Greenhouse Environmental Control Quiz
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Questions and Answers

What is the recommended treatment method and duration for using heat as an agent for disinfection?

  • Methyl bromide for 1-3 days
  • Chloropicrin for 24-48 hr
  • Formalin for 14-36 hr
  • Steam for 30 min at 180˚ F (correct)

    • How long should methyl bromide be allowed to aerate before use?

  • 1-3 days
  • 30 min
  • 24-28 hr (correct)
  • 14 days

    • What is the recommended application rate of chloropicrin (tear gas) for treatment?

  • 8.0 g/cu.ft. of medium
  • 3-5 ml/cu.ft. of medium (correct)
  • 10 ml/cu.ft. of medium
  • 20 ml/l of water

    • What should be done after applying basamid to the medium?

    <p>Cover for 7 days with gas proof cover</p> Signup and view all the answers

    What should be done to disinfect physical propagation facilities?

    <p>Use formalin mixed with water</p> Signup and view all the answers

    What is one potential disadvantage of untreated wooden benches?

    <p>They can rot and become infested with pests</p> Signup and view all the answers

    Which of the following is NOT a recommended method for disinfecting seeds before entering a greenhouse?

    <p>Aphid spray</p> Signup and view all the answers

    What is an important feature of benches used for pot plants in a greenhouse?

    <p>They should enable better light access</p> Signup and view all the answers

    Which light range is most desirable for supplemental photosynthetic lighting in greenhouses?

    <p>400 to 700 nm</p> Signup and view all the answers

    What effect does reducing far-red light and increasing blue light have on plants?

    <p>Plants exhibit shorter, darker colors and become stronger.</p> Signup and view all the answers

    Which of the following plants requires the highest optimal light level?

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

    What is the purpose of greenhouse glazings developed with additives or pigments?

    <p>To filter certain wavelengths of light.</p> Signup and view all the answers

    Which method is NOT commonly used to reduce light levels in greenhouses?

    <p>Installing blackout curtains</p> Signup and view all the answers

    What is the primary purpose of pinching the first flower after one month from planting a rose plant?

    <p>To initiate additional bud growth</p> Signup and view all the answers

    How does plant spacing affect light levels in a greenhouse?

    <p>Tighter spacing reduces light availability.</p> Signup and view all the answers

    Which light quantity range is required for crops like cucurbits and sweet potato?

    <p>32.2 to 86.1 klux</p> Signup and view all the answers

    How much water do rose plants require daily for optimal growth?

    <p>6 mm/day</p> Signup and view all the answers

    What does bending the mother shoot towards the path achieve in rose plant cultivation?

    <p>It initiates bottom break ground shoot.</p> Signup and view all the answers

    Which aspect of light quality is crucial for affecting phytochrome photoreceptors?

    <p>Proportion of far-red light</p> Signup and view all the answers

    Which of the following practices is performed after four and a half months from planting roses?

    <p>Cutting strong ground shoots</p> Signup and view all the answers

    What is a consequence of bending in rose plants?

    <p>Enhanced root system development</p> Signup and view all the answers

    Why is it important to manage weak shoots in rose plant cultivation?

    <p>They need to be removed to enhance overall plant structure.</p> Signup and view all the answers

    Which cultural practice is NOT recommended for rose plants?

    <p>Allowing immediate flowering after planting</p> Signup and view all the answers

    What is the significance of removing buds from a bended stem in rose cultivation?

    <p>To check the incidence of pests and diseases.</p> Signup and view all the answers

    What is the ideal flower yield of roses per square meter?

    <p>250-350 stems/m2</p> Signup and view all the answers

    What should be done immediately after cutting the stems of roses?

    <p>Put them in clean plastic buckets with a 500 ppm citric acid solution</p> Signup and view all the answers

    At which stage should roses be cut for optimal development?

    <p>When the buds are just opening with visible color</p> Signup and view all the answers

    What is important for preventing vascular blockage after harvesting roses?

    <p>Re-cutting stems in warm water with citric acid</p> Signup and view all the answers

    What is the benefit of using BAP before the flowering flush?

    <p>It improves flower yield</p> Signup and view all the answers

    What temperature range is ideal for storing roses in cold storage?

    <p>0 to 20 C</p> Signup and view all the answers

    How long can roses be kept in a preservative solution in cold storage without suffering longevity issues?

    <p>4-5 days</p> Signup and view all the answers

    What is the recommended pH level for the water used in hydrating roses?

    <p>pH 3.0 – 3.5</p> Signup and view all the answers

    What is the primary role of sucrose in floral preservative composition?

    <p>To provide energy for the flowers</p> Signup and view all the answers

    Which of the following pests is NOT listed as a principal pest of roses?

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

    What is the recommended volume of preventive spray for controlling pests and diseases?

    <p>1500 litres/spray</p> Signup and view all the answers

    Which of the following diseases is associated with roses?

    <p>Powdery mildew</p> Signup and view all the answers

    What is the optimal interval suggested for the preventive spray program?

    <p>Once in a week</p> Signup and view all the answers

    Which material is recommended for long-term transport of flower bunches?

    <p>Telescopic style boxes</p> Signup and view all the answers

    How are rose stems typically prepared for packing?

    <p>Evened up and tied in bunches</p> Signup and view all the answers

    How many stems can typically fit in a box meant for transporting roses?

    <p>400 to 1000 stems</p> Signup and view all the answers

    Study Notes

    Controlling CO2 in Greenhouses

    • A single sensor receives information from multiple sampling tubes and controls CO2 generators in each greenhouse

    Controlling Light in Greenhouses

    • Light Quality:
      • Broad light spectrum from 400 to 700 nm is desirable
      • Red light is important for photoreceptor
      • Reducing far-red and increasing blue light results in shorter, darker, and stronger plants
      • Greenhouse glazings can filter specific wavelengths to change light ratios
    • Light Quantity:
      • Different species have different optimal light levels
      • Plant spacing, nutrition, and age can affect light levels
      • Cucurbits, capsicum, brinjal, and sweet potato require 32.2 to 86.1 klux light levels
      • Cabbage and potato require 21.5 to 86.1 klux light levels
    • Recommended Light Levels (in moles/m2/sec):
      • African violet:  150 – 250
      • Foliage plants: 150 – 250
      • Carnation, Chrysanthemum, Geranium, Cucumber, Lettuce, and Strawberry: 250 – 450
      • Roses and Tomato: 450 – 750
    • Greenhouse Shading Methods:
      • Shading compounds on glazing
      • Retractable shade systems

    Greenhouse Sanitation

    • Disinfecting Facilities:
      • Propagation rooms, containers, flats, knives, working surfaces, benches, etc. can be disinfected using formalin or sodium hypochlorite solutions
      • Regular insecticide spraying addresses insects
      • Seed or planting materials should be disinfected before moving into the greenhouse
    • Greenhouse Entry:
      • Disinfectant solutions like trisodium phosphate or potassium permanganate at the entry helps eliminate pathogens from personnel

    Benching

    • Benches raise plants off the greenhouse floor, preventing diseases and improving light conditions
    • Tiered benches optimize space utilization
    • Benches can be made of metal, wood, or plastic
    • Wooden benches require preservative treatments to prevent rot and pests

    Irrigation and Drainage in Rose Cultivation

    • Rose plants require a lot of water, at least 6 mm/day (about 60 cum/ha/day)
    • Drainage lines below beds are essential for excess water disposal

    Cultural Practices for Rose Cultivation

    • Initial Plant Development:
      • Pinch first flower to promote branching growth
      • Bend the mother shoot towards the path to initiate bottom break ground shoot
    • Plant Structure Development:
      • Bend weak ground shoots at ground level
      • Cut strong ground shoots after four and a half months from plantation
    • Bending:
      • Maximizes leaf area for strong root system
      • Removes suckers and buds to control pests and diseases
      • Breaks apical dominance
    • Support System:
      • Provides stability and makes intercultural operations easier
    • Pruning:
      • Stems are cut back to 4-5 nodes, removing weak shoots
      • Phased pruning ensures flowering from September to March

    Rose Harvesting, Post-Harvest Management, and Pests/Diseases

    • Harvesting:
      • Roses should be cut at the right stage, when buds are opening and color is visible
      • Cut stems are immediately placed in citric acid solution or chrysal – RVB
      • Ideal flower yield is 250-350 stems/m2
    • Hydration:
      • Recut stems and place them in warm water with citric acid to prevent vascular blockage
    • Preservatives:
      • Preservatives with citric acid, HQC/captan, sucrose, STS, and cytokinin are used to extend longevity
    • Packing:
      • Roses are bunched, wrapped, and packed in boxes
      • Boxes can contain one variety, one grade, or mixed colors
    • Pests:
      • Red spider mite
      • Leaf rollers
      • White fly
      • Thrips
      • Aphids
      • Nematode
    • Diseases:
      • Powdery mildew
      • Downy mildew
      • Botrytis
      • Pruning die back
      • Black leaf spot
    • Control:
      • Preventive spray program with Dithane M-45, Metasystox, and Karathane

    Perpetual Carnation – Dianthus caryophyllus

    • Important cut flower due to its long vase life, diverse colors, and forms
    • Two main types: Standard and Spray carnations

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    Description

    Test your knowledge on controlling CO2 and light in greenhouses. This quiz covers various aspects including light quality, light quantity, and optimal levels for different plant species. Understand how these factors influence plant growth and development in greenhouse settings.

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