Act by the time saucer magnolia blooms
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These caterpillars bug people out of all proportion to the
damage they do. They live in colonies, feeding freely by day
throughout a tree (most often, fruit trees including crabapples and
ornamental cherries). At night and on very gray days they gather in
a communal web in a branch crotch.
When their numbers are high, they can defoliate a tree but even
so, the tree is almost never permanently injured. Not, that is,
until the gardener comes out with a flamethrower of some kind to
burn out the tents.
Bugged to insanity
Who ever came up with that idea?! Think about it: Here are
caterpillars doing nothing more than noshing on ephemeral parts of
the tree, parts which only last the year. They don't hurt the wood
or the buds. If the plant loses enough foliage that it is tweaked
to produce more that same year, the caterpillars will have finished
and departed by the time it emerges.
And to get rid of them we burn the wood the tree took years to
Here are better approaches:
1) Get 'em before they hatch, before they do any
damage. All it takes is a bit of phenology,
details of which are provided to us as part of the lifework of Don
Orton of the Morton Arboretum in his book Coincide. We know that just as the
saucer magnolia buds are most pink and some are opening, these
caterpillars hatch out of the egg masses the moths laid last fall
on twigs, in crotches of the target trees.
The egg masses are easy to see (below) if you know to look for
them. They can be scraped off with a thumbnail. No fire or
chemicals required. Ground dwelling predators and fungi will snarf
up those eggs as soon as they fall.
The eggs in this mass have already eclosed -
hatched. You can see (below, right) that the individual cells are
We know about many insect emergence times as they relate to
various plants' development because age old wisdom plus a lifetime
of new observations have been compiled by Don Orton in a very well
2) Go out in the evening when they are all in that tent and
yoink them out of the tree. Throw them to the birds. Okay, maybe
you're more squeamish than our friend Cotton Harrison of Mary's Plant
Farm was, in which case you should wear gloves.
3) Look the other way. The damage is not
life threatening and the birds need insects
to eat. Besides, you have lots of better
things to do, right?
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We'd love to spend more time cross referencing the pieces of
this library. What comes to mind here are other tent making
caterpillars sometimes confused with tent caterpillar. It would
take just a little while to find and link to or post those photos!
We can do that with the aid of individual Sponsorships by those our
writing has helped.
Have we helped you? Can you help us, by becoming a Sponsor? It
takes only a simple email from our Sponsorship
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