Blossom End Rot is characterized by a dry, leathery scar on the bottom, or blossom end of the fruit. This, too, may be caused by uneven soil moisture, especially during hot, dry periods, and, again, mulching along with careful watering may help. Blossom End Rot is caused also by a calcium deficiency in the soil. Catfacing is a puckering at the blossom end and may be caused by cool, cloudy weather during the blooming phase which causes the blossom to stick to the developing fruit. This scar sometimes goes deep inside the fruit, and there isn't much we can do to prevent it.
Insects are always a challenge.
If you see a hornworm with white spikes, he has already met his doom, and has become a host to a beneficial wasp. However, he can still consume tomato leaves at a rapid rate as long as he lives. The Fruitworm , which eats holes in the fruit and buds, usually requires a spray for control. The fruitworm is identical to the corn earworm, so corn and tomatoes should not be planted next to each other. Suspect these tiny, black jumping bugs if you see many tiny holes in the leaves of your tomato plants.