Green pesticides are pest control solutions that are less harmful than chemical pesticides and that can be just as effective.
The greenest solution to pest problems is natural control: letting bugs eat bugs or plants develop resistance. Ladybugs, for instance, are known as aphids ogres. It is possible to buy lady bugs so you can release them in your garden as a team of aphid-busters. But they may decide to move to your neighbor’s yard and they may not be fast enough to save your plants. They may even pose problems of their own. Boosting your plants’ immune system is also a good idea that may not be appropriate in an emergency situation.
Bear in mind that green pesticides are still pesticides. The ingredients they contain can be harmful too, for your plants as well as for yourself. They should be handled with caution and should not be overused. Sulfur, for instance, is a natural pesticide and fungicide that has been used for ages. But the sulfur solution you spray on the leaves of your rose bushes to get rid of those dark spots is not meant to be inhaled. So you should use caution when using these pesticides. Wear gloves, glasses and long sleeves so as to prevent any contact with your skin and eyes. Don’t spray plants on windy days and wear a mask when spraying large plants, as the mixture is likely to saturate the air around you.
The easy way: brand name products
If you don’t want to bother making your own green pesticides, there are a few brand name products that can be used to effectively control pests. Soap has been used for many years and many people use dish-washing liquid, but one has to be very careful with solutions such as dish-washing liquids. They can be quite harsh and many of the contain ingredients that should not be used on plants, such as germicides. The good thing about soap is that it tends to stick to foliage and thus remain effective for a longer period (at least until it rains sufficiently to wash it off).
It is common knowledge that insects tend to be repelled by plants such as basil, peppermint and chives. Solutions containing essential oils from such plants have the same effect on a large variety of bugs, and the nice thing about it is that bugs can’t seem to develop resistance to them. We recommend a visit to Natural Living Ideas for information on this subject.
So instead of making your own somewhat effective but maybe harmful pesticide using your own dish-washing liquid, you are much better off buying a commercial product that combines the right soap with the right essential oils in the right concentration to form an effective solution against bugs.
The Woodstream corporation markets such a product under the name ‘Safer® Brand Insect Killing Soap’. Their solution is recognized as organic by the Organic Materials Review Institute. It can be purchased in concentrated form and diluted whenever needed.
When using such products, you must spray every surface where bugs are likely to hide. This is not a systemic product (systemic doesn’t usually rhyme with organic), it has to come in direct contact with both sides of all the leaves and with the stems. And since a hard rain will wash most of it away, it must be reapplied whenever necessary.
Homemade green pesticides
Making your own pesticides can be quite easy and homemade pesticides can be just as safe and just as effective their commercial counterparts. Just make sure that you follow each recipe very carefully. If the recipe says that you should dilute one cup of a given mixture in four gallons of water, don’t use two cups, thinking that it will get rid of the bugs faster, as it may get rid of the plant itself. Plus you don’t want to kill or repel other useful organisms living in your garden.
And when making pesticides, you should also wear gloves, glasses and long sleeves so as to prevent any contact with your skin and eyes.
You should not mix different pesticides. If possible, use different containers and bottles so as to make sure that different solutions don’t interact.
You should also be aware of the fact that most of these solutions do not keep. So you should only prepare as much as you need.
And don’t use any green pesticide before testing it first. Spray the solution on a few leaves and wait 24 hours to see how the plant reacts. If the leaves you sprayed appear to be discolored or softer than usual, wait a few days and try using a different pesticide.
Adding a few drops of dish-washing liquid to the following pesticides will help them stick to the foliage and thus remain active longer.
Neem oil is a natural insect repellent and insecticide that is effective on hundreds of insect pests. It has two big advantages: insect pests cannot develop resistance to it, but most of all, it is not harmful to those insects which you do want to keep in your garden, such as ladybugs. It also has very low toxicity on animals and humans. Neem oil is extracted from neem seeds and can be easily purchased in most countries.
Mix one once of neem oil with a gallon of water and one teaspoon of dish-washing liquid. Spray on plants and trees.
Nettle, stinging nettle or common nettle (urtica dioica) can easily be found in shaded woods, where the soil is rich, acidic and moist. There are many species of nettles. The Wikipedia page on nettles may help you identify the right plant. Search engines, such as Google, can also help.
Many people see this plant as a nuisance, due to its stinging leaves and stems. You can grow it on your yard, if you have a shaded, wet spot, but be aware that once it takes hold somewhere, it’s hard to eliminate. Be sure to wear gloves whenever you handle nettles.
Nettles slurry is good against mites and aphids as well as mildew and rust.
Coarsely chop 1.5 pounds of nettles and soak in 2 gallons of water. Let stand for 24 hours. Remove the leaves. To spray on the foliage, dilute one part of this solution in 20 parts of water. To use in the soil, use one part in five to ten parts of water.
This plant being quite invasive, it can easily be found near wooded areas and along trails. Its bright yellow flowers make it easy to spot. The Wikipedia page on tansy may help you identify the right plant.
Tansy slurry is good against aphids, caterpillars, flea beetles, white flies and weevils.
Soak one pound of tansy in 2 gallons of water. Let stand for 24 hours, than boil for 15 minutes. Remove the leaves and leave to cool. Spray on plants.
Horsetail grows in poor, sandy soils, and can often be found along streams and marshes, in wet clay soils.
There are many horsetail species. The Wikipedia page on horsetail may help you identify the right plant. Search engines, such as Google, can also help.
Horsetail slurry is an effective green pesticide against rust, Botryotinia and mildew, but it is also effective as a tonic.
Soak two pounds of finely chopped horsetail in 2 gallons of water, than boil for 30 minutes. Let stand for 12 hours and drain. Dilute one part in five parts of water. Spray on plants.
Rhubarb stalks are often used in the preparation of jams and pies, but rhubarb leaves make a great green pesticide. Boil them to easily make a pesticide that will help you get rid of aphids.
Boil 2 gallons of water and add 2.5 pounds of fresh rhubarb leaves. Remove from heat and let stand for 24 hours. Remove the leaves and filter. Spray on plants.
For general information, visit our green landscaping page.