Plant disease

• How to tell if a plant is ill

  Spots / discoloured leaves

  Abnormal growth

  Stunted growth

  Areas of rot / decay

  Malformed stems / leaves
• How can we diagnose a plant with a disease?

  Referring to garden manual or website

  Using a test kit with monoclonal antibodies

  Sending the plant to a lab to run testd
• Chemical plant defence:

  Substances that are produced by the plant to kill microorganisms
• Physical plant defence:

  Barriers that prevent microorganism from entering the plant
• Examples of physical defences of a plant

  cell wall - is a physical barrier

  Waxy cuticle - prevents entry of pathogens and reduces water loss
• What are examples of chemical defences of plants?

  insecticides - naturally produced by plants to kill insects , eggs and larvae

  Insect repellent - repellent the insect vectors that carry disease
• Examples of insecticides: 


  nicotine

  Neem

  Pyrethrims
• Examples of insect repellents

  citronella

  Oils
• adaptations against herbivores

  poisions

  Thorns

  Hairy stems

  Dropping of curling when touched

  Mimicry