Botrytis cinerea Pers.:Fr., the causal agent of gray mold, inflicts serious food and ornamental crop losses, particularly after harvest (57). Disease control is difficult, because the pathogen can attack crops at any stage of growth and can infect all plant parts. B. cinerea is especially important as a postharvest pathogen, because environmental conditions and the susceptibility of the crop tend to favor its development. Many of the strategies currently used to control gray mold, particularly the use of fungicides, kill or inhibit growth of the pathogen. As the application of fungicides becomes more restricted and fungicide resistance in pathogen populations becomes more widespread, the identification and manipulation of host disease-resistance mechanisms will become increasingly important in minimizing losses.