Last night I ran across a photograph I took at Duke Gardens a few years ago of a light green spider on a Polianthes tuberosa flower. I’d seen them before on occasion, but didn’t know the name, so off to the internet I went.
As often happens, that search led to an article, then to related links, and on and on and on…..you know how it goes. I came across an article in which the writer was boasting about having solved a decreased yield problem in a vegetable garden which he had attributed to spiders. He opened with “Is your garden looking gloomy recently? Are your plants getting eaten up, especially by garden spiders and other bugs?” Say what?
He had sprayed and dusted repeatedly and it reduced the spider population but they continued coming back. The article recommended ladybugs as a solution for this “spider problem”. They prey on spiders, it claimed. He ended the article with this, “Lady bugs are nature’s natural defense against the enemy of your plants: the garden spider.”
Hmmmm… I’d always believed that spiders were a friend in the garden and I’d never heard that ladybugs eat them. I took Bees and Beekeeping instead of General Entomology in school. Is this where that decision bites me in the backside?
I read the profile of the author of the article; he claims to be “an avid internet user and keeper of much random knowledge.” His profile picture was a pile of hot wings on a plate. Why is this guy giving garden advice? Are some spiders actually pests? Does Mr. Hot Wings know something I don’t? Maybe there are some rogue spiders in his neck of the woods. I’m an open minded person, so I did some research to try to prove HIS case. I searched online for Spider Pests and got a reply asking if I meant Spider Nests. That said a lot right there.
Here’s the deal on spiders in the garden: Spiders are all voracious predators but they don’t eat plants; they catch live animals including other spiders, flying insects, invertebrates and some small vertebrates. They use venom to paralyze or kill their prey.
Once caught, the prey is liquefied by enzymes before being consumed. The one potential down side to spiders in the garden is they don’t discriminate when choosing their prey. They can catch and kill lots of garden pests but they may also dine on beneficial insects like butterflies and honeybees.
So, back to the garden that was sprayed and dusted only to have the spiders return – what was really going on there? The spiders were probably killed along with insects, both pest and beneficial. Once the spray wore off or was rinsed away, new spiders arrived as did new insects of all types. Mr. Hot Wings did advise against spraying chemicals, so I’ll give him credit for that. Ladybugs can’t hurt; if their prey is present, they’ll eat it; if not, they’ll move on. His advice was good, but not for the reason he thought. The reader is left with the impression that the problem was spiders.
Do ladybugs eat spiders? I don’t know. I’m not going to say it can’t happen but honestly, that’s beside the point. If there actually was a problem it was likely an aphid problem, and ladybugs love to eat aphids! Or possibly, there never was a pest problem at all – the spray of a preventative dose of pesticide may have killed pollinators thereby reducing the yield in the garden. Spiders were seen because spiders frequent gardens and are fairly obvious, especially when you walk into a web! I assume good intentions on the part of the article’s author. His experience led him to a conclusion and he didn’t question it. He shared the information to help others. I did post a comment in defense of spiders and thanking him for advising people to stop spraying.
Try not to make assumptions – look past the obvious; investigate through reputable sources – your county extension office is a tremendous resource. Consider the internet for what it really is. Anyone can post anything, accurate or not. University websites are great for this kind of information. Garden forums can be a help because chances are if someone on a forum says something incorrect, someone else will call them out on it – there will be discussion. Books on organic gardening, pest control and companion planting will also provide a wealth of information. Just try to stay away from those who claim expert status because they are a “keeper of much random knowledge”.
To protect your plants, keep them healthy by way of nutritious soil so they’ll be better able to ward off pests and diseases. Plant a diverse garden, including plants that will attract pests away from your most desired plants – nasturtium, for example, is a lovely plant that can attract aphids away from more important edibles. You can also eat the flowers!
Accept the fact that you are going to see some plant damage in a naturally managed garden – it doesn’t necessarily mean the plant is being hurt or killed. And don’t assume that the critter you see is a pest. Get to know your garden – the animal life in it behaves in predictable ways. Learn to recognize the pests that target your particular plants so you can tell the friends from the foes. Pesticides aren’t the answer – they’ll kill everything including the pollinators and upset the natural balance in the garden.
To foster the presence of beneficial wildlife in your garden, resist the urge to meticulously clean up – leave spent or dead plants or plant parts right there in the garden. Mulch your garden – wildlife can hide or build nests in it. In addition to providing shelter or habitat, these materials will decompose and add nutrients to the soil.
Oh, the spider in the picture that sent me on this investigative journey? After being sidetracked by my Arachnid Innocence Project, I did go back and get my answer. It’s a Green Lynx spider, Peucetia viridans. It’s found throughout the southern United States and is valuable because of its potential use in agricultural pest management.