Dec. 9, 2004

Kiss me under the vascular plant parasite

by AMY STEWART

THE BIG INSECT-RELATED HOLIDAY STORY this year comes from Saginaw, Mich., where a receptionist named Marianne Luth unpacked her new artificial Christmas tree and noticed a line of tiny bugs -- brown fir longhorned beetles, to be precise -- scurrying across the carpet. Turns out that the tree, which was made in China, had a trunk covered in real bark, and the real bark was infested with real bark beetles.

Marianne had the good sense to return the tree to Ace Hardware and notify the Michigan Department of Agriculture. State officials laid the blame squarely with the Department of Homeland Security, which is short about 400 agriculture inspectors. As a result of this shortage, some evildoers -- mostly of the six-legged variety -- were able to slip past our borders. Marianne took it all in stride, pointing out that she got a tree with free moving ornaments.

I cut down my own blue spruce on a tree farm last year, and it came with moving ornaments, too: Diabrotica beetles, also known as spotted cucumber beetles. Like Marianne, I didn't get alarmed. After all, cucumber beetles aren't so bad. All they do is destroy cucumbers, melons, squash, beans, corn and roses, and spread bacteria wilt. Oh, and they're extraordinarily difficult to control organically. So what's all the fuss about? Besides, they're light green with black spots, and that makes them so adorable.

It was all I could do to keep from Napalming our living room. What was I thinking, bringing a live tree in the house? My garden will harbor Diabrotica beetles until the day I die. I'm screwed, Marianne, and so are you.

So much for Christmas cheer. Now I've started to eye all holiday greenery with suspicion, if not outright contempt. That wreath I bought at the hardware story had spiders in it. The poinsettia is harboring whitefly. And the mistletoe? That's a pest all by itself. Since when did kissing under a vascular plant parasite become romantic?

Well, since about the 16th century, as it turns out, but gardeners in those days can be forgiven for failing to understand host-parasite relationships. We, on the other hand, have no such excuse. Broad-leaf mistletoes like Phoradendron macrophyllum can suck the life right out of a tree by sprouting in the bark, forcing its root-like structures into the trunk, and living off the water and nutrients that the tree needs for its own survival. A mature mistletoe plant can grow to the size of small shrub, and all the while the tree it's feeding on gets smaller and weaker. Now, there's a metaphor for romance. Go ahead, sneak a kiss. I dare you.

Mistletoe makes itself at home in any number of common trees: Alder, birch, maple, walnut, oak. There's even a dwarf variety, Arceuthobium spp., that plagues pines, firs and other evergreens. Apparently the commercial possibilities of a mistletoe-infested Christmas tree are lost on forest rangers in the Sierra; they seem more concerned with eradicating the parasite than exploiting its market potential. (By the way, if you want to get rid of mistletoe, cut early and often. Get it out of the trees and throw it away. It's not a very sophisticated strategy, but it's all we've got.)

There's a charming old Victorian tradition involving a man plucking a berry from a sprig of mistletoe and presenting it to his intended before he claims his kiss. The berry-producing mistletoes, it might interest you to know, are all female. There are also male mistletoes, which produce pollen, but no one is much interested in those. Although the notion of a berry-laden female sounds more charming than a male that drops pollen all over the rug in the hallway, the fact is that the females aren't very well-behaved either. Some dwarf mistletoes wait until they are ready to reproduce, then the berries erupt so forcefully that they hurl seeds 30 to 40 feet in every direction. Abominable behavior, but it's about what I've come to expect from Christmas greenery.

This year, maybe we'll get a fake tree. The aluminum kind. Just imagine how festive the green Diabrotica beetles will look against all that shiny silver foil.

A note to readers: I decided to change the name of this column to Dirt. Why? Well, the Journal's sharp new design put me in the mood for a snappy new name, and Dirt seemed like the obvious choice. Hope you like it.

garden-related announcements and news to Amy Stewart
or write in care of the Journal at 145 G St., Suite A, Arcata, 95521.