A gardener finds yellow patches on the leaves of a plant. Why can the gardener not be certain which pathogen is present?
The pathogen is destroyed by the plant before any sign appears
The same sign is produced by several pathogens and by ion deficiencies
Signs on the leaves develop too slowly to be matched to a pathogen
Yellow patches are a defence response rather than a sign of disease
58 exam-style questions on AQA GCSE Biology 3.3 Plant disease, covering 3.3.1 Detection and identification of plant diseases and 3.3.2 Plant defence responses. Each one has a worked solution and a mark scheme showing where the marks go.