How to recognise it
Black, leathery, rounded, concave lesions on the base of the fruit, which might at first sight resemble a fungal infection.
What causes it
A lack of calcium available to the plant from the soil (cells deprived of calcium collapse and discolour). Since calcium has to be taken up by the plant with water, underwatering when the fruits are developing is a common cause of this problem.
Why it’s a problem
Affected fruit becomes unsightly and inedible.
Where you are likely to find it
In tomatoes and peppers, more predominantly in container grown plants (eg grow bags) in glasshouses, where nutrients and water are likely to be less readily available.
How to prevent it
Never let the soil around fruiting crops dry out; water regularly and mulch to assist with water retention in the soil.
Avoid very acid growing media.
Grow small fruited varieties, which are less likely to be affected.
How to get rid of it
It cannot be cured, affected fruit should be removed.
Is it good for anything?!