Nasty worms/bugs hanging from my conifer trees in TN
I live in TN, and I have several conifer trees in my garden. Last year, hundreds of black cocoon-like shells were hanging from my conifers, and worms were coming out of the cocoons. It was pretty disgusting looking. I went to a local garden/nursery who told me what I needed to get to kill these mites. The guy also told me that these bugs (I don't recall the name) only come around every 30 years. I went to Lowes and got the spray I needed to kill these disgusting creatures. This was 2006. I sprayed the conifers -- two were salvagable but one was completely killed.
This year, summer 2007, these nasty bugs are back and have obliterated another of my conifer trees. :( I have some of the spray left to kill the bugs that are left, but does anyone know the following, please:
1. Although the conifer looks dead, do you think it will still grow back once the nasty bugs are dead?
2. Do you know what these bugs are?
3. Is there any truth to the fact these bugs only come every 30 years? In my case, they came last year AND this year!
4. Where are these nasty bugs coming from and how can I PREVENT them coming back ever again?
I love conifer trees (although I'm no expert), and I'm disappointed that they're being attacked.
Hope someone can help. Thank you in advance.