chlorosis, vine disorder in which parts or all of the foliage turn yellow due to lack of chlorophyll. The most common and extreme chlorosis is that which is visible in spring and early summer and is caused by iron deficiency, which is common on soils high in limestone. Lime-induced chlorosis became a problem in parts of France as a consequence of phylloxera invasion at the end of the 19th century, since american vine species sourced initially in the eastern US and used as phylloxera-resistant rootstocks were more prone to iron deficiency than were the original vinifera root systems. This problem, known in French as chlorose calcaire, has been largely overcome now by the selection of lime-tolerant rootstocks suitable for calcareous soils, such as 41 B or the newer Fercal. In Burgundy and Champagne, where soils tend to be high in limestone, it has been difficult to find rootstocks with sufficient lime tolerance for healthy vine growth. This sensitivity of early post-phylloxera rootstocks to lime-induced chlorosis may provide part of the explanation for an apparent drop in quality in post-phylloxera wines, according to some historical authorities.
