Dear Cecil: As I was decorating my Christmas tree this year I began to wonder if I was putting myself at risk from insects. I don't like spiders much, and it would be even worse to have a Lyme-diseased tick bite me. Are Christmas trees fumigated, or are we bringing termites, etc, into our homes every holiday season? Doug in L.A.

Cecil replies:

Honestly, Doug, what a question! Don’t we have enough to stress about this time of year? Have some eggnog, sit back in your easy chair, and admire that tree. Now that you’re comfortable, here’s something that will answer all your questions.

It’s from the U.S. Department of Agriculture.

It’s called Christmas Tree Pest Manual.

It’s 179 pages long.

Now, Doug, if you’re going to shriek, next time wait till you finish swallowing the eggnog. You know how the feds exaggerate. Let’s start with something more calming. Here’s an article from the 1905 Washington Post. The headline reads:

LOADED WITH INSECTS

Christmas Trees Abound with Invisible Bug Life.

FORM PRETTY DECORATION

Now there’s a positive mental attitude for you — they’re not vermin, they’re a pretty decoration! The headline continues:

More Than Twenty-five Species, All Perfectly Harmless, Infest the Trees in Countless Millions and Add Material Beauty to the Ornamentation — Their Habits Discussed by an Expert.

Doug, please, put down that kerosene. Listen to what the article says about scale insects, a type of plant lice. Though “exceedingly destructive and harmful,” these bugs have the advantage of looking like white dots. “Think of it,” the above-mentioned expert is quoted as saying, “of buying a Christmas tree already decorated, radiant with hundreds of little shining white specks resembling snowflakes. They should make an ideal Christmas tree.”

Ah, Doug, now you’ve done it. It’s going to be hell getting those scorch marks off the ceiling. Let’s try another tack.

That 179-page USDA manual. True, it speaks in frank terms of the many insects, fungi, worms, and other horrors that can invade Christmas trees. There are aphids, spiders, spider mites, weevils, bark beetles, bagworms, budworms, and webworms, not to mention those scale insects. The gypsy moth and its cousins have plagued Christmas trees for more than a hundred years.

The manual omits praying mantises, but I happen to know they like to lay their egg cases on Christmas trees, and if the tree stays inside for a few weeks the eggs can hatch, releasing a cannibalistic horde of insects who have to eat each other because there’s no other food unless … Doug, this house of yours. Is there food in it?

Sorry, I’m going off on a tangent. The point I meant to make is that the USDA manual is mainly meant for Christmas tree growers, not buyers. Most pests can be controlled on the farm. The solution may entail pesticides, fungicides, or removal by hand. Trees suffering from a particularly heavy invasion of certain moths, weevils, midges, fungi, or what have you may be chipped or burned. Post-harvest fumigation is sometimes required for imported trees, which can mean toxic chemicals and higher cost.

Thankfully, drastic measures aren’t needed often. In a typical year perhaps one tree in 100,000 is bug-ridden. The critters are seldom harmful to humans. One grower’s guide notes that with adelgids, an insect found on white pine trees, you should “educate your buyers that this is a mostly harmless pest that is found everywhere including yard trees.”

Let’s face it, though. That kind of advice probably went over better in 1905 than it does today. At any rate, nobody bothered to educate SkipMagic, staff member emeritus of the Straight Dope Message Board, and his wife, Auntie Em. One year they picked out the perfect Christmas tree, carted it home, set it up and decorated it, and went to bed dreaming happy holiday thoughts. The next morning they came downstairs to find their tree covered with hundreds of silver threads, which extended from the tree in the living room to the chandelier in the dining room, and from there to a dining room window. From the threads hung tiny silver beads.

Sounds pretty, doesn’t it? You know what’s coming next. The threads were silk, and the tiny silver beads were a brood of baby spiders that had hatched in the warmth of the house. Skip and Em suppressed the urge to put the premises to the torch and instead got out the vacuum cleaner, thereby salvaging the situation, although it’s fair to say if you were a baby spider your Christmas that year sucked.

You can of course buy artificial and sidestep such issues, but you can never entirely put out of your mind the knowledge that the classic bristle-and-wire fake tree was originally devised by a manufacturer of toilet bowl brushes. Thus the eternal dilemma. You can take the antiseptic route and celebrate sterility. Or you can embrace biological reality with the knowledge that every so often you’re going to think: my God, this is gross.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.