Now I know why my mugo pines "dropped" all their needles last summer! One morning I came outside and found them stripped bare. I thought it was the drought last year, as that was about the time it happened. Today I noticed less needles than yesterday, and a closer inspection revealed these greedy creatures (see attached photos). They're really creeping me out. A quick description: about 1 inch long, grey with black stripe down the side, black head, not fuzzy. There seems to be about 1 caterpillar per needle! Gross! Should I spray them with something? Will it matter? By the time I get down to the garden centre and back, they will probably have moved on to dessert! Somebody please help me!