California: Stink Bug Closes In on Wine Country

May 12, 2015

(Wines&Vines) - Sometimes it seems as though a new insect pest is announced every month. The brown marmorated stink bug (also known as BMSB or Halyomorpha halys), which already has become a threat to winemaking in the fast-emerging mid-Atlantic states, has established itself in parts of California and seems sure to pop up in Napa and Sonoma counties soon.

Chuck Ingels, farm advisor for the University of California Cooperative Extension in Sacramento County, which is infested with the bugs, discussed BMSB at a recent Napa Valley Grapegrowers’ Sustainable Viticultural Practices Seminar.

The BMSB can impact wine in a number of ways. First, it can damage grapes by piercing and feeding on the fruit, which can lead to increased susceptibility to bunch rots.

The distinctive odor excreted by the bug as a defense is trans-2-decenal and trans-2-octenal. It smells like fresh cilantro but to some observers, is “skunky,” “citrusy” or “piney.” It is apparent in fresh must, but different studies have disagreed on its impact in finished wines.

A study by Joe Fiola at the University of Maryland in 2010 found perceptible aroma in juice at levels of 5-10 bugs per lug, but no distinguishable taint in the juice after four months.

With 10-20 BMSB per lug, there was perceptible aroma during red fermentation but again no distinguishable aroma in the wine following fermentation and racking.

At Oregon State University (Tomasino et al., 2013 ASEV abstracts), they tested one bug per four clusters of Pinot Noir, one bug per two clusters and no bugs. They detected distinct aroma during destemming and pressing with bugs present, and the resulting wines contained more trans-2-decenal than the control. The infected wines were perceived as different from the control.

Elizabeth Tomasino of the Department of Food Science and Technology at Oregon State University also has conducted BMSB research that will be published soon.

The bugs are also nuisances, as they gather in flocks in tasting rooms and wineries.

Where they’re found

The native of China, Japan, Korea and Taiwan in East Asia is a crop pest in its native range and now in the United States. 


Share: Delicious Digg StumbleUpon Reddit Furl Facebook Google Yahoo Twitter

Comments:

 
Leave a comment





Advertisement