Tuesday, February 13, 2007

House inspections for water damage & insects

Regular inspections of the exterior and interior of your house are one of the best ways to protect your investment and avoid costly repairs. Basic home inspections can be done by homeowners themselves and don't take very long to complete. Inspections should be done at least twice a year, once in winter and once in summer.

The summer inspection should be done early in the day to avoid the heat of the afternoon when pest insects may go into hiding. Slowly walk around the exterior. Look for evidence of insect activity on the siding and especially the area where the siding overlaps the foundation. If you find large ants "trailing" into or out of the house capture a few for identification. Also check under the house, if possible, for termite and powderpost beetle activity.

Anyone who has watched the TV show "This Old House" knows that water damage is far more important than insect damage in most situations. Winter is the best time to inspect for water and moisture problems. Again, walk slowly around the structure and look for water wicking up the foundation from saturated soil. Overflowing gutters are another source of water damage. Also, check structural wood for evidence of dry rot and mold damage (this can be done during the summer inspection as well).

Keep notes from all your inspections so you'll have a record of when the last inspection was done and what you found. See the home inspection pages at 'Bugs for more information and a form to help with keeping records.

Saturday, February 10, 2007

Garden Books for 2007

Rodale just published this update for the 2007 season. This excellent resource covers insects, diseases and weeds in an encyclopedic style.

Rodale's Vegetable Garden Problem Solver

Late winter spider mites and spruce aphids

With spring still a month or so off most people are not yet thinking about landscape and garden pests. However, there are two pests that occur on conifers (evergreen trees and shrubs that bear cones such as pine, fir, and spruce and arbovitae) that deserve your attention before spring weather arrives.

Spruce spider mite, Oligonychus ununguis, is the most important spider mite pest of conifers and can severely damage some host plants. If, for example, you've ever seen an Alberta spruce with large patches of dead needles the damage was likely done by spruce spider mites. Spruce spider mite is especially common and damaging on conifers that are drought stressed or, ironically, water logged.

Spruce spider mite spends the winter months as a small reddish egg (below) on branches and needles. These eggs hatch in early spring to become the first generation of plant damaging mites. Look carefully with your hand lens in late winter and you'll see the eggs on infested plants. If you find eggs late winter is a good time to treat this first generation of mites and significantly reduce damage that will otherwise occur by summer.



spruce spider mite eggs on arbovitae

Infested plants can be treated with horticultural oil that will smother overwintering eggs without harming plants. See the spruce spider mite page at 'Bugs for more information.

The second landscape pest to watch for in late winter is spruce aphid. If you've seen spruce trees with missing needles below the branch tips the damage may have been caused by spruce aphid. These tiny aphids start feeding in late winter and disappear by spring when only their damage remains to be found. These aphids can be effectively treated like other aphids with insecticidal soap but treatment must be done in late winter, not summer.

So, get out there and start gardening by looking for these winter garden pests!

Thursday, February 08, 2007

Natural botanical insecticides and pesticides

Pesticides are not all created equal

I'm usually not very enthusiastic about insecticides in general and I almost never suggest that you use them indoors. However, there are times when a carefully timed application of insecticide will bring an otherwise out-of-control pest situation back to tolerable levels.

Until recently homeowners had relatively few options when it came to safe and effective pesticides for use indoors. The only available pesticides were either a messy, smelly aerosol spray or an equally smelly powdered insecticide. Gardeners have a few more options like insecticidal soap and neem oil (see below) but even here the choices were limited.

Fortunately, times they are a changin' (apologies to Bob Dylan). There has been a real movement in the last few years toward natural pesticides, those derived from natural, not man-made, sources. And, pesticides that are safer for the user and the environment - the so called biorational pesticides. Not all natural pesticides are biorational and not all biorational pesticides are natural. The classic example is nicotine, the active ingredient in the tobacco plant. Nicotine is a natural pesticide because it is derived from a living plant but it certainly is not biorational because it is so broadly toxic to both plants and animals.

There's now a new category of natural pesticides called botanicals that meets both criteria of low toxicity and low environmental impact while being effective and easy to use. Technically speaking botanical pesticides are not new. Pyrethrum is one of the oldest natural plant products used as an insecticide and neem oil, from the neem tree, has been used for its insecticidal and medicinal properties for hundreds of years. What's new is the combination of plant essential oils in different formulations (aerosol, dust, wettable powder, liquid concentrate) that can be used in a wide variety of pest control situations.

Why do plants make essential oil pesticides?

Plants make essential oils, like clove oil and peppermint oil, as defense against their animal and disease-causing enemies. The oils are made in special gland cells where they can be released in response to feeding by an herbivore or attack by a pathogen. It makes sense that these same compounds could be used as insecticides and fungicides when extracted from the plants. In small doses some of these same essential oils are used for fragrance or flavor.

Are they safer than synthetic pesticides?

No pesticide is 100% safe and non-toxic. However, the margin of safety for botanical pesticides is generally much higher than older synthetic pesticides. Most "pesticide" products in the US require testing and registration by the Environmental Protection Agency (EPA) to ensure they are both effective and safe, when used as directed on the product label. Some of the new botanical pesticides are so low in mammalian toxicity that they are exempt from EPA registration.

Bottom line: if you use an insecticide indoors consider using one of the new botanicals instead of the older synthetic pesticides. They are both effective, much safer, and even smell better! The only downside is that they are somewhat more expensive but this should encourage you to use less! Use the link below for more information.

Tuesday, February 06, 2007

Scabies and mange mites

drawing of a scabies miteWhat causes scabies and mange?

Both conditions are caused by a tiny mite (drawing left) that burrows into the skin causing irritation and intense itching.

Many mites (tiny, eight-legged animals more closely related to spiders than to insects) cause skin irritations and allergic reactions. These include house dust mites, grocers itch mites, chiggers or red mites, and several different fowl mites.

Only one mite, however, actually burrows into the skin. These are scabies, or the human itch, mites. In cats and dogs we use the term mange to describe two different mite infestations. One of the mange mites is the same one that causes scabies in humans.


What does scabies look like?

Scabies mites are very small (female: 1/60"). They burrow into and feed under the skin. They spend their entire life cycle on the host, but can survive off-host for up to 10 days, if conditions are moist. For this reason the mites can be transmitted by infested clothing, towels, bedding, and so forth. Burrowing and feeding causes intense itching that when scratched, may lead to infection and open wounds. Hard, pinhead-size pimples containing a yellow fluid may form over infested areas. You may also see faint grayish or reddish lines under the skin.

Where does a scabies infestation come from?

Transmission of scabies mites usually is by close contact with infested individuals. Suspected infestations should be directed to a physician. This is a medical problem for the most part and cannot be handled by pest control in the home. Very effective topical lotions are available to treat scabies outbreaks. Treatment may be repeated at 3-10 days to kill mites hatching from eggs, but follow medical advice in all cases. Clothing and bedding from an infested individual should be carefully laundered or dry cleaned.

Use the links below for more biology and control information.

Sunday, February 04, 2007

Head lice and pubic lice nits

head lice and a nit attached to hair shaftWhat are lice nits?

As every parent of a school-age child probably already knows head lice are tiny "bugs" that infest the scalp and cause a lot of itching and irritation. They can affect all kids, everywhere, and can be very contagious. They are, however, really (really!) less of a medical concern than many people believe, but that argument is for another blog article. This post is about the eggs, or nits, that lice lay and what exactly the nits look like.

Nit is another name for egg. Both head lice and pubic lice (a related species that infests areas of the body where course hair grows like the groin and chest) attach their nits to the hair of their hosts (see drawing above and photo below). The nits are actually glued to the hair shaft close to scalp because they need the warmth and moisture that comes off the scalp in order to develop properly. Nits are attached so tightly that normal washing, combing, or brushing won't remove them.

Nits hatch quickly (7-9 days) under normal conditions so any nit that is more then about an inch away from the scalp is probably already hatched or is dead. As the hairs grow the attached nits (alive or dead) move away from the scalp with the lengthening hair. There's some debate about how far away a live nit can be found from the scalp. Some people say 1/4" while others say "more than an inch". The difference probably depends on local climate and perhaps differences in lice populations. Regardless, just realize that it is difficult to tell the difference between live nits and dead or hatched nits.

photo of lice egg on hair shaftEffective lice control must include "nit-picking" and combing to crush or remove these eggs (see photo left). If lice eggs are not removed they will hatch in a few days and start the infestation all over again. Combing with the proper lice comb is the best way to remove nits and there are now effective combing aids that make this job easier. Use the links below for more information about lice and lice control.


Saturday, February 03, 2007

House dust mites

What is house dust?

Obviously the answer depends on where you live and the season of the year. In general, however, house dust is composed of ash, cloth fibers, hair, plant pollen, human and animal skin, soil particles, and fungal spores. In many households, human skin flakes make up much of this flying debris. On average, an adult sheds about 1/2oz of skin every day!

What are house dust mites?

House dust mites are tiny, nearly microscopic mites that feed on the organic parts of house dust.
The mites live in fabric and bedding and for many people go completely unnoticed. For some people however dust mites can cause moderate to severe allergy.

The allergy is caused by bits of the mites themselves that become airborne, and mite feces. What goes into dust mites as a flake of skin and hair comes out the other end as an allergen that can stuff up your nose, launch a severe allergic reaction or even trigger asthma. House dust mites are not the only source of allergen in our indoor environment but they may be one of the most important.


Dust mites take about 1 month to develop from egg to adult under ideal conditions. Growth occurs between 50 and 90 degrees F. and they require fairly high relative humidity (60-90%). This need for moisture is why dust mites tend to be more numerous in the spring and fall when indoor humidity is a little higher. Winter heating dries out houses and therefore reduces dust mite numbers. House dust mites do not bite or otherwise cause harm.

Control exposure to allergen and treat the allergy

If you are not bothered by dust mite allergy then there's no need to do anything. However, if allergies are a problem there are two things you can do that might help. First, try to limit your exposure to allergen by removing as much fabric from your living space, especially the bedroom. Use mattress and pillow covers to place a barrier between you and allergen contained in bedding. Second, medically treat the allergy (see your allergist or other health care provider).

Do not try to control house dust mites with insecticides! This will only make matters worse because allergies can make your body more sensitive to the irritation of insecticide exposure.

Use the link below for more information about house dust mites and ways to deal with the allergies they can cause.