plant diseases

• What is a pathogen?

  A pathogen is an organism that causes a disease.
• What are the four main types of pathogens?

  • Virus
  • Bacteria
  • Fungi
  • Protists
• What is the life cycle of a pathogen?

  Pathogens infect a host, reproduce, spread, and then infect other organisms.
• What are diseases caused by pathogens called?

  Communicable diseases.
• What does the term transmission refer to in the context of diseases?

  Transmission refers to the spread of communicable diseases.
• How do plant pathogens affect biodiversity?

  They kill or reduce the growth of many plants, which can reduce biodiversity.
• What historical event is associated with plant pathogens and starvation?

  The Irish potato famine around 1850.
• What pathogen caused the blight during the Irish potato famine?

  A fungus caused the blight.
• What is the tobacco mosaic virus known to infect?

  Tobacco and closely related species like tomatoes and peppers.
• How is the tobacco mosaic virus transmitted?

  By contact between plants, either naturally or on the hands of farmers.
• What part of the plant does the tobacco mosaic virus infect?

  It infects the chloroplasts of plant leaves.
• What effect does the tobacco mosaic virus have on leaves?

  It changes their color from green to yellow or white in a mosaic pattern.
• How does the tobacco mosaic virus affect photosynthesis?

  It reduces the plant's ability to photosynthesize and grow properly.
• What is the only option for farmers dealing with the tobacco mosaic virus?

  To stop their crops from being infected or reduce the spread.
• What disease is caused by the rose black spot fungus?

  Rose black spot.
• What symptoms does the rose black spot fungus cause on leaves?

  It causes black or purple spots on the leaves, which may turn yellow and drop off.
• How is rose black spot transmitted?

  It can be transmitted in air or water as well as by direct contact.
• What can be used to treat rose black spot?

  Fungicides and by removing and destroying infected leaves.
• What are aphids?

  Aphids are insects that infest plants.
• What effect do aphids have on plants?

  They suck sap from new shoots, reducing the growth rate and can eventually kill the plants.
• How do gardeners control aphid populations?

  By cultivating ladybirds, which eat aphids.
• What are deficiency diseases?

  Diseases caused by a lack of essential vitamins or mineral ions.
• What is an example of a deficiency disease in humans?

  Scurvy, caused by a lack of Vitamin C.
• How do plants suffer from deficiency diseases?

  When they do not have enough mineral ions.
• What do plants use nitrates for?

  As a supply of nitrogen needed to make proteins for healthy growth.
• How do plants absorb nitrates?

  Through their roots in water.
• What happens to leaves without sufficient nitrates?

  The amount of chlorophyll reduces, turning leaves pale green or yellow.
• How does nitrate deficiency affect photosynthesis?

  It reduces the plant's ability to photosynthesize and grow properly.
• What can farmers do to increase nitrate levels in plants?

  Add chemical or natural fertilizers, such as manure.
• What do plants use magnesium ions for?

  To make chlorophyll in their leaves.
• What is the effect of magnesium ion deficiency on plants?

  It limits photosynthetic ability and compromises plant growth.
• How can deficiency diseases in plants be investigated scientifically?

  • Measure the growth of barley seedlings.
  • Sow seeds on cotton wool in Petri dishes.
  • Add different nutrient solutions.
  • Record the total dry mass of seedlings after two weeks.
• What are the symptoms of plant diseases caused by pathogens?

  They can cause a range of symptoms that help identify the pathogen.
• What are some common symptoms of plant infections?

  • Stunted growth
  • Spots on leaves
  • Decay
  • Malformed stems or leaves
  • Discoloration
  • Presence of pests
• How do farmers and gardeners identify plant diseases?

  By using books, the internet, or consulting local garden centers.
• What is one method scientists use to identify difficult plant diseases?

  Analyzing cuttings of the plant using testing kits containing monoclonal antibodies.
• What are the physical defenses plants have against pathogens?

  • Thick bark as a physical barrier
  • Cellulose cell walls
  • Waxy cuticle on leaves
• What are the chemical defenses plants have against pathogens?

  • Antibacterial chemicals produced by some plants
  • Poisons developed by plants like stinging nettles
• What is one way farmers can enhance plant resistance to infections?

  By genetically engineering crop plants.
• What are some mechanical plant defenses against herbivores?

  • Thorns and hairs on plants
  • Drooping leaves in response to touch
  • Mimicry to avoid being eaten