Is this caterpillar a threat?

[franktrog]

Hey everyone!

I planted a weeping willow in our back yard early last fall and this year we were extremely happy when it started producing leaves. I happened to walk outside to check it yesterday and noticed a bunch of black specs over one part of the tree. Upon further inspection I noticed that it was swarming with a black and yellow spotted caterpillar. I thought it was cool, but now today I checked it and a huge section of the tree has been devastated by these caterpillars. Should I remove them? Also what kind of caterpillars are these?

Any light on this would be great!

Regards,

Frank

Here is a link to my photobucket album with pictures of the tree and caterpillars and a moth I found on it too.

http://s285.photobucket.com/albums/ll56/serihon/Caterpillars/

 

[RonsGarden]

This a common pest problem with all members of the willow family!
...and there a number of species that love willows.
Yours look like the Willow Leaf Beetle which is an import!
You are going to have to use an pesticide!
http://www.oldhouseweb.com/gardening/salix-insects.shtml

 

[franktrog]

Wow! Thanks for the heads up. I thought only butterflies and moths came from caterpillars, so somethings interesting learned for sure. Is this a threat we will have to keep an eye out for yearly or all year round as well?

Regards,

Frank

 

[RonsGarden]

There maybe two cycles of egg laying so after killing off the first round you will need to keep an eye open for the second round in a month or so and spray again!
And, yes, it will be a yearly chore!
Welcome to our forum Frank!