Caterpillars set to take over island
We seem to have a crazy number of caterpillar infestations on the island this spring. Have you seen the poor tree in front of the Gabriola Post Office? It has many times more caterpillars than leaves.
This nest of caterpillars is on Pequod Crescent, where a whole lot of trees are looking much worse for wear.
Filed in Gabriola Island,insects 21 Comments so far
21 Responses to “Caterpillars set to take over island”
cheryl on 25 May 2012 at 5:30 pm #
I’m glad you have posted something about these horrific little monsters.
I was in the 707 Acre park yesterday and was appalled by what I saw. It is being decimated by epic proportions. I would be willing to bet that every elder tree in the park has been and is being stripped and killed by this tiny invader. Some of the trees have so many cats on them you can’t even see the trunk of the tree right from the top to the bottom of the tree. It is so bad that our fruit trees on the the Island are in danger. And I’ve been told that other than picking the caterpillars off and killing them, there is nothing to be done about it. I suggest if you have elders or fruit trees on your property to take a look and get rid of any caterpillars you find. I think this is the worse I’ve ever seen it on Gab. I have already removed two nests from my Saskatoon bush. I have read that an outbreak can last up to 4 years.
skadhu on 25 May 2012 at 7:22 pm #
We hauled a couple of nests off trees last night and burned them.
Years ago I was in Prince George during an awful infestation. What I remember was being told that there had been a couple of accidents where cars had skidded off the road on a slick of crushed caterpillars. And visiting a demonstration forest. There were no leaves. It was impossible to walk without crushing them with every footstep. And you could HEAR THEM CHEWING. It was very, very creepy.
I believe that they do come in cycles and populations will crash after a really bad year—maybe I’ll see what I can find out about it.
skadhu on 25 May 2012 at 7:30 pm #
Lots of info here: http://www.na.fs.fed.us/spfo/pubs/fidls/ftc/tentcat.htm
Gabriolan on 25 May 2012 at 9:10 pm #
When I was a kid my dad used to attack caterpillar nests with the blow torch (while they were still on the tree). I remember being outraged because I thought of caterpillars as pets back then. :-)
At the Gabriola Commons there’s a huge (rose?) bush next to the cob wall. It’s infested, too – there must be at least 50 nests on that thing.
Gabriolan on 25 May 2012 at 9:15 pm #
Thanks, skadhu. I hope I’ll never come across anything like the infestation you saw in Prince George. That could give a person nightmares!
I’m pleased that none of our trees seem to be affected. But then, we don’t have fruit trees, so there is that.
Thanks for the link you provided. Very useful!
John on 25 May 2012 at 10:09 pm #
I am using a biological control that only affects caterpillars. It is the same bacteria that is used by certified organic farmers to control cabbage loppers and other caterpillars on food crops. Bacillus thuringiensis or BT is sprayed on the leaves in the evening. The caterpillars must eat the leaf while the bacteria is still alive. The damage is done in the gut of the caterpillar as the bacteria multiply. I sprayed it on a crab apple that was half eaten two days ago and again today. I could not reach the top of the tree with the little sprayer I had so my coverage could have been better.There are some that were dead and lots that were dangling from the nests branches and leaves. It appears to be very affective as a last resort.
Gabriolan on 25 May 2012 at 10:17 pm #
John – interesting! Where do you get that stuff?
John on 26 May 2012 at 7:38 am #
Evergro in Lantzville is where you can get the stuff. It comes in a 500 gram jar and mine has a best before date of June of this year. It has a shelf life of 24 months from when it was produced and a jar makes about 2000 litres and cost $45. You can buy it from a nursery in smaller quantities if they have fresh stock, always check the best before date as you are buying a living organism. I share my with friends.
Anon E Mouse on 26 May 2012 at 11:13 am #
This web site from Cornell University gives a bit more detail on solutions for tent caterpillars
http://counties.cce.cornell.edu/lewis/PDFs/Current%20Concerns/Tent%20Caterpillar%20control%20options.pdf
A couple of things from that article that might be useful – after you cut off the nests you can kill them in soapy water instead of having to burn them. I’d dump the soggy remains into the compost pile. (even more ecological if you have used soapnuts to make the soapy water) If you have a tree you want to keep from becoming infested or re-infested, put a turned-over band of burlap or some other kind of cloth around the trunk to trap the caterpillars crawling up the tree. They say to use a string, but I’d be inclined to attach the ends together with two of those heavy black paper clips to make it easier to take off and shake out into the soapy water and then put back on.
If you want to use BT, the kind you need is BTK (I notice in the article they also mention BTA, but I’ve never used that one. I think BTK is the commonly available kind) You might be able to find BTK for sale in smaller quantities than the 500g jar, I bought a much smaller amount of (I think) Safer’s BTK somewhere once. Might have been around 50g. Pretty sure it keeps for 2 years, but the advice to check the expiry date is good. I can’t remember which store, but I do recall it was a garden centre associated with a store – maybe Can. Tire, or one of the grocery stores with a seasonal garden centre. You can also use it for garden caterpillars (I think I used it for cabbage protection)
Greg on 26 May 2012 at 3:25 pm #
I used BTK on my apple trees and it was very effective. They have it at Wild Rose. Best to spray trees earlier with dormant oil but I did not get it done this year. OOPS.
John Peirce on 26 May 2012 at 9:08 pm #
This certainly is a bad year for tent catapillars. We have been removing eggcases from our orchard since February, and we are pruning nests twice a week as they develop. That’s in addition to having sprayed several times with Steven Levesque’s oil mixture.
My limited experience on Gabriola is that infestations only last one year. Our last bad outbreak was 4-5 years ago. I have one old full-sized apple tree that was completely defoliated to the point where the 12″ trunk was a seething mass – very unpleasant. But I reasoned that the tree has probably been there for 50 or more years and been through this before. Sure enough, we got a fine crop of apples the year after.
So, I’d be aggressive about protecting the trees and shrubs that are important to you, but trying to protect the trees in the 707 is a hopeless task. Let’s hope that again, this is a one year infestation! In any case, next winter check your fruit trees for egg cases when you prune.
John P
John on 26 May 2012 at 9:39 pm #
BT subspecies kurstahi is the one I have been using and is the only one readily available to my knowledge. I do have reservations of using an intervention in the balance of nature which could result in the evolution of a BT resistant tent caterpillar. I do not know the result of letting them run their coarse and consume all available resources. Unlike us who are beneficently consuming our resources in a prudent manner.
cheryl on 27 May 2012 at 9:25 am #
For several years agencies from the Canadian Forestry Services have come to Gab and put out moth traps for the Gypsy Moth but I haven’t seen one of those traps here for a couple of years or am I just blind. Does anyone know why this hasn’t been done in recent years or if there is a way to find our how to get them to ome and place traps out for next year or is this not a feasible solution. I’m I barking up the wrong tree so to speak. Or am I mistaken about the Gypsy Moth in that this isn’t the mother of the caterpillars.
John Peirce on 27 May 2012 at 12:12 pm #
The Gypsy Moth produces a different caterpillar (somewhat blue in colour) that really likes oak trees. They will decimate Garry Oaks. I have seen whole stands of oaks on the East Coast decimated by them, but there the trees come back the next year. In any case, totally different than the tent caterpillar.
I have not seen traps on Gabe in 8 or 9 years except the odd monitoring trap. They set out just a few, and if they capture even one male in one season then they blanket the area the next season. So I can only presume that the monitoring traps have been clean in recent years.
cheryl on 27 May 2012 at 3:00 pm #
Thank-you John I didn’t know that about Gypsy Moths. I learn much everyday.
Anon E Mouse on 28 May 2012 at 2:38 pm #
John, that’s interesting – I didn’t know that about the oaks.
Cheryl, to my eyes the caterpillars are actually pretty similar looking. The way you can tell for sure is that the gypsy moth caterpillars have paired red dots all down the body, and don’t form tents. If it is tent forming at this time of year, it’s a tent caterpillar. In the fall, there is something called fall webworm that also can form tents.
Here are a couple of links comparing gypsy moth and tent caterpillars.
http://www.dec.ny.gov/animals/7111.html
http://insects.about.com/od/identifyaninsect/a/cat-pests-id.htm
The 1st site also shows what the egg masses look like. I haven’t noticed those before, but it wouldn’t surprise me if Gabriolan, champeen spotter of weird things in the woods, had. Did you, G?
cheryl on 28 May 2012 at 8:35 pm #
Anon E Mouse, thank-you for the info I found it informative and very helpful.
danielle on 29 May 2012 at 5:25 am #
Our alders and the neighboor contains hundreds ofr nests, huges ones;
They are climbing the walls of our house now!!!!
In Belgium they had a pretty bad plague two years ago on a lot of oak trees and they had to spray them by helikopter.
it is our first summer here and I am pretty depressed about this.
The nests are mostly very high up in the tree, difficult to reach ;my neighboor lives in Vancouver and comes only once in awhile.
We could cut the low branches and burn the nest as they might come back next year otherwise i was told.???
Sarah on 31 May 2012 at 8:18 am #
I am soooo not into these caterpillars, I’d feel a whole lot better if I knew they would be turning into sparkling multi-coloured tie-dye butterflies or something…. now that would be magical!
Gabriolan on 06 Jun 2012 at 8:15 pm #
Sarah – if we’re going to have fantasies, we might as well have big ones. I’d feel a lot better if the caterpillars would turn themselves into casks of whiskey. That would give us much to look forward to!
But anyway, it could be worse. At least we’re not being invaded by poisonous spiders.
Just Another Weed Patch on 06 Jun 2012 at 9:59 pm #
It’s interesting to note that hornets and yellow jackets feed tent catepillars to their growing larvae. Perhaps last year Gabriolans trapped far too many wasps and hornets in their backyard traps and we’re paying the price this year with a bumper crop of catepillars?