Ladybug Taint

ladybug taint, also known as lady beetle or ladybird taint is an off-flavour found in both grape juice and wine that contributes undesirable peanut- and/or green-like aromas and flavours, and possibly excessive bitterness. Two lady beetle species that migrate to vineyards during autumn—the seven-spot ladybird/ladybug (Coccinella septempunctata) from Europe, and particularly the multicoloured Asian lady beetle (or harlequin ladybird, Harmonia axyridis)—are known to cause the taint in the US and Canada. Both were originally introduced to North America to control aphids. It is unlikely that the beetles directly harm the grapes. Instead, they cause contamination after they are inadvertently harvested with the fruit and are incorporated in the must. The compounds responsible are alkyl-methoxypyazines—components of the insects’ haemolymph—and are difficult to remove from affected juice and wine, although juice settling and must-heating prior to fermentation can help. While not always openly acknowledged, ladybug taint is a problem in some wines and vintages across many of the world’s wine regions, including the US, France, Germany, and Canada. The first major incidence in northern North America was in 2001, while the 2004 and 2011 vintages in Burgundy were probably the first two to be widely discussed in this context. In Europe, however, the culprit seems to be the common seven-spot ladybird.