Neem oil foliar spray has been shown to be most useful when applied to young plant growth. The oil has a half-life of three to 15 days in soil, but only 45 minutes to four 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. This means it is absorbed by the plant and distributed throughout the tissue. 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 percent 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 on the 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 should not be harmed by the neem oil.
Apply neem oil only in indirect light or in the evening to avoid foliage burning and to allow the treatment 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 overwatering.
Using neem oil insecticide about once a week will help kill pests and keep fungal issues at 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.