Spiders: A Gardener’s Friend
Many people are afraid of spiders, but these beneficial predators are nature’s way of reducing garden pests.
Spider webs seem to be everywhere this time of year. Single lines floated almost invisibly across the gravel road as I walked to the mailbox. Naturally, I stepped into them. Watering the chrysanthemum on the back deck, I noticed other spiders had busily woven webs from post to post.
Wandering in the forest with my sons, we saw huge webs stretched between trees. There were particularly interesting because of the three-dimensional “boxes” in their centers. Autumn must truly have arrived!
In Washington, where I live, there are more than 800 different species of spiders. Up to 25 different species may live in your yard. Texas is said to have the most spiders, with 1,100 different varieties within its borders. Nationwide, there are approximately 3,500 different species of spiders, according to USA Spiders.
Most Spiders are Harmless
Don’t panic. Spiders are our friends, and their role in pest control is generally under-rated. Nonetheless, don’t touch them!
According to researchers at the Louisiana State University School of Medicine, most spiders do not bite humans. In fact, Washington State University, most spiders in the U.S. are beneficial. The spiders you see as you’re out and about in your yard or garden rarely harm humans.
Those that are harmful – specifically the black widows (Latrodectus, of which there are five species in the U.S.) and brown recluse (Loxosceles reclusa) – typically are hiding in obscure, dark places.
Pacific Northwesterners might add hobo spiders (Eratigena agrestis) to that list of medically dangerous arachnids, but the Centers for Disease Control and Prevention (CDC actually removed hobo spiders from its “dangerous spiders list” in 2017.
Spiders in the garden
There are three major categories of spiders, based upon whether they sit in webs to catch prey, forage for their prey, or lie in wait to ambush it.
In the garden, you’re most likely to see web builders. These beneficial predators devour or control a wide variety of insect pests, including aphids, mites, caterpillars, flies, wasps, beetles, grasshoppers, leafhoppers, whiteflies, thrips, and mealybugs.
If you see spiders in your garden, let them do their job. The more they work, the fewer pests you will have in your garden.
Web-builders are of the least threat to humans, according to Washington State University horticulturists. Their webs tend to be in bushes and on buildings or fences.
The Pacific Northwest also has jumping spiders that pounce on their prey. These hunting spiders often found in local gardens. Again, no worries!
Integrated Pest Management
Spiders, ladybugs, and other predatory insects are nature’s way of managing pests, and are an important part of an integrated pest management (IPM) strategy.
IPM takes a combination approach to pest management. It includes biological control, habitat management, cultural practices (how you tend your plants), and plant selection.
Spiders are part of the biological control aspect. Biological control uses the pests’ natural enemies against them.
To keep spiders and other beneficial predators in your yard, replace parts of your lawn with shrubs and bushes to provide the food, hosts, and shelter that beneficial predators need to thrive.
A diverse selection of plants – especially native plants – should be a significant part of your garden. Because they’re native, they’re already adapted to your region’s growing conditions and will help overwinter a variety of beneficial insects, especially if they are left undisturbed through the winter.
Also – and this is important – avoid (or at least minimize) the use of broad-spectrum pesticides. If synthetic pesticides are absolutely necessary, choose narrow-spectrum pesticides. Apply them only where they are needed (spot application) and during the early morning or late evening when winds have abated, to minimize pesticide drift.
Read the entire label every time you use a pesticide, and follow i’s instructions to the letter. That’s the law.
Spiders are just one of nature’s ways of maintaining equilibrium, proving a natural solution to every problem. So, when you see spiders weaving their webs, smile and know nature’s pest managers are on the job!
Many thanks for reading Where the Asphalt Ends.
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I love spiders because I've got a fly phobia!