The Q&A Archives: Black Worm On Blue Spruce

Question: My backyard blue spruce looks healthy, but close inspection revealed that new growth is being killed by what appears to be a black worm or slug. It is found when you pull off the brown new growth and squeeze it out. Also in the area where the infestation is noticeable, the needles in general look less dense and dry. This is a beautiful 15'+ blue spruce that I would hate to see die. What do I do to kill these destructive insects?

Answer: I'm only making an educated guess without seeing the pest, but I'll bet it's Spruce budworm. These larvae attack the foliage and buds of spruce and can be controlled with Bt (Bacillus thuringiensis) in early spring when the larvae begin to feed on old needles and before they enter buds. June to July applications will control larvae on new growth. To make certain that's the pest you're dealing with, and to learn about other control measures, be sure to take a sample to your local Cooperative Extension office. Phone (740) 368-1925. Good luck with your spruce!

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