When we think of natural insecticides, botanical resources first come to mind. Plants such as the Nicotine, Derris, Pyrethrum, Neem and Caffeine are popular natural insecticides. Boric acid is another popular natural insecticide, though not botanical. Most homemade natural insecticides come from the botanical plants listed above. It is rarely heard of other natural insecticides popularly mentioned as these. However, they are other alternatives of natural insecticides to those listed here already.
Before some of the botanical resources were discovered, farmers and gardeners discovered soap as a natural insecticide. Whale soap and fish oil soaps were used to combat insects. It is well known today that dishwashing soap when mixed with plenty of water, works as a powerful natural insecticide. Using soap as a natural insecticide is not as powerful as the botanical resources or the boric acid. So, repeated applications on plants are much more necessary for desired results. This creates a problem. More applications of soap on plants may cause some damage to plants. This is a catch 22. The best soap to use should be soap that contains coconut oil.
Other forms of natural insecticides can include mixtures of onions, garlic and peppers. Incidentally, this will probably work as an effective repellent for humans – joke intended. This natural insecticide intervention will also need repeated application on plants. Soybean oil from the seeds of certain plants is also effective. Soybean is native to Japan or China and is used in animal feed. Sesame oil from sesame seeds used popularly on breads can also be an effective natural insecticide. Sabadilla is also a botanical insecticides but not as common or popular as those mentioned earlier. This particular natural insecticide attacks the stomach of insects with poison. It also poisons insects by contact.
Other oils include Canola, Which irritates insects by coating the leaves and Catnip, interestingly a stronger repellent against mosquitoes then Deet. Cedarwood and Citronella oils are also good natural insecticides. Cottonseed is actually the best vegetable oil that can be used as a natural insecticide. Garlic oil has also proven effective. However, garlic oil has also killed innocent insects. It kills insects almost immediately. Finally, Herbal and JoJoba oils can be used as natural insecticides. Herbal oils especially seem to reduce the number of eggs and feeding damage by certain insects. As you can imagine Herbal oils come from all kinds of teas such as White Clover, Anise, Sage, Tea Tree and other teas. The interesting fact with JoJoba oils is that it creates a natural wall between the insect and the leaf of the plant.
There also mineral based natural insecticides. Sulfur can be used in many ways to protect vegetables such as legumes, root vegetables and green beans. It can also be used to protect fruit such as fresh raisins and natural starch but sweet fruits. For those using these homemade natural insecticides, using it one time and expecting immediate results, is foolish.
Like other natural insecticides, is wise to use a mask in order to avoid eye irritation.