and view all the answers

    What are biocontrol agents primarily developed to substitute?

    <p>Chemical pesticides</p> Signup and view all the answers

    What does the application of biocontrol agents generally emphasize?

    <p>Lower negative impacts on crops</p> Signup and view all the answers

    Which bacteria are mentioned as antagonistic biocontrol agents?

    <p>Pseudomonas spp. and Bacillus spp.</p> Signup and view all the answers

    Why is it important to select appropriate cover crop species?

    <p>To optimize organic matter production and minimize pathogen risks</p> Signup and view all the answers

    What is a primary concern that leads to the use of alternative tactics rather than conventional pesticides?

    <p>General concerns over conventional pesticides</p> Signup and view all the answers

    Which of the following fungi are commonly targeted by benomyl and thiophanate methyl?

    <p>Fusarium and Pythium spp.</p> Signup and view all the answers

    What key challenge is highlighted in the management of damping-off diseases?

    <p>Complex nature of the diseases</p> Signup and view all the answers

    What is often a necessary step alongside the use of biocontrol solutions for damping-off diseases?

    <p>Diagnosis of the involved pathogens</p> Signup and view all the answers

    Which chemical is noted as being active against Phytopthora and Pythium spp.?

    <p>Metalaxyl</p> Signup and view all the answers

    What limitation affects the chemical control of damping-off diseases?

    <p>Limited active ingredients due to cost</p> Signup and view all the answers

    What is one research priority essential for understanding damping-off diseases?

    <p>Correct identification of damping-off pathogens</p> Signup and view all the answers

    Which of the following is NOT mentioned as a commonly used fungicide for damping-off diseases?

    <p>Thiomethoxam</p> Signup and view all the answers

    What is the primary role of lytic enzymes produced by biocontrol organisms?

    <p>To degrade essential compounds for pathogen development</p> Signup and view all the answers

    Induced systemic resistance (ISR) differs from systemic acquired resistance (SAR) in that ISR is primarily focused on what aspect?

    <p>Stimulating the plant’s immune system</p> Signup and view all the answers

    Biocontrol organisms can release suppressive substances. What is the direct effect of these substances?

    <p>They inhibit the growth of soil-borne pathogens</p> Signup and view all the answers

    Culture-independent methods, such as next-generation sequencing, are advantageous because they allow for what?

    <p>Identification without prior cultivation</p> Signup and view all the answers

    The competition for nutrients among soil-borne pathogens can be affected by what characteristic of biocontrol organisms?

    <p>Their ability to effectively colonize plant environments</p> Signup and view all the answers

    What is a significant outcome of the actions of biocontrol organisms against pathogens?

    <p>Suppression of pathogen growth</p> Signup and view all the answers

    In the context of plant-pathogen interactions, what is one of the consequences of biocontrol agents producing metabolites?

    <p>Inhibition of essential pathogen activities</p> Signup and view all the answers

    What does the practice of visual inspection of symptoms in disease identification fail to provide?

    <p>Accurate microbial identification</p> Signup and view all the answers

    Study Notes

    Integrated Management of Damping-Off Diseases

    • Damping-off is a disease that affects germinating seeds and young seedlings.
    • It's a significant yield constraint in nurseries and fields for various crops.
    • Conventional fungicides are commonly used but lead to pesticide resistance and environmental concerns.
    • Knowledge gaps exist in pathogen biology, disease epidemiology, and non-chemical management strategies.
    • Damping-off is a global problem affecting various agricultural and forestry crops.
    • Numerous soil-borne fungi and fungus-like organisms cause damping-off, but only some frequently.
    • Losses from damping-off can range from 5% to 80% of seedlings, creating heavy economic losses.
    • Biocontrol solutions are being researched with potential future perspectives.
    • Integrated pest management (IPM) combining preventive and curative strategies is crucial.

    Symptoms of Damping-Off

    • Pre-emergence symptoms: Seed decay before emergence or stem death before emergence.
    • Post-emergence symptoms: Seedling decay, wilting, collapse, leaf spotting, or root rot after emergence.
    • Abiotic factors like excess moisture, temperature extremes, and soil crusting also contribute to symptoms.

    Integrated Management Strategies

    • Seed treatment: Using treatments to enhance germination and seedling vigor.
    • Host resistance/tolerance: Utilizing crop varieties resistant or tolerant to damping-off.
    • Best cropping practices: Implementing appropriate agricultural practices for managing pathogens.
    • Seedling treatment: Using effective products timely for infected seedlings includes conventional and biocontrol options.

    Key Challenges and Future Priorities

    • Precise pathogen identification: Including non-secondary colonizers and anastomosis groups.
    • Understanding pathogen interactions: With each other and other organisms.
    • Abiotic factors and their roles: In seed and seedling predisposition to damping-off.
    • Disease-suppressive seedbeds: With or without conservation agriculture.
    • Modeling disease dynamics.

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    Integrated Management of Damping-Off Diseases PDF

    Description

    This quiz covers the integrated management of damping-off diseases affecting seedlings and young crops. It highlights the importance of understanding pathogen biology, the limitations of conventional fungicides, and the exploration of biocontrol and IPM strategies. Test your knowledge on the symptoms and management of this significant agricultural challenge.

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