Recipe for Homemade Pesticides for Organic Gardens
You can buy all sorts of organic oils and soap sprays, most at a reasonably high cost. Years ago, I was given this formulation by Cathy Crowley of Crowley's Nursery outside of Sarasota, FL for a homemade natural insecticide and have used it ever since. With the exception of using Spinosadtm on my fire ants, I've never had to use anything else.
- 1/3 cup of Murphy's Oil Soap (use the name brand, because the generics may have harsh soaps that can burn your plants)
Spray this mixture only in the early morning or in the evening, when it's cooler. If it's sprayed in the heat of the day, it will burn the plants.
This insecticide is effective against aphids, spider mites, leaf miners, scale, and some chewing insects. It is also effective against fungal diseases such as rust, black spot on roses, and powdery mildew.
Other Natural Insecticides
Fungus cannot live in the alkaline environment created by the baking soda. The oil and soap smothers most insects, or interferes with their breathing so that they die.
Milk is also used for powdery mildew, botrytis, and black spot. Whole 4% milk is mixed with water and sprayed on plants. A weak solution is 1:9 parts milk to water, while a strong solution is 1:1. A stronger solution may work for a week, but a weaker solution may only work for 3 days. You will have to experiment to see what works bets for you.
While milk controls black spot and rust on roses, and keeps it from spreading to other plants, it is not a cure.
Organic gardening is the wave of the future. Neem Oil and Spinosadtm are only the beginning. There is research being done every day to find more and better natural pesticides for organic gardening. In the meantime, I hope that one of the suggestions above will suit your needs.