Illegal Pesticide Use – Neem Oil – Ontario – Toronto Bonsai Society

Neem oil, a natural oil from the seed of the neem tree, usually comes in a 70% concentration.

It is used against powdery mildew, white flies and their eggs and the eggs of different species.

Neem oil sprayed on leaves deters feeding by leaf-chewing beetles and caterpillars.

It is also suggested that it affects the hormones many insects need to develop, killing them as

they attempt to molt or emerge from eggs. There is disagreement how effective neem oil is against

aphids and other sucking insects. Caution should be exercised when using neem oil, follow the

cautions mentioned above about horticultural oils. 


To make your own neem oil spray use 5 ml neem oil, 1-2 ml insecticidal soap or detergent and

1 liter of water. Mix water and soap, add oil slowly and mix well, keep agitating while spraying.

One batch of neem oil spray is good for 8 hours before it breaks down in the mixture.

Spray once a week. 


Nicotine, contained in tobacco, is a natural insect repellant which can be used against aphids,

white flies, leaf hoppers, thrips, and other sucking insects.

Take 2-3 cigarettes and soak them for a week in 2 liters of water, strain and add 1 liter of water.

Only water your trees with this mixture, and do not spray.