Saturday, July 2, 2016

What do Gypsy Moth caterpillars like to eat?

Given that most caterpillars don't travel very far from where they were born, a better question might be: "what trees do gypsy moths lay their eggs on?  I suppose, since the female moths are flightless, these might amount to the same question after all!  Only in the last week or so have the local papers been really interested in the outbreak--possibly the worst in southern New England since 1981.  Of course, now the damage is done, and caterpillars are about ready to pupate.  We will be dealing with the moths in a few weeks.  

 (I remember having, as an undergraduate, the surreal experience of hearing the patter of raindrops (really frass) in bright sunshine where no sunshine should reach: the middle of an oak forest.)  Here, at least, the damage does not compare to that of 1981.  

This witchhazel has been hit pretty hard.  This is the only individual 
of this native shrub I know nearby, so its hard to say how general the damage is.

White oak is supposed to be a caterpillar favorite, but damage seems to be moderate here.  
But this may be mere appearance: white oak can put out a new suit of leaves pretty fast

The river birches have been hit pretty hard, but are recovering.

Black oak has suffered at least as much damage as white oak, and is at least as heavily infested.

The big surprise to me: I didn't see any damage to white pines, but suddenly there are tons of caterpillar cocoons in one neighborhood tree; maybe the damage is too high up to be easily visible.

Some trees appear to have suffered little damage.  (Appearances can be misleading: sometimes a tree looks good because it is able to produce new leaves as fast as caterpillars eat them.)

What do Gypsy Moth caterpillars not like?  


They appear to have no use for white ash.  Most ashes around the neighborhood
have leaves in pristine condition.  I haven't seen caterpillars in any ash trees. 

 Pignut and shagbark hickories are also mostly in very good shape.

 Quaking aspen suffered some damage early on, but has mostly recovered.

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