By Bonnie L. Grant
Finding safe, non-toxic pesticides for the garden that actually work can be a challenge. We all want to protect the environment, our families and our food, but most non-chemical products available have limited effectiveness. Neem oil insecticide is everything a gardener could want. What is neem oil? It can safely be used on food, leaves no dangerous residue in the soil and effectively reduces or kills pests, as well as prevents powdery mildew on plants.
What is Neem Oil?
Neem oil comes from the tree Azadirachta indica, a South Asian and Indian plant common as an ornamental shade tree. It has many traditional uses outside of the insecticidal traits. For centuries, the seeds have been used in wax, oil and soap preparations. It is currently an ingredient in many organic cosmetic products too.
Neem oil can be extracted from most parts of the tree, but the seeds hold the highest concentration of the insecticidal compound. The effective compound is Azadirachin and it is found in highest amounts in the seeds. There are numerous neem oil uses, but gardeners hail it for its anti-fungal and pesticide properties.
Neem Oil Uses in the Garden
Neem oil foliar spray has been shown to be most useful when applied to young plant growth. The oil has a half life of 3 to 22 days in soil but only 45 minutes to 4 days in water. It is nearly non-toxic to birds, fish, bees and wildlife, and studies have shown no cancer or other disease causing results from its use. This makes neem oil very safe to use if applied properly.
Neem oil insecticide
Neem oil insecticide works as a systemic in many plants when applied as a soil drench. Once the product is in the plant’s vascular system, insects intake it during feeding. The compound causes insects to reduce or cease feeding, can prevent larvae from maturing, reduces or interrupts mating behavior and, in some cases, the oil coats the breathing holes of insects and kills them.
It is a useful repellent for mites and used to manage over 200 other species of chewing or sucking insects according to product information, including:
Neem oil fungicide
Neem oil fungicide is useful against fungi, mildews and rusts when applied in a 1 % solution. It is also deemed helpful for other kinds of issues such as:
How to Apply Neem Oil Foliar Spray
Some plants can be killed by neem oil, especially if it is applied heavily. Before spraying a an entire plant, test a small area on the plant and wait 24 hours to check to see if the leaf has any damage. If there is no damage, then the plant will not be harmed by the neem oil.
Apply neem oil only in indirect light or in the evening to avoid the product burning foliage and allow the preparation to seep into the plant. Also, do not use neem oil in extreme temperatures, either too hot or too cold. Avoid application to plants that are stressed due to drought or over watering.
Using neem oil insecticide about once a week will help kill pests and fungal issues as bay. Apply as you would other oil-based sprays, making sure the leaves are completely coated, especially where the pest or fungal problem is the worst.
Is Neem Oil Safe?
The packaging should give information on dosage. The highest concentration currently on the market is 3%. So is neem oil safe? When used properly, it is non-toxic. Never drink the stuff and be sensible if you are pregnant or trying to get pregnant. Out of all the neem oil uses, the one that is being studied is its ability to block contraception.
The EPA says the product is generally recognized as safe, so any residual amount left on food is acceptable; however, always wash your produce in clean, potable water before consumption.
There has been concern about the use of neem oil and bees. Most studies specify that if neem oil is used inappropriately, and in massive quantities, it can cause harm to small hives, but has no effect on medium to large hives. Additionally, since neem oil insecticide does not target bugs that do not chew on leaves, most beneficial insects, like butterflies and ladybugs, are considered safe.