---

Many of our readers still buy or cut a live tree for the holiday season. Some buy natural garland, mistletoe, holly, etc. which add so much to the holiday season. Some of you may receive a live plant from a friend or loved one. However, some unwanted guests may come along also during this holiday season.

Andy Birkey, Entomology technician, recently wrote about some nuisance pests on Christmas trees.

Adelgids attack the bark on pines, especially white pine. The adults are tiny with soft, cottony outer coverings that create a white, fluffy appearance on the stems of the tree. Adelgids become active when the temperature reaches 50 degrees or when brought into the home. They should be noticeable when you purchase the tree. They are host specific, which means they don't transfer from the Christmas tree to the house plants.

Aphids are small sucking insects that range from 1/16 to 1/8 inches in size. They may hatch from egg muses that were not pruned out. These aphids are also host specific and don't feed on house plants.

Spider mites often become active when the temperature rises, as it does in a home, they are very small and may cluster together with some webbing present. They generally remain on the tree when active, but they can become a pest on houseplants.

Bark beetles feed under the bark of conifer trees. They can create a noticeable amount of sawdust as they burrow out of a tree. Bark beetles that over winter under the bark are usually 2-5 mm long and dark brown. They don't cause damage to furniture or household items.

Spiders sometimes seek shelter under the bark of Christmas trees. Although rare, they can be brought indoors on Christmas trees. Sometimes spider eggs are present on the tree and may hatch causing significant numbers. They are not dangerous to humans or pets.

Most retail Christmas tree outlets use mechanical shakers to remove dry and damaged needles. Shaking also dislodges many insects or spiders living on a tree. However, some may remain and be brought indoors. You may not be aware of bark beetles and the other insects that live inside the tree until after they emerge. Check over your tree once you bring it indoors and remove any insects that you find on the branch, branches or needles. If you miss some insects that emerge later just physically remove them. A vacuum cleaner works great at eliminating these pests. Pesticides are not recommended and never use flammable types of pesticides around conifer trees.

If you are lucky enough to receive a houseplant as a holiday gift, remember they were grown under ideal conditions. Find time to wash your houseplants so dust foliage won't attract insects and spider mites or interfere with the limited daylight reaching the leaves this time of year. Concentrate on the undersides of the leaves as well as the top.

There are many pests that love houseplants, including: mealybugs, thrips, springtails, fungus gnats, white flies, aphids, cyclamen mites, and I'm sure there are others. I decided that our problem is fungus gnats for two main reasons. First, they fly and can be mistaken for fruit flies. Second, they didn't leave a mess like a web, scales or excrement. Fungus gnats and their close relatives the shore fly, look much like fruit flies except they are black and smaller. Adults are quite harmless, but the larvae, tiny white grubs with dark-colored heads, may chew on plant roots. Their favorite food is organic matter (that is potting mix). Fungus gnats do little damage to adult plants, but can harm seedlings.

Adult females deposit between 100 and 150 eggs on the surface of the potting soil, close to the plant stem. These hatch in four to six days into larvae that feed on fungus, decaying organic matter, and plant tissue for about two weeks. They then emerge as adults in three to four days.

We are using insecticide soap called Attack, which claims to be effective against the gnats. We also soaked the soil of the plants with the solution to kill the larvae. I read that one needs to apply every week until the gnats disappear. One needs to be patient, as the adults may fly around the plants for some time. In a couple of the articles I read, it stated that common insecticides are not effective. For bad infestations, use Bacillus thuringiensis H-14 (Knock-Out-Gnats), a bacteria that specifically attacks fungus gnat larvae. Also, water plants thoroughly, but let soil dry as much as possible without letting plants wilt between watering.

+++++

I've already received several seed catalogs. I guess it's not too early to dream of spring! There will be a "Seed Starting" class Jan. 22, at the Coffee Depot in Lindstrom, from 2 -3 p.m. Watch for more details after the holidays.

---