The tradition of bringing real trees indoors to celebrate Christmas dates back to the 16th century . However, these trees which bring joy and embellishment to homes also bring in undesirable crawlers that can put a damper on the holiday festivities.
The seven most common species of insects found on Christmas trees which are brought inside homes are: 1) spiders, 2) aphids, 3) adelgids, 4) bark lice, 5) bark beetles, 6) mantises, and 7) scales. None of these pests are invasive in indoor environments or harmful to humans.
If you find your freshly-chopped or potted Christmas trees infested with bugs, we are here to discuss the most common species of insects found on conifer trees, and how to appropriately deal with them!
A Christmas tree outdoors can harbor up to 25,000 insects which are usually dormant in Winter. The heat of an indoor environment can simulate Spring and trigger these insects to become active. There are no species of pests in Conifer trees that have been confirmed to be harmful to humans or pets .
While a few bugs that come from Christmas trees may be attracted to nearby light sources such as lamps or windows, most of them remain in the tree because they are dependent on the sap and on the other bugs which they feed on. As the tree dries up, the insects will naturally die as well.
It is generally advised to leave bugs on the tree. After taking out the tree, any bugs left inside the house will not survive for a long time due to unnatural environmental conditions and lack of food sources.
Spiders are predators of insects living in the Christmas tree. They are found on all parts of the tree.
Spiders found on conifers are usually not dangerous to people or pets. However, their eggs can hatch within days of taking the tree inside, releasing hundreds of tiny, gray spiderlings.
Spiders that come from outdoors will die shortly in an indoor environment.
Spider webs can be cleaned using a feather duster, while the spiders themselves can be vacuumed. Squashing them can leave small red stains on your furniture.
Aphids are crawling insects that suck on a Christmas tree’s sap. They may be brown, black, red, or green in color. They do not bite humans or carry diseases.
Aphids can be mistaken for ticks, but they have 6 legs instead of 8. They are usually only a few millimeters in length, often semi-transparent. You need to inspect the tree carefully to see them crawling near the sap area of the tree, between branches.
Initially, aphids are wingless when hatched but may produce winged offspring if a Christmas tree remains indoors for extended periods of time.
Aphids which feed on conifers are extremely host-specific, so they are not harmful to other house plants.
Aphids can be killed by spraying organic insecticidal soap on the foliage. If the infestation is heavy, you can take out the tree and hose down the needles. Don’t squash them because they can leave purplish or reddish stains on carpets.
Adelgids are tiny, yellow or purple insects similar to aphids which feed on sap and secrete a cottony wax substance. They are found on the branches and green parts of the tree.
Adelgids are sedentary, not leaving their host. The wool-like wax produced by adelgids can look like snow sprinkled on your tree’s buds and needle bases. Adelgids and their waxy secretions are harmless to humans.
Adelgids can be individually removed from Christmas trees using cotton buds soaked in rubbing alcohol. Insecticidal soap, neem oil, and diatomaceous powder also work well against Adelgids.
Another type of insect that might inhabit Christmas trees are Bark lice, also known as Psocids or Booklice. Bark lice are small, winged, and soft-bodied insects which can be gray or brown. They are found on the trunk, branches, or woody parts of the tree.
Bark lice do not damage conifers. In fact, they benefit the tree by feeding on organisms such as fungi, pollen, algae, and dead insects found in the bark and leaves.
Bark lice are not truly lice. They don’t bite or feed on people.
A strong spray of water should be sufficient in removing bark lice. The insects which fall can be vacuumed off the floor.
Bark beetles are cylindrical and brown, about the size of a grain of rice. They are found on the trunk, branches, or woody parts of the tree.
Bark beetles feed on stressed, dying, and dead trees. The larvae of beetles puncture the branches or the trunk of Christmas trees, pushing sawdust out of holes.
These beetles thrive on wood with high moisture content so they are not damaging to indoor furniture.
The trees can be shaken to encourage bark beetles to come out from their holes. The beetles can be individually plucked.
Mantises are green, leaping bugs similar to grasshoppers. They feed on small insects and as carnivores, they are harmless to Christmas trees.
Mantises produce brown, frothy egg masses attached to conifer twigs and branches. When Christmas trees are indoors, the eggs can hatch after several weeks. The lack of food indoors will prompt the mantises to cannibalize each other.
Adult mantises are big enough to be captured individually and released outdoors.Their egg masses can be scraped off.
Scales are insects that feed on plant sap. They are found on the trunk, branches, or woody parts of the tree.
Adult scales are unmoving and covered in a waxy coating, while their young are extremely small crawling bugs. When a Christmas tree is brought indoors, the crawlers can emerge after 2 weeks.
Armored scales can be scraped off while the soft-bodied scales can be wiped off with a damp towel. You may use insecticidal soap and neem oil to suffocate scales.
Here are a few tips to follow to avoid taking home pest-ridden Christmas trees:
Inspect your tree. Examine your chosen tree for any signs of diseases or discoloration. Check thoroughly on the underside of leaves, on the branches, and trunk. Make sure you choose a tree that has healthy green leaves firmly attached to the tree. Avoid trees that have bird nests in them.
Have the tree shaken or blown. Ask your local retailer or seller if they have mechanical shakers or leaf blowers which can be used to dislodge brown needles along with the bugs that usually hide in them.
Apply organic insecticides. You can spray diluted neem oil or insecticidal soap on the foliage. You can also sprinkle diatomaceous earth powder everywhere on the tree. Both of these can suffocate or dehydrate bugs that may be hiding in your tree.
Don’t use aerosol sprays. Aerosol and other chemical sprays are not only a huge fire hazard on living trees, they are also a health risk to your family when you display the tree indoors.
Wear gloves. When setting up your Christmas tree, wear gloves to protect your hands from any crawling bugs and from sharp needles. Keep your vacuum ready throughout the holiday season for any potential bug outbreak.
Insects such as 1) aphids 2) adelgids 3) midges 4) mites 5) weevils and 6) scales are the most common pests found on planted Christmas trees. They damage the trees by chewing on needles, tunneling inside trunks, sucking sap from foliage, and spreading organisms on the tree.
While insect pests on Christmas trees may be easily dealt with in their natural habitat, they can be invasive when the trees are transported to states or countries where they have no natural predators. Fumigation, radiation, and strict quality checks are carried out when the trees are distributed between borders.
Here are 6 common species of pests that you may find if you are growing a Christmas tree in your backyard [3- 6].
Damage: Aphids cause needle loss, and the eventual deaths of the leading shoot and the branch tips. They usually stay on their host but will move to other trees when the needles have dried out.
Characteristics: Mother aphids are large and bluish-gray. Offspring are small, greenish-yellow, and covered in powdery wax. Eggs are oval, pale tan, and coated with wax. Aphids secrete honeydew. There are at least 152 species of aphids found on conifer trees.
Examples: Balsam Twig Aphid, Conifer Root Aphid, Giant/ Cinara Aphid, White Pine Aphid
- Curled, twisted, or stunted needles
- Stunted young trees
- Black, sooty mold on stems and leading shoots
- Presence of bees, wasps, or yellow jackets
- Presence of sticky honeydew and purple stains
Active on: February to October
What To Do:
Scout for ants around the trunk and near the roots. Ants may protect the aphids from natural enemies and carry the aphids around. Look for eggs in April. Use labeled pesticides after eggs hatch, but before buds break. You can introduce harmless predators such as ladybugs, lacewings, and earwigs.
Damage: Adelgids cause needles to turn yellow and fall. Stumps will have reddish discoloration. Branches will grow poorly and lose flexibility.
Characteristics: Adelgids may appear as small, white cottony balls on the underside of needles.
Examples: Balsam Woolly Adelgid, Cooley Spruce Gall Adelgid, Eastern Spruce Gall Adelgid, Pine Bark Adelgid, Pine Leaf Adelgid
- White cottony masses
- Needles with yellow spots and crooked shape
- Flat tops or crooked terminals
- Swelling around buds, inter-nodes, and lateral branches
- Stiff trunk
- Dead shoots or branches
Active on: April to October
What To Do:
Scout the branches for swollen areas and white, cottony masses. Spray insecticides at a high volume and with strong pressure. Repeat after 1 week. Avoid shearing branches during June to October when crawlers are active.
Damage: Midges create unsightly galls on the foliage of conifer trees. They can also cause heavy needle loss, making the trees unfit for selling.
Characteristics: Midges are tiny flies. Their larvae mine the needles and are white or orange in color.
Examples: Douglas-fir Needle Midge, Balsam Gall Midge, Spruce Gall Midge
- Yellow or reddish-brown needles
- Gall formations or swelling at the base of new needles
Active on: March to May
What To Do: Spray insecticides, covering all buds. If the infestation is heavy, repeat after 10 days. Use emergence traps or sticky boards to capture adults. Remove heavily infested trees before larvae exit the needles.
Damage: Mites in conifer trees can cause heavy needle drop leading to naked branches, permanent loss of chlorophyll, and damage inside the trunk and near the base of the tree.
Characteristics: Mites damage trees during hot, dry weather. They feed on sap and they spin webs. Eggs are tan in color, appear in clusters, and have a single stripe on top.
Examples: Spruce Spider Mite, Eriophyid Mite, Admes Mite
- Rusty bronze needle bases
- Stunting and curling of needles or shoots
- Fine silk webbing at the twigs which traps dead mites, dirt, and other debris
Active on: February to October
What To Do: Look for spider mites and eggs. Needles may appear white or fuzzy. Beat the branches and use paper plates or light-colored surfaces to catch the spider mites. You may apply horticultural oils, dormant oils, superior oils, or miticides at 2-week intervals.
Damage: Weevils can damage conifer trees through reduced plant growth, premature needle loss, root damage, and death of twigs and branches.
Characteristics: The larvae of weevils are legless grubs that have curved C-shaped bodies. They penetrate the bark and eat roots. They target weak and stressed trees.
Examples: Pine Root Collar Weevil, Douglas-Fir Twig Weevil, Northern Pine Weevil, Pales Weevil, White Pine Weevil
- Yellow or reddish-brown needles
- Scallops or notches along needle margins
- Deformed branches
Active on: January to September
What To Do: Check for adult weevils under needles during cloudy days. Scout for larvae near the roots and crowns. Look for 1 mm holes in the trunk. Spray insecticides and repeat every 4 weeks until no adults are found. Disk and till the soil to disrupt their habitat. Avoid planting on dry sites. Remove infested trees.
Damage: Scales cause premature needle drop, stunted plant growth, and death of branches, shoots, or whole conifer trees.
Characteristics: Scales suck the sap from trees. The eggs of scales appear as white flecks, like powdery snow sprinkled on trees. They develop into red crawlers. Adults are 2 mm long, white or light-yellow in color, and are protected with a waxy coating.
Examples: Pine Needle Scale, Pine Tortoise Scale, Spruce Bud Scale
- Yellowing needles
- White-flecked or brownish foliage
- Dull-colored, weak, and droopy trees
- Dying shoots and lower branches
Active on: May to July
What To Do:
Introduce natural predators such as ladybugs or lace wigs. Apply dormant oil or horticultural oil. Remove severely infested trees. When crawlers are active, spray with an approved pesticide, followed by a second spray after 1 week.
- The most common species of bugs on Christmas trees which are brought indoors are Spiders, Aphids, Adelgids, Bark Lice, Bark Beetles, Praying Mantises, and Scales.
- All species of insects found on Christmas trees are not harmful to humans or pets inside the home. It is generally advised to leave them alone. They will naturally die as the tree dries.
- To get rid of pests on harvested Christmas trees, thoroughly shake your tree before taking it home.
- The most common species of pests found on planted conifers are Aphids, Adelgids, Midges, Mites, Weevils, and Scales.
- Insecticides, miticides, and other chemicals are used to control pest populations on conifer trees.
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