Q.Grevillias and White Oil
I have been advised to use white oil insecticide on my Grevillias for black scale and other pests. It won’t harm the bush, will it?

Certified GKH Gardening Expert
Just make sure that you do not use it in bright light. White oil can occasionally burn a plant on a very sunny day. You may also want to look into neem oil. It is effective on these pests and safe for people and pets and will not intensify sunlight. Here is more info: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm