Apparently COVID isn’t stopping some insects from traveling and visiting us for the holidays. We’re starting to receive pictures from people finding small dark-colored “bugs” in their homes. At this time of year, the problem is often what we call the “Cinara” aphids, also called “Giant conifer aphids”.
Dr. Jill Sidebottom at the MHCREC has a great summary about this aphid which you can find here.
Here’s a relatively short explanation and some advice that you can pass on to people who contact you. They get the name “giant conifer aphid” because (drum roll please) they’re big (among the largest aphids we have here) and because they feed on.. you guessed it… conifers… It’s not unusual to find them on Christmas trees, wreaths, and similar decorating material.
As noted in Dr. Sidebottom’s publication, the aphids are typically live in large colonies and will often congregate in the spring on the terminal, trunk, and upper setl of branches. However, as we move into the fall, possibly because of cooler temperatures, the Cinara aphids are more commonly found lower on the trunk and on the lower branches which means they are often hidden from view.
In these situations, the aphids have already nestled down peacefully on the tree for a long winter’s nap when there arose such a clatter – that being the sound of chain-saw cutting down their hibernation home) and then they end up on a lot somewhere waiting for a buyer. After you buy this magnificent Fraser fir and put it up in your house, the warmer indoor temperatures rouse the aphids who start wandering around and may drop off onto the tree skirting and the tiny Christmas village that you carefully put together under your tree each year. The aphids are strictly a nuisance, but extremely annoying, particularly when you squish them and they stain the skirting and the wrapping paper on your child’s gift. You can easily fix this problem next year by skipping the present and just give your kid the Amazon gift card which they really wanted in the first place.
So, what do you tell callers? As Dr. Sidebottom mentions in her publication, we really prefer that people avoid spraying insecticides on the trees once they’re set up and decorated. You might tell your audience ahead of time that it’s not a bad idea to hose down the tree before bringing it indoors. This is a quick (and non-toxic) way to remove a lot of the six-legged critters. You can also vacuum the aphids off the tree or when you see them on the floor or objects in the house, but you will also squash them in the process (and may lose some needles.)
If a caller mentions that they have a can of “Hot Shot” insect spray in their kitchen cabinet, tell them that’s nice but they should leave it there (and out of the reach of children). Don’t spray the tree with a typical insecticide. The reason is simple. First, if you spray while the tree is lit, the aerosol might ignite on the heated lights (if you have old-style incandescent bulbs) and set it on fire. Although that does get rid of the aphids, the ensuing conflagration could incinerate the tree, possibly the gifts and the tiny village under the tree (or worse, possibly your house).
Reason #2 why we don’t use an insecticide – inquisitive little hands. Children like to touch the tree (and then stick their hands in their mouths). We don’t need that to include touching needles or decorations that are covered with pesticide residue. Third – pets. Those of you who have cats know what I mean. Felines like to chew on needles and many of you have likely also experienced the joy of seeing needles and pieces of tinsel embedded in the cat poop as you clean out their litter box.
So, what can people spray? – Insecticidal soap. It’s readily available in hardware stores (“Safer” is one common brand). You can pick it up when you’re out there shopping (i.e., getting yet-another gift card). Some people will go online and find home-made recipes for insecticidal soap but we’re not legally in a position to recommend that; always rely on EPA-registered products. Insecticidal soap is very effective as a *contact* insecticide and does not pose a significant poison issue for people, kids or pets. It won’t leave a residual to kill aphids later but if you squirt the ones you see now, it will likely keep the problem to a minimum. And keep your tree watered properly so it doesn’t drop it’s needles too soon or become a fire hazard.