Spruce Budworm Pupae and Moth
On June 26, 2015, Sandy found that one of our young balsam fir trees[1] in the yard was infested with these little pupae embedded in the needles at the tips of the branches. They were only about half an inch long, if that.
They were somewhat variable in color, with some more green and some more brown.
Given where they were found (in the new-growth buds of fir trees), I figured that they were probably spruce budworms (Choristoneura fumiferana), so we kept them until they emerged to see if that could be confirmed. And they started coming out of the pupae on July 1.
Ayep, that’s a spruce budworm moth, all right. The wing pattern looks like an exact match. We can see its proboscis slightly unrolled in this next picture.
Shortly after emerging from their pupae, most butterflies and moths will excrete this viscous liquid, which tends to be some shade of yellow, orange, or tan. Basically, its all the wastes that they couldn’t get rid of while they were bound up in that pupa for a couple of weeks.
Spruce budworms can be very hard on spruce and fir trees, because of the way the trees grow. Every spring, a bud at the tip of the branch pops open with the new needles growing on it, and if all goes well it turns into a fresh branch. If anything happens to that bud, the tree can’t just push out a new bud to replace it until the next spring. Since the budworms specifically attack these growing buds right at the time they are most vulnerable, a big plague of budworms can basically eliminate all the new growth for a year. And if this happens a couple of years in succession, it can kill the tree.
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[1] Some years ago, Sandy planted a number of Balsam Firs because she likes them for Christmas trees. They are mostly coming along nicely. Aside from the budworm infestation, that is.
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Quite a few of our trees have died from these guys.
Some small trees, but quite a few very huge ones. One of them is so rotten it could fall over any time.
It’s a shame really. :c