Celest Byers, age 13, of Brownsville, Tex., for her question:

WHAT CAUSES PLANT ROT?

Rot is a plant disease in which the plant rots, or decays, because of fungi or bacteria that may infect the plant and kill the cells. The disease is caused by a fungus which destroys the fruit, twigs and  limbs.

There are many varieties of this disease. A few common varieties are bitter rot, potato rot, brown rot, black rot and dry rot.

Bitter rot is found mostly in apples, although it may also attack quinces and pears.

Potato rot is a dangerous disease because it can destroy an entire crop and cause a potato famine.

Brown rot destroys peaches and other stone fruits such as the cherry and plum. Small brown spots are found on the fruit. These grow until the entire fruit is infected. Black rot attacks sweet potatoes, grapes, pears and quince.

Dry rot is a disease that is common to timber. The disease also attacks some fruits and vegetables.

Rot is dangerous to plant life because it can quickly spread. It is difficult to control.