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7.3 perform an investigation to examine plant shoots and leaves and gather first-hand information of evidence of pathogens and insect pests
perform an investigation to examine plant shoots and leaves and gather first hand information of evidence of pathogens and insect pests
- To perform this investigation, you may need some background information to aid identification of the pathogens. Use gardening books or the Internet to gather pictures of plant diseases, such as the following:
- Plant diseases
Iowa State University Entomology Department, USA provides you with a lot of photos of plants that have been attacked by different diseases and pests.
- Damping off
of seedlings, Ohio State University, USA
This is caused by a fungus. Read the information about the fungal disease and then read about an Australian example.
- Attacks by aphids
, scale insects and other insects. University of Kentucky, USA Although this is an American website, aphids are found in Australia too, so this site will provide you with useful information. Plants that are commonly infested with aphids are roses. If you or your neighbours have roses, look on the underside of the leaves to see if there is any sign of aphids.
- When you know what several plant diseases look like, go to an area of vegetation (such as a garden, park or area of bush) and examine plant shoots and leaves to gather evidence of plant diseases caused by pathogens or insect pest attack. You should aim to identify at least two examples of pathogens and insect pests if possible. Look for black patches on the leaves, white powdery residue or other spots that indicate a pathogen such as a fungus, or holes in the leaves caused by insect pests such as catepillars. Use a hand lens to observe the symptoms.
- For each example, record observations systematically and use the evidence to suggest what kind of organism has caused the disease.