Keeping Pests Out of Your Halloween Decorations (and Off Your Porch Pumpkins)

A storage bin makes a particular sound when you open it for the first time in eleven months, a tired little sigh of trapped garage air. Out comes the fake cobweb, the light-up skeleton with one dead bulb, the witch hat that has been flattened in the same spot for three years, and occasionally a black widow who has been living very comfortably in the corner of the bin since last November. Halloween is a holiday about pretending to be scared of creepy crawlies. It would be nice if the real ones stayed out of it.

Decorations spend most of the year somewhere dark and undisturbed: the garage rafters, a shed, the back of a closet, the attic. That also happens to be an exact description of where a lot of pests like to live. A bin that hasn't been opened since last fall is less a storage container than a small apartment with a very long lease.

So open bins outside or in the open garage, not on the living room rug. Wear gloves. Lift lids slowly, look under the rim and in the corners, and shake fabric items out before they come inside. If you find droppings and want to know what left them, our droppings identification guide will help.

Costumes are the decorations most likely to get eaten, because they are often made of exactly what fabric pests want: a wool cape, a felt hat, a feather boa, real fur trim on a vintage coat. They also tend to go into storage the way most costumes do, worn for one long evening and then stuffed into a bag with whatever makeup, sweat and fun-size candy residue came home with them.

That combination is ideal for carpet beetle and clothes moth larvae. We covered those two in detail in our fabric pests article, so here is the short version: natural fibers, plus residue, plus months of being left alone, equals holes. Fully synthetic costumes and polyester fake cobwebs aren't much of a meal on their own, although they can still pick up spiders and other hitchhikers in storage.

If a costume or fabric decoration comes out with small holes, papery shed skins or silky webbing on it, bag it, keep it away from your closets, and clean or freeze it before it goes anywhere near your regular clothes.

The harvest look is great. It's also a lot of free food and shelter for bugs and rodents.

Anything you bring in from outside for a table display, like branches, leaves or pine cones, can carry insects in with it. Give it a shake and a once-over outside first.

Fall is when garden spiders are at their biggest. The orb weavers that started the year as specks have spent all summer growing, and by October their big wheel-shaped webs are strung across paths, between shrubs and over doorways. Drape a sheet of stretchy fake cobweb over the same shrubs and you have built them scaffolding. Within a few nights, real webs tend to appear right in the middle of the fake ones.

That's mostly harmless and occasionally hilarious. Orb weavers aren't aggressive and aren't considered a medical concern. It does mean the decorations come down with residents in them, so take outdoor webbing down with gloves on, shake it out away from the door, and don't stuff it straight back into the bin. The same goes for props that sat in shrubs or ground cover for a month: lift them, look underneath, and give them a shake. And if the eaves and entry have collected more real webs than fake ones by November, dewebbing, the physical removal of webs and egg sacs, is a quick one-off job.

Lighting plays a part too. Strings of bright white lights around the door pull in moths and other night-flying insects, which pull in spiders, which tend to make themselves known at the worst possible moment, right as you open the door to a group of trick-or-treaters. Warm-toned or orange bulbs, which suit the theme anyway, draw noticeably fewer bugs.

A whole, uncut pumpkin with a healthy stem can sit on a porch for weeks. The moment you carve it, you have turned it into an open wound. All that exposed flesh starts drying on the surface and breaking down underneath, and mold and rot follow. Southern California's version of October makes it worse. A string of warm afternoons, or a few days of hot, dry wind, can take a jack-o'-lantern from crisp to collapsing faster than people expect.

Then add a candle, which sits inside and gently cooks the pumpkin every evening. It looks wonderful. It also creates a warm, damp, sugary chamber that rots quickly and smells like dinner to half the neighborhood's insects.

A table centerpiece of mini pumpkins, gourds and apples is lovely, and it's also how plenty of houses end up with fruit flies in late October. Check the bottoms of everything every few days and get rid of anything soft. If fruit flies have already arrived, find the source first: the soft gourd, the forgotten potato, the recycling bin with a sticky bottle in it, or a kitchen drain that needs a scrub. A small dish of cider vinegar with a drop of dish soap will catch a few and tell you whether they are still around, but it won't fix the source.

If fruit flies keep coming back after the produce is long gone, the source is usually somewhere less obvious, like a drain, a trash area or the space under an appliance. That is where a professional look can save you a lot of vinegar.

The best time to prevent next year's surprise is the week after Halloween, while everything is out anyway.