Bottle Garden caterpillar problem
 

I'm assuming they are caterpillars anyway. About 1cm long and a very pale
translucent greeny yellow. The bottle garden was bought from B & Q a couple
of months ago. I noticed one or two of them within a couple of weeks but
ignored them (Big mistake). Now there are loads of them and even the spider
who has taken up residence cfan't cope. Any ideas on how to get rid of them
without using chemicals. I've tried using a spoon etc to scoop them up but
the hole in the top is too small.

Any ideas appreciated

Thanks
Alwyn