IMO, so many people use Neem Oil and/or Neem Cake/Seed Meal thinking it contains significant levels of Azadirachtin. They do not, rather we are discussing three or more different "active ingredients":
So, ask yourself:
What pest/condition are you treating?
What active ingredient are you seeking...and is it included in the selected product?
Why would a gardener use horticultural oil (normally applied as a foliar spray) as a soil drench?
Are you using Neem Cake/Seed Meal or Neem Oil and foolishly believing they contain significant levels of Azadirachtin?
- Azadirachtin OPP Chemical Code: 121701 (CAS # 11141-17-6)--derived from Neem Oil and is found to be an insect growth regulator, interfering with the normal life cycle of insects, including feeding, molting, mating, and egg laying. It can be a feeding deterrent in some insects.
- Clarified Hydrophobic Extract of Neem Oil OPP Chemical Code: 25007 (CAS # 8002-65-1)--derived from Neem Seed and is the "left over" byproduct after Azadirachtin and other is extracted. The oil is known to be an insect repellant (unlike azadirachtin) is active against fungal diseases such as mildews and rusts.
- Neem Seed Meal/Cake--derived from Need Seed and is the "left over" byproduct after Neem Oil is extracted. Neem Cake is an excellent fertilizer rich in both macro and micro nutrients that also improves fertility and inhibits nitrification by soil bacteria.
Azadirachtin and Clarified Hydrophobic Extract of Neem Oil are derived from the natural oil found
in seeds of the neem tree, Azadirachta indica A.Juss, which is native to arid regions of India. The
ability of the oil to repel pests has been known for thousands of years; the oil also has been used
on skin and medicinally. When the natural neem oil is removed from the seeds and treated with
alcohol, virtually all of the azadirachtin and related substances separate from the oil itself. The
remaining oil - without the azadirachtin - is called Clarified Hydrophobic Extract of Neem Oil.
Azadirachtin acts in the following ways: It deters certain insects, such as locusts, from feeding
and it interferes with the normal life cycle of insects, including feeding, molting, mating, and egg
laying.
So, ask yourself:
What pest/condition are you treating?
What active ingredient are you seeking...and is it included in the selected product?
Why would a gardener use horticultural oil (normally applied as a foliar spray) as a soil drench?
Are you using Neem Cake/Seed Meal or Neem Oil and foolishly believing they contain significant levels of Azadirachtin?