For homeowners with indoor plants, the day of reckoning has arrived. It's what you did or didn't do in late fall that matters.

If you took steps in late November to raise the humidity in your home, especially around house plants, then you have succeeded in your first confrontation of 1991. As long as humidity continues to enrich the otherwise dry air, indoor plants will thrive.

However, if you elected to leave the home environment untouched back in November, then you have your work cut out for you for the next six weeks. Spraying indoor plants in January doesn't seem to make horticultural sense, but this is the only way you're going to conquer the insects out to destroy your plants.

Left alone, insects, specifically mealybugs, cyclamen and spider mites, will stampede over your plants for the next three months, leaving in their wake plants destined for the trash can.

Let us reconstruct events of the past eight weeks.

About the time you were carving the Thanksgiving turkey, you heard the first complaints about shocks from people walking across carpets and rugs indoors. Offices experienced similar problems, but most workers shrugged it off.

"Static electricity" is a hallmark of home environments where humidity has fallen to less than 20 percent. In dry conditions like this, mealybugs and mites happen naturally. Only by increasing the humidity can you get rid of these pests.

Before you think the worst has happened, check your plants carefully for evidence of insects.

Mealybugs. Most plant people have encountered these pests before. They are oval-shaped and white, generally one-third to one-fifth of an inch long. The body is covered with a waxy powder that hides the filaments that extend from all sides, including a tail. Mealybugs suck sugar from plant tissue, embedding their jagged mouths most often into stems and undersides of leaves. Mites. Not exactly an insect, two-spotted and cyclamen mites have four pairs of legs. Mites are best seen with a 10 power magnifying glass on undersides of foliage.

Two-spotted mites, generally called red spider mites, are one-fiftieth of an inch long, with two dark spots on their green, yellow or red bodies. In warm homes, the egg-to-adult transition takes 10 to 14 days. These pests attack leaves, leaving a tan and yellow stippling of foliage behind. Inevitably, leaves brown and drop, Sometimes, silken cobwebs appear on the undersides of discoloring foliage.

Fighting these pests isn't easy, so carefully explore your options:

The shower. Assemble all plants in the bathroom. Draw a large sheet of aluminum foil and cut half way through the side. Slide the foil over the pot of the first plant, turning the foil down on all sides to cover the top of the pot. Repeat this with foil to each plant. Adjust the shower head for warm-to-lukewarm water. Hold the plant on its side, then rotate the plant under the stream of water to dislodge pests from foliage and stems before you stand the pot in the tub so water courses over all foliage. Shower weekly for four or five weeks to eradicate the population.

Insecticides. If you have Safer's insecticidal soap on hand, use it. Gather plants in the bathroom to make things easier. Stand plants in the tub to avoid a mess. Spray tops of bottoms of leaves as well as stems and stalks. Repeat every week for the next four to five weeks to control all adults.

A recent introduction for insect control on indoor and outdoor plants is Tempo 2, a systemic insecticide with an outstanding track record in greenhouse and university tests. An advanced generation pyrethroid, Tempo 2 is destined to become your first line of defense for controlling insects, including mealybugs and mites on indoor plants. Only a microscopic amount of the product is needed when mixing pints and quarts of spray. Tempo 2 has a half-life of some 140 days. Once it has been mixed, it will retain its insect-control quality for longer than four months.

Outdoors, you will likely be relying on Tempo 2 to help control bagworms, box elder beetles, black vine weevils, flea beetles, gypsy moths, Japanese beetles, June beetles, lace bugs, leafhoppers, leaf rollers, midges, pill bugs, tent caterpillars, and thrips.

Safety suggests that any Tempo 2 sprays be made outdoors, preferably in a garage or porch vented to the outside. Spray plants thoroughly, adjusting the nozzle to provide a misting spray instead of large droplets. Because it is systemic, Tempo will be moved to all parts of the plant, even if you spray only the tops of leaves and visible stems.

A prerequisite of insect control is increasing the humidity in your home or apartment as well as that around plants. Repeat sprays or bathtub showers are temporary treatments because in poor humidity environments the pests will come roaring back. The only lethal blow to mealybugs and mites is raising the humidity to more than 30 percent.

If you don't have a humidifier built into your heating system, consider adding one now. Do-it-yourself homeowners can easily install the humidifier in one morning, thus providing a healthier environment for people and plants. Other homeowners should contact a heating contractor to arrange for prompt installation.

Your final options are double-potting plants and employing bowls of water to elevate the humidity locally around plants.

Double-potting. Picture the cup and saucer -- the cup as your potted plant, the saucer as a wide tray below the plant. Saucers should be as wide as the plant that it serves. At the garden shop you will find inexpensive plastic trays with the look of clay.

Begin by removing the add-on plastic drainage cap on the base of your existing pot. Turn this cap over and place it in the center of the tray. Atop this, place your potted plant, then fill the rest of the tray with colorful pebbles, stones or marble chips from the garden shop. Add an inch of water to the tray.

As the water evaporates, it will provide 25 percent to 30 percent humidity around the plant which is enough to prevent the return of mealybugs and mites as long as you are making periodic sprays to control adults. You can water these plants while they sit atop the tray, but water should never reach the top of the pebbles or stones, in which case siphon off water from the tray. Spraying foliage of plants is fine, but even if done daily, it will not deter mealybugs and mites.

Bowls. Scatter multiple bowls of water inconspicuously around plants to elevate the local humidity. A dozen bowls carefully placed around plants will work wonders, but check containers weekly for water. Remove bowls in late March.

Jack Eden is the host of "Over the Garden Fence" Sundays from 10 a.m. to 1 p.m. on WTOP Radio (1500 AM).