Since this problem is
rarely considered serious, it generally does not require
any treatment. However, here are some things to
consider:
1. Hand
Removal of Webs - If you have a few webs on a
strategically located ornamental tree, you can simply
remove the webs by hand. It is probably best to only
snip off the tips of the branch if this will not leave a
misshapen branch. Otherwise, just pull the tent apart
and brush the caterpillars into a container of soapy
water.
2. Use Bt -
Since these are true caterpillars (not sawfly larvae),
they can be killed by using the biological insecticide,
Bacillus thuringiensis (Bt). This must be sprayed
onto the leaves and eaten by the caterpillars.
Therefore, on small trees, it may be necessary to use a
stick to open up the tent to be sure that the spray
penetrates to the leaves. Another option is to keep a
close eye on trees that have been bothered by tent
caterpillars before so that you see the first signs of
feeding. This is before much of a nest has been begun.
3. Do Nothing - This will be the preferred option
in most cases. Fall webworm tends to be a cyclical
situation with some years experiencing a more severe
infestation than others. This is due to the presence of
natural predator insects which keep the fall webworm
from becoming too prevalent.
4. Insecticides - There are pesticides labeled
for use against fall webworm. The timing of the
applications must generally be made before the webs
become too extensive. Again, this is only warranted on
select ornamental trees which, perhaps, are near the
house or deck and the aesthetic damage is objectionable.
5. Do Not Burn the Tents Off the Tree!!!!! - All
this will do is kill the stem involved. This causes more
damage to the tree than doing nothing at all.
In
the spring, it is common to see silk-like webs in the
crotches of crabapple and cherry trees which are caused
by the 
