Unlike most chemical insecticides that kill by contact with the insect, neem oil works by disrupting the insects’ hormones, so they must ingest the neem oil to be affected. This means that it only affects insects that bite or chew, and is safe for bees and spiders (and, unfortunately, fruit flies), unless they become coated in the oil. As the neem oil affects the hormones, only small amounts are required for insecticide use (0.5–1% neem oil in a carrier). Read more here about how it works.Also a safety note that I need to add, neem oil does have contraceptive properties, and should be used with care by anyone who is pregnant or seeking to become pregnant. Unfortunately, at a time when you want to avoid chemicals the most, you might also want to avoid neem oil, I’ll leave you to use common sense in this regard.
The repellent action of neem oil is less well understood, but appears to work (I am living proof), although its effectiveness seems to depend on the type of mosquito (see here). As far as I can find out, slightly higher concentrations (up to 10%) of neem oil are effective as an insect repellent. I think this explains why beneficial insects are not affected or repelled by the low concentrations used to kill biting insects, however, higher concentrations work to repel all insects (because I don’t want to wait for them to bite me, get sick and then die!).
|citrus leaf scale removed and repelled by neem oil|
In the garden
Neem oil is effective against biting and chewing pests. Recently I have used a 5% concentration of oil in water and detergent to remove citrus leaf scale. I just sprayed on the neem oil and scrubbed the leaves with a toothbrush (this is my mini lemon and lime in pots, so they don't have many leaves). The good thing was that any insects that I missed in the physical removal would have also been affected long-term by the neem, and it repelled the ants that tend the scale insects.
We also had a mystery bug making holes in Pete’s hydroponic tomatoes. I sprayed all the formed tomatoes with the same mixture and the holes stopped. It was good to know that the spray would not affect pollinating insects, as there were plenty more flowers on the plant that still needed their attention. We just had to wash the film of neem oil off the tomatoes before we ate them, which was much nicer than washing off derris dust.
|here's that unhappy wet rooster again|
In the farmyard
Recently I shared with you my success using neem oil to remove mites and lice on the chickens. I can report that all chickens I have checked lately are free from external parasites. Having previously used toxic chemicals to treat the chickens, I am very pleased to find a more natural alternative. It is more pleasant to use and I don’t have to worry about not eating the eggs afterwards.
In the house
Over summer we were constantly battling ants in the kitchen. I had tried everything, chemical and non-chemical, short of calling in pest controllers. Finally I had a brainwave and sprayed all the benchtops with neem oil with the same mixture as above (I find this is a general purpose concentration). I had to repeat this over a week or so, and eventually the ants disappeared. I dont't know if this worked due to either the repellent effect or I have actually killed the nest, either way, they are gone and I am happy.
On the people
I have been using the neem-based insect repellent that I mentioned in the previous post, and its great, it really seems to work in most conditions, and although it does smell strong, its no worse than chemical insect repellent. I am thinking about making my own version with some added beeswax for a thicker mixture, as the oil does tend to leak out of bottles, although so far it has washed out of all the clothes I have split it on (there have been a few incidents).
|my gross nail fungus is completely gone after using neem oil|
The other application I have found is treating a nasty nail fungus. I had denied the problem for so long, that it had covered half my big toe nail before I did anything. After some research, I found out that neem oil was a treatment option, which I preferred to buying a medicated cream, so I covered my toe nail in pure neem oil every night for 6 weeks. I could clearly see the improvement after this time, and 6 months later the damaged nail has nearly grown out completely, leaving healthy nail behind (wow nails grow slowly!).
As you can imagine, a neem tree is very high on my list of herb trees to plant in our new garden. It is an amazingly useful and I keep finding more uses. Now anytime I have a problem with an insect I think of neem oil. What do you think? Have you used neem oil successfully?