Here is my homemade organics-based formula for getting rid of things like aphids, thrips and mealybugs on potted or patio pots.
WARNING: This formula is a work in progress. I'm sure there are some plants it won't work well on. In fact, it might even burn the leaves of some tropical plants. But, so far, the spray has killed no plant, and, in almost all cases, the bugs have been eliminated.
In a one-quart spray bottle, mix ...
- 1 tablespoon of neem oil
- ¼ to ½ cup of rubbing alcohol (use up to ½ cup when dealing with mealybugs)
- 3-4 drops of citrus oil (d-limonine)
- 5-6 drops of dish soap
Then fill the rest with water.
I started using a version of this spray about three years ago, when my son reached walking age. He loved going out on the backyard patio and, like any child, was just inquisitive enough to pick off any flower or leaf within reach. So, I figured it was time to start using only organic products on the patio.
I knew citrus oils would kill insects, but at the rates I tried, I burned many hibiscus leaves and potted flowers like New Guinea impatiens ... even petunias.
That is how the above formula evolved. I look at it as the best of many organic worlds.
We know citrus oil (d-limonine) works on anything, but at what rate will it cause a phytotoxic burn?
We know rubbing alcohol is perfect for mealybugs, but usually it has to be directly applied.
And we know neem oil is not only a natural insecticide, but a fungal protection agent, too.
And finally, we all know that most waters in Southeast Texas are hard, and by adding a bit of dish soap we create a surfactancy that will allow our homemade spray to actually stick to things.
Try it, and let me know what you think. I especially need to know on what plants it has a phytotoxic effect.
Good luck!