Friday, March 30, 2007

Spring is a good time for garden slugs and snails!

Springtime is when garden slugs and snails can be the most damaging to your garden and landscape. Slugs, and their shelled cousins snails, begin their feeding activity in spring when the weather warms enough so plants start putting out new, tender growth. Both critters feed by rasping at plants producing ragged holes and shredded leaves. Other evidence of slug or snail activity is slime trails. Slime is laid down as these mollusks glide over rough surfaces.

Believe it or not slugs and snails do mostly beneficial things for gardeners and the environment in general. They are important recyclers in many ecosystems by reducing bulk plant material into a size that decomposes more readily.

The problem is that slugs and snails don't distinguish between natural plant litter and our valuable garden and landscape plants. So, occasionally, we need to discourage this "recycling" activity.

Gardeners have generally used poison baits or traps to reduce slug and snail numbers. Traps use a yeast or bran-type component to attract slugs and snails. Traps work fine but they take daily servicing and can be messy. Poison baits are easier to use but pose some danger because of the toxic nature of these materials. Older baits that contain metaldehyde can be especially hazardous.


Recently, new, low toxicity baits have been introduced that significantly reduce the hazards of slug and snail bait. Look for iron phosphate as the active ingredient (poison) of these new baits. Iron phosphate is generally safe for use where pets or wildlife might have access to the baits and it breaks down to a type of fertilizer if not eaten by slugs or snails.

See the slug and snail articles at 'Bugs for additional information about these garden pests.

Sunday, March 18, 2007

Ticks and basset hounds

Our 1 year old basset hound Minnie is a tick "magnet". She goes for a walk everyday in a grassy/wooded area near our home and likes to check out all manner rodent holes and such. If we don't treat her with a flea and tick medication (see below) she comes home with ticks attached to her head or neck area. Spring and early summer are peak times where we live but others may see peak tick activity in mid to late summer.

Ticks (left) are related to spiders. Unlike spiders, however, ticks are ectoparasites of vertebrate animals. This means that they feed on the blood of animals ranging from snakes to mammals, including us and our pets. Like other blood-feeding invertebrates, for example mosquitoes, female ticks must get a blood meal in order to lay healthy eggs.

Also like mosquitoes, ticks can transmit some important human and pet diseases while feeding. Lyme Disease is spread by the bite of ticks as is Rocky Mountain Spotted Fever and many others. Not all ticks carry disease but since some do you should take appropriate precautions with all tick bites.

First, remove ticks as soon as they are found on yourself or your pets. The proper "tick-removal" technique is important to avoid secondary infection of the bite site. See the tick removal article at 'Bugs for our suggestions.

Second, use repellents when you venture into areas where ticks are common especially during hot, dry times of the year. Ticks prefer areas with tall, grassy vegetation. DEET or picaridin-containing repellents are very effective against ticks. For pets some of the topically-applied flea and tick control medications are effective as well. We now treat Minnie with Frontline Top Spot every two to three months during "tick season" which is pretty much all year here in Oregon.

See the tick articles at 'Bugs for more information.

Monday, March 12, 2007

Honey bees disappearing???

In some parts of the US honey bees are disappearing. During 2006 many beekeepers reported that the bees from some hives had simply disappeared. When opened the hives were empty and the bees were gone for no apparent reason. Researchers have subsequently determined that these die offs have occurred before but they are not yet able to assign a cause. Some believe it is a disease, some believe pesticides are involved. The condition has been named Colony Collapse Disorder.

European honey bee and pollen sac

European honey bee with pollen sac

Beekeepers and farmers who depend on bees to pollinate their crops (mostly tree fruits, nuts and some vegetables) are rightly concerned. In recent years bees and beekeepers have faced a number of new "pests". Varroa
mite and tracheal mite are ectoparasites that attack adult and larval bees. Foulbrood is an important disease of honey bees, and Africanized bees, the so called "killer bees", are taking over European honey bee hives in the southwestern US. All in all this is probably not the best time to start a beekeeping business in the US!

A task force has been formed by USDA and Penn. State University researchers. I'll post updates as the task force reports their findings.


"The Fumigator" -- Selecting A Good Exterminator

Where's John Goodmanwhen you need him??? (In case you missed it, John Goodman plays "The Fumigator", a bug exterminator, in the move Arachnophobia about spiders gone wild.)

Most people refer to companies that provide pest control services as "exterminators". Exterminators prefer "pest control operator" or "pest control technician".

By any name a good pest control company is like a good car mechanic -- when you need one, you really need one. While our main 'Bugs site is dedicated to helping you solve many household pest problems yourself, occasionally you'll need professional help. If you are having trouble deciding if you can do it yourself or if you need help take at look at this page.

We've posted some suggestions for screening pest control companies for those (hopefully few) times when you need one, and some additional things to watch out for.

Try to avoid the "maintenance treatment" trap. Some companies will push maintenance contracts that call for periodic (once-a-month, every three months, etc.) re-treatments. These repeated treatments are almost never necessary, especially not during winter months.

See the article at 'Bugs for more information.

Sunday, March 11, 2007

Drywood Termite & Fumigation

Termites are the only insects that are able to digest wood (actually cellulose, the "structural" part of wood). Most termite species require either relatively wet wood (dampwood termites) or contact with soil moisture (subterranean termites). One species, however, the drywood termites live in colonies that are constructed above ground in dry wood and need no contact with soil moisture.

Drywood termites live in warm climates, in both desert and coastal areas. In the US drywood termites are generally found in a band along the southern and coastal states on both coasts (red area in map below).

map of drywood termites in the US

red area = both subterranean and drywood
termites; green area = mainly subterranean
termites

Damage from drywood termites can be extensive and is often hidden inside structural beams, flooring, etc. Because drywood termites lack connection to the soil they can be difficult to detect and treat.

Subterranean termites are usually controlled by treating the soil under and around structures with insecticide. Drywood termites, on the other hand, may require a very specialized and expensive procedure called fumigation (sometimes called "tent and fumigate").

For more about the biology and control of drywood termite see the pages at 'Bugs.


Thursday, March 08, 2007

Are natural insecticides always safe?

"A pesticide is a substance that disrupts or kills organisms that we consider to be pests, generally weeds, damaging insects, or microbes that cause disease. Natural pesticides are pesticides that are made by other organisms, usually for their own defense, or are derived from a natural source such as a mineral." from Natural Pesticides at LivingWithBugs.com

By this definition nicotine is a natural insecticide. Nicotine is produced by plants in the nightshade family of which tobacco is one species. Tobacco farmers have long-known that an infusion of water and tobacco leaves makes a powerful, and highly toxic, insecticide. Until recently nicotine was available as a commercial insecticide product called Black Leaf 40. Imidacloprid (Merit) is a modern insecticide based on nicotine chemistry.

chemical structure of nicotine
nicotine (drawing from wikipedia)

Nicotine is a powerful neurotoxin (nerve toxin). At low doses it acts as a stimulant while at higher doses it causes uncontrolled convulsions and respiratory failure.

Pyrethrum also is a natural insecticide. Pyrethrum is a product of certain plants in the genus Chrysantheum. It also is a powerful insecticide but is relatively non-toxic to other animals, including us. It is still widely used in products intended for homeowner use.

The point of the above is that calling something "natural" should not automatically imply it is safe. There are many natural compounds like nicotine that are highly toxic and you would not want to apply them around your home.

Insecticides are generally classified as organic (a product of a living organism), inorganic (usually mineral based like borate insecticides), or synthetic (manufactured). Organic insecticides can be further classified as plant-based or microbial. See this article for details about the different pesticide types.

Choose insecticides based on their toxicity and environmental persistence not on whether or not someone calls them "natural"; after all rattlesnake venom is natural, too!

Crane fly damage in lawns

Crane flies are medium to large insects that resemble large mosquitoes. In fact they are related to mosquitoes as both are "primitive flies"; delicate flies with long antennae. "Higher flies" like house flies tend to be heavier-bodied, stronger fliers with short, bristle-like antennae. Unlike mosquitoes, however, adult crane flies don't feed and are harmless. Crane fly larvae live in the soil and feed on plant roots.

Most crane fly species are confined to wet soils but a few have adapted to dryer soils which has allowed them to invade lawns and turf areas.

European crane fly

adult European crane fly

Crane fly life cycle

Crane fly eggs are laid in summer and larvae begin feeding on plant roots in fall. Larvae feed throughout winter and spring then pupate (pupae are the stage between larvae and adults) in early summer. Crane fly damage usually first appears during the dry days of summer as irregular patches. Grass dies because crane fly-damaged roots can't supply plants with water.

This brief life history points to two important periods when dealing with crane fly damage -- fall, when young larvae are starting to feed on roots, is the time to apply control measures, and mid-summer is when damage is likely to be seen.

For current crane fly control suggestions see our article at 'Bugs.


Wednesday, March 07, 2007

Put a barrier between you and dust mite allergen

Dust mites feed on the organic part of house dust (often, mostly skin flakes from us!) and then excrete an allergen, a substance that causes an allergic reaction, that can stuff up our nose or even lead to life-threatening asthma. Even if you could eliminate all dust mites, which is unlikely, their allergens would remain in bedding, carpets and other fabrics where dust mites live. When these fabrics are disturbed they release allergens into the air.

One of the best ways to prevent an allergic reaction to dust mite allergen is to put a barrier between you and the allergen, especially at night. If the allergen never gets airborne, it can't end up in your nose!

Since mattresses and pillows are a prime source of dust mites and dust mite allergen one solution is to cover them in special fabric that separates you from the allergens. Until recently these fabrics were made of plastic and tended to be very uncomfortable. Newer microfiber materials are more "cotton sheet-like".

See more suggestions for dealing with house dust mites at 'Bugs.

Friday, March 02, 2007

Insects that eat dirt - white grubs and lawns

White grub is the common name for larvae of scarab beetles like Japanese beetle, chafers and May/June beetles. White grubs feed on roots of grasses and can do considerable damage to turf grass. Because white grub larvae consume dirt along with plant roots their digestive track (visible from the outside) is usually packed at the back end with soil particles (see photo below).



White Grub Larva Photo by Steven Katovich,
USDA Forest Service, www.forestryimages.org


Professional turf managers, like golf course superintendents, generally use conventional insecticides such as imidacloprid to manage white grub populations. Homeowners can use less toxic materials because their tolerance for white grub damage is usually higher. Milky spore (milky disease) and entomopathogenic nematodes are two least-toxic choices.

See this article about biology and control of white grubs for additional information.