As I have said previously, all good things in life must be used in moderation, or they are no longer good!
On the other side of the equation, neem oil has been found to be highly safe to bees. In fact, using neem oil as advised helps to cure Nosemosis and is widely used in the bee keeping industry to as a botanical method to treat varroa and tracheal mite problems of bees, which can decimate an entire colony at once.
Because neem products are used for human consumption and medication, exposure to neem in the process of treating plants with neem oil poses no threat to humans or other higher animals. Moreover, neem is not harmful to beneficial insects, affecting only those insects feeding
on plants treated with neem. Since most predator insects do not also feed on plants, they are not harmed by the presence of neem. Neem biodegrades in a matter of weeks when exposed to sunlight or in soil.
Neem-based products have been extensively tested and are as effective insecticides in commercial greenhouses. The Neem seed has been the subject of extensive testing throughout the world since World War II. Neem has been tested at major universities throughout the U.S. and Canada since 1982.
In EPA testing, establishment of an LD-50 proved impossible as azadirachtin, present in neem oil, was asymptomatic at all levels tested. Accordingly, there are no reentry or residual restrictions associated with the use of neem oil.
So, as with everything else, weigh the pros and cons of any product before you use it!!!