BOTRYTIS FRUIT ROT, commonly known as gray mold rot, is the major fruit rot attacking strawberries in southern California fields, ft is caused by the fungus, Botrytis cinerea, which thrives in wet conditions and cool temperatures. Botrytis spores are produced in tremendous quantities and are carried by the wind. The fungus usually attacks through senescent dead petals, stamens, or other delicate plant tissue. Much of the infection of the fruit originates at the stem end, but the fungus is able to penetrate the unbroken skin of the berry.