Many people in North America have already met the multicolored Asian lady beetle. It looks like an ordinary ladybug, but it has some bad habits. It stinks, it bites and it invades homes when the winter approaches and stays there until spring. And not only is it a pest in our houses, it has decided that it likes wine too. The Great Lakes Radio Consortium’s Victoria Fenner has the story:
Many people in North America have already met the multicolored Asian lady beetle. It
looks like an ordinary ladybug, but it has some bad habits. It stinks, it bites and it
invades homes when the winter approaches and stays there until spring. And not only is
it a pest in our houses, it has decided that it likes wine too. The Great Lakes Radio
Consortium’s Victoria Fenner has the story:
Ann Sperling goes out to the vineyards every day to check for bugs. She’s the vintner
with Malivoire Winery. Malivoire is a small organic winery in the Niagara Peninsula in
Southern Ontario, just north of the New York State border. There’s one kind of bug in
particular that Ann is hoping she doesn’t see – the multicolored Asian lady beetle.
It was introduced to North American in 1916 to control help aphids on plants. In 1988 in
Louisiana, the ladybug population suddenly started to grow. Scientists still don’t know
what happened to make them reproduce so fast at that time. But in only six years, it
spread as far as the northern states and southern Canada.
The spread of the bug has been very bad for the grape and wine industry. Sperling is
nervous about these ladybugs because she was caught by surprise a few years back. She
didn’t know anything about the problems they would cause to her wine at the time.
“Typically there is a certain number of insects including wasps and things like that that
are harvested with the fruit and it doesn’t cause any problems in the processing. And in
2001 there were these Asian lady beetles and they infected, or affected, the flavor of the
wine, so that there were many wines from that vintage throughout the Niagara peninsula
that had the characteristic flavor and were not saleable.”
The big problem is that Asian ladybugs are the skunks of the insect world. Just like
skunks, they give off a bad smell to discourage predators. And they release a sticky
brown substance from the joints in their body when they’re stressed and they make a real
At harvest time, there’s a lot of commotion in the vineyards. That’s when the bugs get
really upset, and they leak all over the grapes. They also hang on to the grape clusters
and are pressed into the wine along with the fruit. Sperling says they had to dump half of
their 2001 vintage because it had a bitter taste and a bouquet of raw peanuts.
Because of this, the multicolored Asian Ladybug has become a big problem for wineries
in the Great Lakes region and in the Midwest. It’s such a pressing problem for the wine
industry that the Ontario Grape Growers Association has set up a special task force to
figure out what to do. Gerry Walker is heading up the task force. He says the ladybug
isn’t a problem this time of year, but the populations are being monitored to head off
potential problems during the harvest season.
“First of all, the bug usually is outside the vineyard for most of the season. It’s usually
located in soybean fields or forested areas. It has a wide host range in terms of what
aphid species it will feed on. It primarily feeds on aphids during the growing season,
populations build up and at the end of the growing season when cool temperatures occur
it cues the bug to look for hibernating wintering sites and also to fill up on sugars in order
to hibernate. And so they move to the vineyards as the grapes begin to ripen.”
Asian ladybugs are found across most of the southern part of North America –
everywhere that there is an aphid population.
And there is a connection between soybean fields and vineyards. Here’s why – aphids
like to eat soybeans, and the multicolored Asian ladybeetle likes to eat aphids. When the
soybeans are harvested, the beetles look for new food and move to the vineyards.
Mark Sears is an environmental biologist at the University of Guelph. He’s beginning a
study to find out the movement patterns of the ladybug. He says we can’t get rid of them.
All we can do is control them.
“This beetle’s been here long enough that there’s no way we’re going to eliminate it. We
just want to suppress its numbers so that it isn’t a problem, in this case, in the vineyards.
If we do a good job of suppressing aphids – we’re not going to eliminate them either, but
if we keep them at lower numbers then there’s less food available for beetle populations,
there will be fewer of them to move to vineyards. And therefore we should be able to
contain the problem, not the insect itself.”
Ann Sperling is one of many winemakers who’s happy to see that this major study of the
ladybug is being done. But the invasion of 2001 was also a valuable learning experience.
Sperling says they’re ready if it happens again. Malivoire Winery has bought a shaker
table to dislodge the bugs from the bunches of grapes. They’ll also hire more people to
sort the grapes by hand.
Some people in the wine industry don’t like to talk about the multicolored Asian ladybug.
They’re afraid of tainting the reputation of their wines. Ann Sperling agreed to talk about
it because she thinks there wouldn’t have been as much damage to their 2001 vintage if
they had been better prepared. They haven’t had any big problems since then.
If another large invasion happens now, Malvoire Winery is ready. Ann Sperling hopes
other wineries will learn from their experience.
For the Great Lakes Radio Consortium, I’m Victoria Fenner.