Caterpillars on a Pine Tree

June 24th, 2009

The other day, well, almost 4 weeks ago (we’ve got a new baby, and so I’ve been too busy to blog), on my way to the hospital to see said baby I noticed large clumps of something on my Tanyosho pine. The pine hadn’t been looking too hot this Spring but I hadn’t looked too closely at it, but now it couldn’t be avoided.

Clumps of something had weighed down the tips of the needles to the point where they were drooping noticably, very obvious abnormal. So I took a closer look. It wasn’t a growth, it wasn’t needles with elephantisis, it was an infestation of caterpillars. They looked like the “tent worms” (gypsy moth larvae) that had defoliated so many trees around my parents house when I was younger (eventually forcing government intervention with airplane spraying).

I don’t, or rather I didn’t, often think of pines or other conifers as having pest problems. Their foliage is much more armored and it just didn’t seem like something they’d deal with. But these larvae had made short work of the needles on my pine and had defoliated maybe 30 or 40% of it before I noticed. This, is of course, much much worse than a critter defoliating a deciduous tree, because such trees are used to losing their leaves yearly and growing a new set in Spring. When most evergreens lose needles they usually do not grow back. Pines are somewhat of an exception, they do lose a small amount of needles every year and regrow them, but no where near 40%. So this is a big hit to the tree.

I googled it of course and turns out these are sawfly larvae, and the specifically target young or short pines, who would have thought, with all the other more vulnerable trees out there, the sawfly evolved to have their larvae target pines.

Couple the very bad damage, and the fact that I needed to get to the hospital (not for the delivery mind you, this was two days later) I didn’t bother trying to deal with it by hand (there were many dozens, but they were big suckers, so I could have, technically) or finding an all natural pest control (something I do usually think about, but rarely try, because they’re so hard to find to buy, and the one time I tried a home made concoction I killed every plant I tried it on). I grabbed trusty Sevin, and making sure no bees were present, I went to town. They rapidly started dropping and I haven’t seen one since.

2 Responses to “Caterpillars on a Pine Tree”

  1. Amy Greenan  Says:

    Yuck. Sawfly larvae got my roses this year, but I managed to handpick enough, and some soapy spray that I still got lots of blooms anyway… and now I am seeing the occasional aphid! Pests. :( I am sorry about your pine and hope it recovers from the onslaught!

  2. Amy  Says:

    Its a shame you didn’t have more time to research the little guys because you didn’t have to kill them. I know your trees looked bad, but they actually do come back very nicely. It seems that the sawfly larvae know that if they kill the tree, they leave no food for their progeny. They end up leaving the needles on just the very tips of most all of the branches, then move on to the next tree. Besides a sad looking tree for a season, they are harmless. We have over 100 White Pines bordering our property and have had a bout with them in the past, and of all the pines are still just fine.

    Congratulations on the new baby! They are the sweetest gift known!

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