tent caterpillers
- Subject: tent caterpillers
- From: L*@aol.com
- Date: Fri, 25 Apr 2003 16:34:18 EDT
Merri,
No need for desperation. Tent caterpillars are unsightly but they won't kill
a healthy tree. You need to be more concerned if your trees are already
stressed by other factors. The damage is done early enough in the season that
the tree, even if fully defoliated, can grow new leaves. Of course, that
takes a lot of energy and is not good for the tree. Repeated defoliation year
after year will certainly greatly weaken a tree and may eventually kill it by
making it vulnerable to other pests and disease. You should take care that
your infected trees get enough nutrients and especially water.
The best treatment is usually just to knock the webs out of the tree with a
cloth bag over a broom, a pole, a hockey stick or whatever else is handy.
Insecticides and burning are not necessary. This should be done in the very
early morning, late evening or when it is rainy, cool and overcast as that is
when the critters will be inside the webs. When you knock down the webs then,
you take the larvae out, too. If you just take down the webs while they are
out munching (usually when it is warm and sunny), they will just build more
webs and go on with their nasty little lives.
The adult is a flying moth (the most common species is brown with white). The
eggs overwinter on stems and hatch when the trees start to leaf out in the
spring. The new larvae crawl to the branch crotches and form webbing. They
leave the web during the day to feed on new leaves and return to the web at
night. They pupate in a cocoon and the flying adult moth hatches in the
summer and lays eggs (in July in the Midwest). Thank goodness, there is only
one generation a year. You can see the egg masses on the branches -- they are
dark brown and appear varnished.
The adult doesn't do any damage. It is the larvae that feed on the trees.
If you can remove the egg cases, there will be no larvae. Since you cannot
reach all of the webs, you probably can't reach all of the egg cases, either.
But removing as many as you can would be a help.
They are usually kept in control by natural predators, but it sounds like
there are not enough of those in your area. (Pardon the sermon here, but the
use of pesticides kills predators, too, and that is often why they are not
present when needed.) There is a biological control for tent caterpillars,
Bacillus thuringiensis var. kurstaki. Just go to a garden center and ask for
Bt for tent caterpillars and follow the directions on the bottle.
If you do decide to use a pesticide, and I wouldn't because you need all of
the predators you can get, keep in mind that it will not help when the larvae
are in the tents because the webs protect them. The coating on the egg masses
protects them, also. So, it only helps to apply insecticide when the moths
are flying or the larvae are out crawling. Otherwise you will only be killing
beneficial insects and that will only make your problem worse.
I hope this helps and good luck to you. --Janis
In a message dated 4/25/03 11:02:31 AM Central Daylight Time,
perennials-owner@hort.net writes:
> From: "Merri Morgan" <mmorgan@wcgnet.net>
> Subject: tent caterpillers
>
> Every year the infestation of these disgusting little pests is worse in the
> small wild cherry tree that shades some of my shade garden. I use Neem and
> burn out other tents with old t-shirts tied on a long pole, but I can't
> reach most of the tents. I live in fear that the tree will be totally
> defoliated or even killed. Is there any way to prevent the infestation in
> the first place? How do they get there? Is it from a flying critter or
> something that climbs the trunk? If the latter, would tanglefoot work?
> I'm
> getting desperate here.
> Merri Morgan
> Zone 5b, WV
>
> ------------------------------
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