Got some Imidacloprid to treat mealy bug, scale etc. on plants - I have one customer with quite tall hibiscus that they use as a privacy screen, it's been hit with mealy bug on the new growth after a recent trim. The owner has been spraying neem, but I don't know if she will get full coverage. Was reading through the Imidacloprid booklet and saw that stem injection is a suggested treatment for Pandanus - drill 1mm holes into the trunk and put the pesticide in.

Has anyone done this in the past? Would it also work for hibiscus?

It's either that, Confidor tablets, or I'll have to wear a hazmat suit to spray the entire plant (at least 4m tall).