Blossom End Rot
Symptoms: A serious disorder of tomato, pepper, cucumber and eggplant, blossom end rot is an environmental problem (not fungal) caused by insufficient levels of calcium during fruit formation. This common garden “disease” is often brought on by rapid growth from too much fertilizer, high salt levels, drought or uneven soil moisture.
Blossom end rot occurs on both green and ripe fruits and is identified by water-soaked areas that mature into sunken, brown, leathery spots on the blossom (bottom) end. In many cases, secondary pathogens, which appear as a black, fuzzy-like growth, attack the affected area and cause complete rotting of the fruit. Blossom end rot will not spread from plant to plant.
Control: Since blossom end rot is physiological in nature, organic fungicides will not work as a control measure. Choose resistant vegetable varieties whenever possible. Prevent problems by keeping soil evenly moist and by foliar spraying plants with a kelp or calcium solution. Adding high levels of calcium (bone meal, oyster shell and gypsum) to the soil at planting time usually prevents this common garden problem from occurring. Mulching plants will conserve moisture and provide a more uniform water supply.
Avoid using high nitrogen fertilizers, which accelerate vegetative growth and reduce the uptake of calcium by plants.