Evil Western Spruce Budworms

I used to think that the most reviled creature on earth was the grasshopper. Last year we had an epic infestation. They ate everything, including our spruce trees.

But I’ve recently discovered something even more evil, more voracious, the Western Spruce Budworm (Choristoneura occidentalis).

I don’t have much capacity to hate. But I hate these things to the center of my being.

Budworms have a one year life cycle. The adult stage is a small mottled moth. After mating in mid-summer, females lay batches of eggs on the undersides of spruce needles. Larvae hatch about ten days later then hole up for the rest of the year. In the following spring, larvae migrate into new buds, forming silken cocoons. The destroy the new growth and cause massive defoliation.

This year, they’ve been going to town on our blue spruce. Our green spruce our relatively unaffected.

Now normally I’m not wont to use the nuclear option of pesticides. We drink from a well, our house resides on a bluff above the free-flowing Yellowstone river, and we have carefully created a bird habitat around our house. We don’t want to disturb any of these things. But watching our blue spruce getting savaged is just too much.

I sprayed our trees with Sevin today in the hopes of decimating the budworm cities. Without it, I think our spruce would be dead in the next few years.


  1. niceworm says

    you should try bio control with insect-parasitic nematodes. they are environmental-friendly agents.

  2. Lori says

    Did the Sevin work? I just found a mass of light green w/brown head, worms, on our Pinon. The mas was at the very end of the branch; if they would not have been moving, I never would have seen them. I cut off the entire branch, placed it in a zip lock bag & took it to our conservancy district. He said they were budworms & Sevin or a strong stream of soapy water should work. Said once they fall off the tree they can not climb back up.

  3. tharris says

    Sevin does work very well. Apparently, the best time to treat is when
    your pines first start budding out new growth. Still, treating later
    will get rid of the very voracious larval stages.

    I'm also intrigued by the idea of using soapy water. Knocking the
    worms off the trees could be very effective if there aren't many worms
    or your trees aren't too big.

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