What organism causes the type of die-back of a tree's branches known as canker?

Where on a plant would you expect to see the first signs of powdery mildew?

The curse of rose growers is rose Black Spot but do you know what type of organism it is caused by?

This is Botrytis cinerea. What is its usual name in the gardening world?

These roots are infected with the disease known as clubroot. Which group of plants are most often affected?

Between which two countries has animosity been created because of fireblight?

What is the name given to the group of fungi that create leaf disfiguration similar to that seen below?

Potato blight was responsible for the greatest farming tragedy in the history of the British Isles. How many people are estimated to have died during the Irish Potato Famine in the mid 1800s?

This attractive looking fungus is a deadly threat to gardeners. What is its name?

Pythium (as seen in the picture below) is one of a number of diseases that cause the sudden collapse of seedlings often referred to as 'damping off'. Which of the diseases below is NOT a cause of damping off?