If most folks knew how many spiders were within a twenty five foot radius of where they are right now they would probably opt to live in a plastic bubble! Most of us are intimidated by these creatures. I have an average tolerance, but you'll never see me keeping one warm in my shirt pocket or play pet the tarantula in the local pet store. I do appreciate them, however. They are efficient hunters that play a positive role in my back yard and I'll even tolerate a few (little ones) in the house. They are a great excuse for all of the cobwebs present during my mother-in-law's semi-annual inspection tours each year!

Spiders come in all sizes in Michigan. They range in size from nearly microscopic (micro phantid by name) that prey on even smaller organisms in the soil litter to the almost palm-sized fishing spider. It is so name because it is found on quiet waters of lakes and ponds diving to capture aquatic insects and other creatures; even an occasional minnow. The largest terrestrial spider in Michigan is the garden spider. We have all seen this one. It commonly spins a large orb-shaped web in gardens and fallow fields.

Although there are over 500 species of spiders described in Michigan (2500 in the USA), this article will discuss a common spider found inside your house (house spider), the scariest-looking one that may wander in (wolf spider), and the big garden spider you might encounter in your back yard. For information on the North American Black Widow spider and the Brown Recluse refer to the article titled "Spiders of Medical Importance".

Damage
All spiders have jaw-like affairs tipped with venomous fangs. That's how they subdue their prey. Spiders cannot chew their meal so they secrete a substance that dissolves their captured prey to a point where they can ingest the liquid remains.

Spiders common to Michigan are not aggressive towards man, but some may nip us if they are being crushed, crowded or compromised physically. I say may because most spiders do not have strong enough mouth parts to puncture human skin. The pain associated with a spider bite is similar to being pinched. A red welt and some swelling may occur. Upon close examination you should notice two puncture marks. An individual's reaction to a spider bite will vary depending on personal sensitivity. On rare occasions, some people may have a violent reaction to being bitten by any spider (just as some people react violently to bee stings).

Spiders cause no damage in the household. However, all cobwebs are of spider origin. Cobwebs usually become noticeable when the web is abandoned and collects house dust. Abundant numbers of spiders in the household indicate the relative abundance of insects and other small critters that are spider prey. More are observed during warm weather than cold. 

Identification
Spiders are not insects. They have eight legs; insects have six. Their body is divided into two main regions; insects have three body regions. Spiders do not have antennae and all have jaw-like structures where you would expect to find the mouth (on the forward portion of the head). Spiders do not have wings; most insects do.

Daddy-longlegs are commonly mistaken as being spiders. Even  though they appear to be quite similar they are taxonomically quite different. Same Class, but different Order.

That cobweb-maker commonly found in the corners of rooms and window angles belongs to a family called house or cobweb spiders. More likely than not, that small brown or yellowish spider crawling on the ceiling or hanging around a light fixture (good place to catch insects) is a house spider. Unfortunately, I couldn't come up with a picture to show you.

Wolf spiders are sometime called ground spiders. This group of spiders forage for prey on the ground. They are usually dark brown to black in color and some species get fairly large, perhaps up to 3/4" in length. They enter homes quite by chance. They are active, fast moving spiders that look like mini-tarantulas. This usually causes the household great consternation. you can rest assured that they will not appear in any great numbers and once in the house they probably want to get out as soon as possible.

The garden spider normally inhabits grassy fields. They can sometimes be found in gardens and the shrubbery around the house. They are intimidating because of their large body size (over an inch long at time) and the great vertical orb web they spin. They are black and yellow or black and orange in color.

Spiders play a key role in ecosystems. They regulate populations of insects and other similar organisms. Without them, populations would soon be out of balance. In fact, spiders are often the dominant group of predators present in many habitats and frequently outnumber all of the other predators combined.

Integrated Spider Management
The goal of your spider household management plan should be to keep them outside, where they belong. Please be as tolerant towards spiders as you possibly can. We destroy them because we fear them. We fear them because we don't understand them.

Generally, good housekeeping practices in and around the house is the cornerstone to a domestic spider control program. Clean up woodpiles, trash, litter and other debris around the yard. Keep garages, basements, and crawl spaces clean, dry and uncluttered. Trim back shrubs so they are not touching the house. Keep the structure in good repair. Deny entry by doing routine maintenance and making repairs to cracks and crevices that invite small critters into your house. Patch screens and make sure there are good seals on all your windows. Especially those leading to the basement.

These measures will greatly reduce spiders and those insects and other organisms that spiders hunt.

If you vacuum room corners, registers and window frames regularly you are practicing effective control tactics. Most of us, however, do not think that often about vacuuming the basement. If you have a population you find intolerable, you must increase the frequency of vacuuming this part of the house.

If you believe you have a spider problem please follow these suggestions first. If the problem persists then you may want to consider a pesticide to knock down existing populations. Outside, we suggest diazinon spray around the outside foundation and adjacent one foot of soil. Ready to use chlorpyrifos or propoxur can be used inside on baseboards, cracks and door thresholds. Please do not use diazinon indoors.

Read and follow  instructions on the pesticide label. Heed all warnings. Check with your physician if you have any concerns regarding your personal health risk.