The gardening world is divided into 2 parts: those who are very happy with pesticide bans protecting the health of citizens by banning dangerous chemicals from our yards, and those who are angry at seeing their favorite pesticides outlawed. But no matter which side of the fence you’re on, you still have to abide by the rules or risk hefty fines. So…
While in the majority of cases there are essentially equivalent “green solutions”, some people may be surprised to discover that this is not always the case.
The Perfect Lawn Syndrome
Homeowners caught with dandelion-infested lawns, but who can’t find any “treatment” for their problem, are especially at a loss. In fact, herbicides such as glyphosate, banned in more and more municipalities, and soap or acid herbicides, though not chemical (lemon juice and vinegar), are all total herbicides, meaning they kill all green plants, not just broadleaf ones. If you spray them on your lawn, the grasses will also die, leaving you with a dead lawn.
There is a herbicide for lawns, corn gluten, but it doesn’t kill living dandelions. Its role is to prevent the germination of plants, including dandelions. So you can prevent them, but it’s not so easy to get rid of them.
Removal: A Partial Solution
You can always pull up dandelions by hand, but if that’s all you do, the results will be mixed. You’ve just left dozens of holes in the lawn where new dandelions can sprout! So, to complete the removal, always top-dress (lay a thin layer of soil) and reseed with grass seed. This way, grasses will grow in the holes, not dandelions.
Insects in the Lawn
Chinch bug and webworms in turf can be treated fairly easily with organic insecticides (insecticidal soap, etc.). Better still, sow low-maintenance turf and you won’t have any problems with chinch bugs and webworms (this grass contains endophytes, fungi that are beneficial to grasses but make their leaves indigestible). But what about grubs? These plump worms live deep down, beyond the reach of insecticides… and they eat grass roots, where endophytes are absent. They can be treated with nematodes (follow the instructions precisely) or with a product containing the bacterium Bacillus thuringiensis subsp. galleriae.
Insects on Plants
Again, the usual biological insecticides (insecticidal soap, etc.) are quite effective.
Insects Inside of Plants
There are no systemic biological insecticides that penetrate the plant to make it toxic to insects in all its parts. This means that borers and miners, which live inside the plant’s tissues, will not be easy to control. You can always tear off leaves affected by leafminers, but when a stem or trunk is affected by borer insects, like the bronze birch borer, what can you do? The best you can do is maintain the tree by watering and fertilizing it as needed to increase its vitality, but this is most effective when the tree is young and still free of infestation. Old, infested trees are likely to die.
Should we cry about it? Not really. Birches are naturally short-lived trees, and the role of birch borer is to put an end to weak birches. If you must plant a birch, however, it’s best to choose a species that is naturally resistant, such as black birch (Betula nigra) and yellow birch (B. alleghaniensis), and above all to avoid European birch (B. pendula).
A Solution for the Laidback
Get rid of problem plants! This applies to lawns too, for those who can’t tolerate weeds. If a plant regularly falls prey to disease or insects, it’s best to replace it with a more suitable alternative. With the wide choice of plants available, there’s no reason to tolerate plants that cause trouble year after year. In short, if a plant doesn’t suit you, compost it and find another that will better meet your expectations.
Larry Hodgson published thousands of articles and 65 books over the course of his career, in both French and English. His son, Mathieu, has made it his mission to make his father’s writings accessible to the public. This article on pesticides was originally published in Le Soleil on June 10, 2006.
quick question You mentioned the birch is a short lived tree Can you give me an idea how long? Our 2 birches are about 10 yr old. They are doing well with new growth, but dropping a lot of yellow leaves. We lived in Nashville Thank you. Love the blog.
Oh, I loathed my former lawn! I likely mentioned it before. It was at my home in town, where neighbors expected reasonably presentable lawns in front, even where there were no children or dogs to enjoy them. I sort of maintained it to be reasonably presentable from the street, but on closer inspection, it was nothing to brag about. To me, it was such a waste of space and, here in California, a major waste of water. I miss the neighborhood very much, but not the front lawn!
My dilemna is that I have two plum trees and three apricot trees, and for some reason the plum curculio is very prevalent here in central NJ, enough so that virtually every fruit this year has been bitten, which means they will drop to the ground long before ripening. The pesticide recommended to control the curculio are not allowed to the home gardner, and they are pretty nasty chemicals. My only hope is to use an available pyrethroid chemical – gamma cyhalothrin – contained in Spectracide’s Triazicide formulation. The label gives a dosage for the curculio, but I’m not sure if it’s at all effective. We’ll get zilch fruit this year, and I’m willing to experiment with Triazicide for another couple years. If I don’t get decent results, I’ll be forced to cut the trees down. Currently, I’m using a spray that combines Triazicide, Surround (kaolin clay), and diatomaceous earth.
For those who don’t know, a pyrethroid is a synthesized molecule that’s similar to a pyrethrin, which are organic pesticides derived from the plant Chrysanthemum. The pyrethroids are not classified as organic, but they are still relatively of low toxicity to humans. There’s no evidence for cancer. But they can still be destructive to bees and other harmless/helpful insects. I’m thus willing to use pyrethroids, with care, if they’re effective.