L is for ladybird

This is not a post about the First Lady of the U.S. from 1963-1969, a track on a Tears for Fears album, or the 1992 Rodney Dangerfield soccer comedy. Instead, it is about an insect pest new to North American viticulture.

Of the Coccinellidae family, the particular culprit is the Harmonia axyridis, or Asian Lady Beetle. She also goes by Japanese ladybug, Harlequin ladybird and Halloween ladybird (she might try to settle in your home as the weather chills in October).

I always thought these beetles were considered a good sign in the vineyard, as they have voracious appetites for aphids, which tend to suck juices from plants.  

Turns out ladybirds were first observed causing problems in the northeast US during the 2001 vintage.  They like to feed on sugar from damaged grapes late in the ripening process and they are often harvested along with the fruit.  When these little buggers get disturbed (which is quite likely during the crushing process), they emit a yellow-orange body fluid, which taints the wine. 

The goo is released from their legs and is called hemolymph and it contains a high concentration of isopropyl methoxy pyrazine.  Those of you more familiar with winespeak will recognize that this is the stuff which lends green flavors to wine – think Sauvignon Blanc.  Unfortunately, it also imparts a musty, nutty aroma and an astringent peanut-chocolate character to the wine. 

The shocking part of all this is that one adult beetle per 1.7 kg (3.75 lbs) of grapes is enough to cause noticeable funk in the wine!

We introduced the species to our country to control the soya bean aphid, and the ladies can now be found along the eastern seaboard, across central states and in Washington and Oregon.  Over a million liters of wine from Ontario have been dumped, as a solution (other than careful sorting) remains to be found.  Taint has also been reported in Italy, Germany, Holland, Belgium and the UK.

Not very lady-like, if you ask me.

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