Cinara Aphid – Early Christmas Visitors
This is an updated version of an older post from 2017.
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 in Mills River has a great summary about this aphid which you can find here: Cinara Aphids on Christmas Trees in North Carolina
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 typically live in large colonies and will often congregate on the terminal, trunk, and upper setl of branches in the spring. However, as we move into the fall, possibly because of the 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 a chain-saw cutting down their hibernation home). Then, they end up on a lot somewhere waiting for a buyer. After you buy this magnificent Fraser fir and bring it home, it’s possible a few aphids may drop off as you drag the tree indoors. What typically happens is that after your put the tree 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 that latter 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 article, we really prefer that people avoid spraying insecticides on the trees particularly after they’re set up and decorated. For that reason, 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).
While many people might have a can of “Hot Shot” or other insect spray in their garage or a utility cabinet, it’s best to leave it there (and kept 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 insecticde – inquisitive little hands. Small children like to touch the tree (and then may stick their hands in their mouths). We don’t need that to include touching needles or decorations that may be covered with pesticide residue. Third – pets. Those of you who have cats know what I mean. Our feline friends 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 the litter box.
So, what can people spray? – Insecticidal soap is good choice. 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 I prefer to rely on EPA-registered products that have EPA-approved instructions on their use. 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 its needles too soon or become a fire hazard.
So, enjoy the holidays… Stay safe and aphid-free (and COVID-19 free, too)…….
Picture of Cinara aphid from Christmas Tree Extension – “Rogues’ Gallery of Post-Harvest Pests“