Aphids on Christmas Trees
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Susan Halbert, Susan.Halbert@freshfromflorida.com, Taxonomic Entomologist, Florida Department of Agriculture & Consumer Services, Division of Plant Industry and David J. Voegtlin, Illinois Natural History Survey
Several cases of aphid-infested Christmas trees have come to our attention. The aphids are a species of Cinara, a large genus of aphids that live on coniferous plants. Cinara spp. are large aphids with rotund bodies. Their superficial resemblance to engorged ticks has caused concern on the part of some homeowners; however, all Cinara spp. feed only on their host plants and are harmless to humans and pets. They do not transmit any human or animal pathogens. There is no need to treat the trees with insecticide. Cinara spp. can be recognized by their large (adults >1mm in length) hairy bodies. Like all insects, Cinara spp. have six legs (and two antennae) as opposed to eight legs on ticks. Their siphunculi are pore-like and located on flattened truncated cones, completely unlike the "tail-pipes" found on many other species of aphids. The mouthparts of Cinara spp. are long, extending ventrally to the abdomen of the aphids. The ultimate segment is long and lance-like. |
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Cinara spp. can live for several generations on cut Christmas trees. The infestations may arise in two different ways. Either the overwintering eggs of the aphids hatch under warm south Florida conditions, or aphids persist late in the season due to an exceptionally warm fall in the areas where the trees are grown. In either case, as soon as an infested tree begins to dry out ever so slightly, the aphids leave their feeding sites in search of a more suitable host. Aphids are capable of building up huge populations in a short time if conditions are right, so it is possible that there could be high numbers of aphids on some cut Christmas trees.
