Google tells me: Usually pesticides make no difference between pests and beneficial insects. But neem oil is different.... neem oil is not really a knock down, kill-on-contact insecticide like the chemical poisons. Neem must be ingested (eaten by the bugs) to be effective. If bugs don't eat leaves they don't get hurt. Simple. In reality it is a little bit more complicated than that, but the fact remains that neem oil is impressive: it really does hurt bad bugs while sparing the good bugs.
Don't use neem outside. It's too easy to cause phototoxicity with it in my experience. JMS Stylets oil will serve you better. Get a gallon or two and you'll have it on hand whenever needed.
First the no-no’s: Do not use neem oil soap on drought stressed plants. It should not be used on new transplants, and recently rooted cuttings. Because of potential phototoxic problems it is wise not to spray neem oil soap on plants while they are exposed to full sun. Use it early in the morning, better in the evening hours. Avoid using neem oil soap with the air temperature is much above 85F.
Researchers have looked at it and found that neem oil is non toxic for example to spiders, butterflies and to insects that pollinate plants. Scientists looked especially at how neem oil affects honey bees, since bees do eat plant matter, the pollen.
That's why reasearchers studied what happens if flowers get sprayed with neem oil.
And what they found is very reassuring. To see any effect the scientists had to use very high concentrations of neem. They used a lot more than you would ever use for pest control.
Only if they constantly hit the flowers with a very concentrated neem oil spray did they see an effect, and only in some small hives (medium sized and larger hives were still unaffected.)
What happens is that the bees carry contaminated pollen back to the hive and feed it to the brood. In the small hives some of the new bees could not emerge from their cells (Schmutterer and Holst, 1987).
Weekly use of a neem oil spray at a normal concentration (0.5% - 2%) will not hurt honey bees at all.
You can also rest assured that while neem hurts aphids, whiteflys and the like, it does not harm ladybugs and other predators that eat the aphids, or the tiny wasps that are parasites on many pests.
I think keeping a clean room and monitoring it is a better idea. If something comes along then attack. If you like neem then use it(I think its crap) that way your plant will be like a fresh virgin and have no tolerance built up. Easier to knock down insect population that way.
The only thing I use 7/24 is a noseum net around my container to keep my roots protected. Suerte JK
That's great for inside. This cat's asking about outside. :) I've found what looks to be a good quality bug netting that I plan on setting up for my OD area, just don't know when I'll be able to get it set up.
You can also rest assured that while neem hurts aphids, whiteflys and the like, it does not harm ladybugs and other predators that eat the aphids, or the tiny wasps that are parasites on many pests.
I am always suspicious of terms like "researchers" because the folks who paid them to research usually get what they want. In this case, though, because neem oil is a commodity & thus no one is making serious money... I just a little leery, instead of dubious.