PHOTO: S. Rae/Flickr
Kevin Fogle
December 5, 2016

For many households in North America, having a cut evergreen tree in the house is a great way to celebrate the upcoming winter holidays. The amazing scent of a freshly cut Douglas fir is intoxicating, as the citrus-like fragrance fills the entire dwelling. Trees can bring excitement to everyone in the household, especially families with children and grandchildren who eagerly await the promise of gifts beneath the branches of the evergreen.

An Unexpected Gift In The Christmas Tree

One holiday surprise that homeowners may not expect are the insects that occasionally arrive in your house on that freshly cut tree. Because your firs and pines were grown outdoors, they were exposed to a range of insects who sought shelter, food, and camouflage among the needles and branches of your tree. Because trees are cut in late November, typically in cool or high-elevation tree farms, most of the insects that once utilized the trees are now dead or overwintering elsewhere. However, there are two common exceptions that occasionally surprise the unwary homeowners: praying mantises and Cinara aphids.

Both insect species lay their eggs before the winter and when exposed to the warmth of your home will hatch thinking that spring has arrived. This often results in a multitude of immature insects on your cut tree. While readers are certainly familiar with praying mantises, the Cinara aphid is another story that leads to much confusion.

What Are Cinara Aphids?

Cinara aphids, aka conifer aphids, are some of the largest native aphids in North America reaching up to 1/8 inch long, much bigger than the common pest aphids found in vegetable gardens. Colored dark brown or black with long legs, these large aphids are often mistaken for ticks, leading to numerous myths about ticks in Christmas trees. First, ticks do not lay eggs in trees, and second, you can distinguish aphids from ticks by counting the legs—ticks have eight legs while all aphids species have six.

There is no treatment needed for either of these insects. The praying mantis nymphs will die off quickly due to a lack of food sources and through cannibalism. They cannot survive the cool weather, so there’s not much you can do to stop their untimely death. Use a vacuum cleaner to suck up the aphids, as they can stain carpets and floors when crushed. Don’t use insecticides in or around your tree, as they can be major fire and health hazards.

Reduce The Hitchhiker Risk

Not every Christmas tree will have praying mantises or Cinara aphids hitchhiking in it. Actually, it’s quite rare to find insects on Christmas trees at all, so I don’t wish to dissuade you from purchasing live trees in favor the plasticized monstrosities that fall under the label artificial trees. Just like cut trees, artificial trees can be home to a wide range of insects and spiders that they acquire while being stored in you basement, closet, or attic for eleven months of the year.

The best plan to lessen the insect load in your evergreen is to knock the tree outside before bring in it. This will remove spiders and beetles that might be overwintering within. Next, closely inspect your tree branches, inside and out, removing any mantis egg masses or bird nests that might contain mites or lice. If you do encounter a praying mantis egg mass simply trim the branch it attached to and leave it outdoors to let the eggs hatch naturally once warm weather arrives.


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