Sunday, August 29, 2010

Grain or Meal Moth Infestation Out of Control - Help!

Indian meal moth trap catch
This question was sent to our 'Bugs site:

Briefly, the top floor of our small church building is simply full of grain moths (meal moths) and despite our best efforts, we seem to be losing the battle.
The problem came to light over a year ago, primarily in the kitchen. Problem areas were located and much work was done to clean everything in the area. Even at that time, traps were catching many, many moths (see photo) in areas that spread far from the kitchen. We did what we could, then the weather cooled and things seemed pretty quiet. We kept monitoring traps and replacing as needed, rarely seeing activity.
As the weather warmed in early summer, boy oh boy did we see a resurgence. Traps needed replacement as often as every 3 days. We continued to seek sources of infestation and clean, clean, clean. Then we realized our sanctuary -- a significant distance from the kitchen -- was heavily infested. Again, we've done what we can to clean and clean and clean. Sometimes we seem to be making progress, then another crop hatches as we feel back at "square one" as the saying goes.
We're basically monitoring and cleaning all areas of the top floor, and not making perceptible progress. Today we tipped over a piece of furniture and found the underside laden with worms, webs and eggs.
Other details:
  • Last year, in frustration, we had an extermination service spray. As you would guess, that was a waste of money.
  •  On the lower level of our building there is limited evidence of moths, though we have traps strategically placed.
  •  I am the coordinator of an emergency food pantry, located on the lower floor.  The pantry is not infested and was not a source of the problem.  We have mega monitoring in this area; it is closed off from everything else and was completely cleaned and painted within the past 2 months. Obviously my deepest concern is allowing the upstairs. problem to compromise the pantry and we're working hard to ensure that does not occur.
  •  It is my personal opinion that the moth problem began perhaps 2 or more years ago and no one noticed the problem quietly spreading far and wide.

The short answer is the primary moth infestation must be somewhere that is not obvious or you would have already found it. The larvae of these moths infest grains, seeds and other course material like cereal. A common and difficult-to-find source of moths is sometimes a cache of seeds/grain from a rodent nest inside the walls or ceiling. I agree that the moths are probably spreading out from this primary infestation to other parts of the building and I agree that it has probably been going on for awhile. I also agree that pest control is not the answer, unless they eliminate the rodents.

Pheromone traps (below) won't eliminate the moths but they may help to pinpoint the highest concentration and therefore where the primary infestation is located so definitely keep traps out. General cleaning won't help much either since these insects require a quantity  of seeds or grains not just crumbs. See Meal Moths & Traps for more information.

From your description of where you find moths I'd first suspect the second floor ceiling/attic space may be the source. Rodents often nest in these areas and will store seeds or grains. Your best bet, if I'm right, is to control and exclude the rodents, then the moths should go away. If you can actually find the nests, or caches of seeds/grains, and remove them the you'll speed things along.

Questions? Post a comment below.

Tuesday, August 17, 2010

Common Household Bugs

Which "Bugs" Are More Common In Homes?

hobo spider (drawing)
Almost every home harbours at least a few insects, spiders and mites. Most of these critters are harmless or can be managed in simple ways that don't use insecticides or other harsh chemicals.

In the lists below I've grouped those that are common in almost every home from those that occur only occasionally under specific circumstances, and those that may "invade" homes, usually from an outside source. There are also the so called "incidentals", that fly or crawl in through an open door or window by accident. The incidentals (moths, crickets, millipedes, and so forth) can be sweep up and deposited outside, or disposed of in the trash.

For all the others use the links below to find pictures, life history and least-toxic control strategies.

Common Pests
varied carpet beetle
  • Ants (several species) enter houses from outside but can also nest in walls and ceilings. Most can be managed with inexpensive baits but some stubborn colonies need more aggressive treatment. [more...]
  • Carpet beetles (see photo) are small, slow moving insects that infest stored foods and natural fabrics. [more...]
  • Dust mites are tiny, microscope mites that feed on the organic debris found in homes. These mites are so small that unless you are allergic to them you probably are unaware that they are even exist. [more...]
  • Spiders are very common in houses, most are harmless. Sticky spider traps are the best overall control for large spiders that wander inside homes like brown recluse spiders and hobo spiders (see drawing above).
Occasional Pests
house centipede
  • Clothes moths are small, tan moths whose larvae feed on and damage animal-based fabrics such as wool and silk. Adult moths are sometimes found fluttering inside closets [more...]
  • Cockroaches are world-champion scavengers and can survive on just about any scape of food we leave for them. They sometimes indicate unsanitary conditions and can be especially troublesome in apartment buildings. [more...]
  • Drain flies are tiny, somewhat hairy flies whose larvae infest bathroom and kitchen drains feeding on the gunk that develops in the pipes. Adult flies are found around sinks, both stages are harmless and can be managed with new drain cleaners. [more...]
  • Fleas (common only if pets are present) are the bane of every pet owner but can be easily controlled nowadays with topical flea treatments and insect growth regulators. [more...]
  • Fungus gnats are tiny, dark-colored flies whose larvae develop in potting soil feeding on roots and soil fungi. These flies can be present in large numbers in homes and are attracted to light, often aggregating at windows. [more...]
  • Grain mites, also called mold mites, feed on fungi and mold growing on damp surfaces. They frequently infest stored grains, especially if the grain is damp and moldy. The presence of mold mites in homes often indicates high humidity, dampness, or even a water leak. [more...]
  • House centipedes are scary-looking (see photo) but generally harmless inhabitants of damp basements. Sticky spider traps are effective if control is necessary. [more ...]
  • Pantry (meal) moths are small moths whose larvae infest stored foods like cereals and dry pet food. Adult moths are found fluttering in areas where food is stored. Use pheromone traps to detect and pinpoint infestations. [more...]
  • Psocids (booklice) are small, light-colored insects that are associated with damp, moldy areas such as old, musty books (hence the name "booklice"). They are not related to true lice and do not bite.
  • Stored product beetles include numerous species of beetles whose larvae infest stored foods, grains and sometimes natural fabrics. [more...]
  • Silverfish are small, silvery, fish-shaped insects that inhabit damp areas of homes. Silverfish can damage starchy/papery materials like books and papers but they are otherwise harmless.  [more...]
Pests That "Invade" Homes
hummingbird mite
  • Bird mites are also called nest mites or rodent mites. These mites infest the nests of birds and rodents where they feed on the blood of birds or rodents. These mites bite people as well when they are forced from their host animal's nest. They do not, however, infest homes long-term. [more...]
  • Clover mites are related to spider mites but are distinguished by a pair of very long front legs that can resemble antennae.
  • Cluster flies look like house flies and can enter houses in the fall when they seek shelter for the winter months.
  • Lady beetles (ladybugs) like cluster flies and boxelder bugs sometimes enter homes in the fall looking for a place to spend the winter.
  • Root weevils are beetles whose larvae feed on the roots of landscape plants. The adult beetles sometimes enter homes but cause no damage.
  • Springtails (Collembola) are tiny, primitive insects that live in soil. They are characterised by an ability to jump when disturbed. They can sometimes enter homes in large numbers but cause no damage. [more...]
Related Articles:

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** bed bugs, black flies, fleas, lice, biting midges, mosquitoes, ticks, carpenter ants, carpenter bees, wood wasps, powderpost beetles, termites, bees, fire ants, wasps, nuisance ants, pantry pests, cockroaches, carpet beetles, clothes moths, nest mites, chigger mites, scabies and mange mites, horse and deer flies, stable flies, boxelder bugs, cluster flies, house flies, fungus gnats, drain flies, lady beetles, silverfish and firebrats, vinegar flies, dust mites, venomous spiders, and delusions and phobias

Sunday, August 15, 2010

Discouraging Paper Wasp Nests

A question recently sent to our 'Bugs site:

I deliver propane for a living in NW Washington State and encounter a lot of paper wasps. My policy is live and let live and for the most part I can go about my job in fairly close proximity to even large nests (five inches diameter) and get stung rarely.

Lately I have seen a trend of the nests moving down from the inside of the tank lids to the plumbing, which is logistically not a great place for them to be, and is unfortunately an adequate reason to destroy the nest.

My question then is, do you know of some natural non lethal 'detractant' I could spray on the plumbing parts of the tank to make them non attractive for nesting? Something like cayenne or some herb, something that might give off a smell in the heat or????  The nests are ok in the tank lids - I understand it is a hot/safe place to build them - they just need to stay off the plumbing.


The paper wasp you are encountering is actually a fairly new "invader" species in the US called the European paper wasp (see link for picture). These new paper wasps make much larger nests than our native species and are somewhat more aggressive.

There are no sure-fire ways of discouraging nest building but threatening or dangerous nests can be easily managed with new low toxicity, plant oil-based sprays that should not damage the plumbing. These sprays (see the EcoSMART product below) are made from plant oils, not conventional synthetic pesticides.

One final thought: since these wasps only initiate nest building once a year in the spring, any areas that are treated should remain wasp-free for at least a year.

Questions? Post your comment or question below.