FROM THE DICTIONARY:
 

BOTRYTIS: Also called noble rot, this beneficial mold develops on grapes under certain environmental conditions. However, under the wrong circumstances (such as unripe grapes), gray rot develops and spoils the grapes. When carefully cultivated, botrytis causes the grape to shrivel, concentrating and intensifying both sugar and flavor. In addition, the acid levels remain high, which prevents the resulting wines from being cloyingly sweet. Most winemakers are exhilarated when noble rot descends on their grapes because it gives them fruit from which to make very elegant, intensely flavored dessert wines. In California, botrytised wines are usually referred to as late harvest or select late harvest. In France, where noble rot is called pourriture noble, the best-known beneficiaries are the famous wines of sauternes. Noble rot is called Edelfäule in Germany, where winemakers are experts at producing a large variety of elegant wines such as trockenbeerenauslese and beerenauslese. The renowned Hungarian tokay Aszú is also a popular botrytis-infected wine. In Italy, botrytis cinerea is called muffa nobile. A wide range of grape varieties are subject to the positive effects of noble rot. These include chenin blanc, furmint, gewürztraminer, hárslevelü, optima, ortega, riesling, sauvignon blanc, scheurebe, and sémillon.