Look on the tag for initials V. F. N. or T. to indicate resistance to these diseases. There are two kinds of tomatoes, determinate and indeterminate.
Determinate tomatoes stop growing and flowering when they reach a certain height.
People in short season areas like to plant these kinds of tomatoes because they produce lots of fruit in a short period of time. They tend to take up less space than the indeterminate varieties. Indeterminate tomatoes continue to grow and fruit all season until kill them. These generally require staking or a cage. The best tomatoes are the ones you start from seed.