Farmers always get concerned when they notice a dry, sunken decay on the blossom end of their tomato crop. This is common on the first tomato crop grown after a dry period. The disorder is known as blossom-end rot.
The disorder first appears as water-soaked spots on the blossom-end, or bottom, of the tomato. The affected tissue breaks down rapidly and the area becomes sunken, dark brown or black, and leathery. This can happen at any time as the tomatoes mature, and most often on the first tomatoes of the season.