10 yrs. ago on NPR i heard an angry woman scientist from India talking about how the "white man" had come and taken the Neem tree properties away to patent, and how it was no-different than what they'd always done to the indigenous Am. "Indian" people: steal all they could.
So i never bought Neem; instead used a Native SW product: Red-Chile powder (HOT variety, but use it with plastic gloves and a face-mask!) i mix a tiny bit w water and a few drops of soap. This is something sold most everywhere and you can also buy it directly from the SW 1st- Nations' people. i use it on flowering & non fl. plants, but i wouldn't use it on edible green vegetables for obvious reasons, ha-ha!