Plant Diseases

• Tobacco mosaic virus (TMV)


  A very widespread plant infection that affects a number of different plant species including tomatoes
• Rose black spot


  A fungal plant disease
• Causes of rose black spot

  1. Spread by water

  2. Spread by wind
• You will find plenty of questions on infectious plant diseases in the revision workbook
• We can diagnose diseases in plants by looking for insects such as aphids, discoloration spots on leaves, stunted growth, decay or rot growths, and malformed stems or leaves
• Identifying plant diseases


  1. Use a garden manual or website

  2. Take the infected plant to a lab to identify the pathogen

  3. Use testing kits containing monoclonal antibodies
• Plant ion deficiency diseases

  Plant diseases not caused by pathogens
• A lack of the nitrate ion causes stunted growth because nitrate is needed for protein synthesis and therefore growth
• A lack of the magnesium ion causes chlorosis because magnesium is required to make chlorophyll, causing the leaves to lose their green coloration