New Insects on the Horizon Thanks to Climate Change

New Insects on the Horizon Thanks to Climate Change

Part of Ep. 2104 Climate Change for Gardeners

Climate change has already brought new insects to Wisconsin and altered current insect populations. University of Wisconsin-Extension entomologist Phil Pellitteri explains what else is coming and how it will affect our gardens.

Premiere date: May 22, 2013

TRANSCRIPT+
Wisc Gardener Transcript: 

Shelley Ryan:

Plants and temperatures aren't the only things that change as a result of climate change. Insects are going to become more interesting as the climate continues to change. We are at DC Smith greenhouse at the Horticulture building on the University of Wisconsin Madison campus on a very busy street corner. I am with UW-Extension entomologist Phil Pellitteri, and we're talking insects and climate change. First, we should talk about the year 2012 which was kind of, we hope an anomaly, and yet from what I hear, as climate change continues temperature extremes from horrendous rain to horrendous drought and high temperatures, like we had in 2012, it may become more normal, may become more frequent. That caused some interesting issues with insects, didn't it?

 

Phil Pellitteri:

It was definitely the most insect specimens I've ever seen in a year in the lab. The dynamics there, things started early. We had very strong southerly air flows and so we had a month extra growing season. But really, what was more interesting is what came up in the spring winds. We saw a number of insects from down south insects that attacked baptisia. It's a Texas moth called the genista broom moth.

 

Shelley Ryan:

From Texas?

 

Phil Pellitteri:

I don't normally see that established up here. We had big flights of cutworms come up here. Insects that used to have one generation a year tried a second generation. Something like the squash vine borer took advantage of the longer growing season. So you see that short-term effect, because of the dramatic changes and the drought. Lots of spider mites, things like false chinch bug. I haven't seen that insect since 1988.

 

Shelley Ryan:

Wow, the last drought.

 

Phil Pellitteri:

Right, the climate effect of that. But what is kind of interesting then is looking at the longer term effects. That's somewhat different, because the dynamics there have more to do with the lack of cold weather in the winter and the creatures that are doing quite well because of that.

 

Shelley Ryan:

I'm curious then. Some of these critters that flew up because of climate change they might be able to survive and stay here?

 

Phil Pellitteri:

Yeah, it depends on the critter. You know, some of them if you're normally established in Florida and can't get north of there normally winters will take care of those. But I think the dynamic we're seeing-- I tease sometimes the governor moved us to Missouri and didn't tell us-- But the extent of ranges of southern insects that normally were central Illinois now, are well into the central part of Wisconsin. I can give you some examples of that. And some of them are good.

 

Shelley Ryan:

Oh, that's good to know!

 

Phil Pellitteri:

This creature is called a giant swallow tail. Giant swallow tails are endemic to Wisconsin. They breed on prickly ash, which we have quite a bit in the western edge of the state. Historically, if you got some decent cold winter weather they didn't do very well so some summers, they're very hard to find. It doesn't seem to be that way anymore. They really are quite common. I equate it to the high survival rates of the chrysalises, because of the lack of significant cold weather.

 

Shelley Ryan:

They're over wintering just fine.

 

Phil Pellitteri:

So that's kind of a fun one. Another interesting one is the praying mantis.

 

Shelley Ryan:

I haven't seen them in years.

 

Phil Pellitteri:

There are no native mantis to Wisconsin. It turns out there are two exotic species. One from China, the Chinese mantis, and one from Europe called the European mantis. They have one generation a year. They'd get through the winter in the egg case. It looks a little like a golf ball and is spongy. Historically, why it could survive is they freeze out. We had no established populations until about the last 10 years. Now we know for a fact that we've got breeding populations in the southern third of the state, and up in Door County. It's purely because they're surviving the winter, and the real reason behind that is the lack of 30-below and some of these other temperatures that really were quite commonplace at one time. But we just don't see them any more.

 

Shelley Ryan:

Another neat new insect that you and I have talked about are the giant cicada killer wasps that look scarier than all get out but aren't going to harm us. Those weren't here.

 

Phil Pellitteri:

Again, as a young entomologist, it was something I'd find in Indianapolis but you just barely saw any records here. Now they're so well established in the southern part of the state. In fact, we've done a piece on that in the past just to kind of get people used to what that creature is about.

 

Shelley Ryan:

So they'd stop running in terror because they're, like, about yay big.

 

Phil Pellitteri:

Another interesting one to look at there's an insect called euonymus caterpillar. It's a European insect that attacks burning bush and wahoo and other things in the genus Euonymus. Spring insect, it makes a lot of webbing. The first records we had were in the ‘80s out of Waukesha. But what we would see if you had a significant cold snap in the winter the little critters that over winter as first instar larvae on the bark died. So, I didn't see it move around. You get a couple mild winters and it gets to Madison. I saw it north of the Dells. Four years ago, somebody sent me a picture from Duluth of a burning bush hedge totally stripped and defoliated. So again, if that doesn't argue the lack of cold weather allowing insects to migrate farther north. That's a classic example of that situation.

 

Shelley Ryan:

Okay, I'm really "happy" now. I think I'm just going to keep moving as far north as I can go to get rid of the insects. But you also have one you wanted to mention that's not tied in with climate change but you kind of want people to be on the lookout for.

 

Phil Pellitteri:

Yeah, the next big pest critter is something called a marmorated stink bug, and it's a brown stink bug. It's confusing, we have native brown stink bugs here already.

 

Shelley Ryan:

I've seen this, but I haven't seen this one.

 

Phil Pellitteri:

Well, hopefully not. We have some small records of over wintering adults in three or four counties, but if you look what's happened out east it has become a major pest from two directions. One, it is a major pest of fruits and vegetables where its feeding causes distortions callusing, and abortions of the fruit.

 

Shelley Ryan:

Oh, great.

 

Phil Pellitteri:

In the fall, the adults invade people's houses like Asian lady beetle has done in the past.

 

Shelley Ryan:

Oh, really great.

 

Phil Pellitteri:

That combination makes it a super star and a super pest, and unfortunately, we expect this to continue to be more commonplace. It may take a few years to get to the levels it's been out in Pennsylvania and New Jersey, but it's coming.

 

Shelley Ryan:

So a lot of things are coming, some good, like the praying mantis a lot, not so great. We just need to be on the lookout and be prepared.

 

Phil Pellitteri:

Sometimes you gotta pretend that you moved 500 miles south because that's really what's starting to happen with the insect population.

 

Shelley Ryan:

Great, we can go swimming in November. Not. Okay, thanks, Phil.

 

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