Avoid spraying hairy-leaved plants, which hold oil too long.

When that tactic failed, he sprayed plants with a pepper solution - also to no avail.

Peronospera can be treated by spraying plants with copper sulphate.

You must follow the guidelines for spraying plants with herbicide and digging up plants.

See the pages in this guide on spraying invasive plants with herbicide and digging up invasive plants.

Isn't this more fun that spraying plants with pesticides?

At the first sign of infection, begin spraying plants weekly.

Care must be used with such an application to avoid spraying non-target plants.

If too much of a chemical has been mixed, the best way to dispose of spray is to continue spraying plants until the container is empty.

See the page in this guide on spraying invasive plants with herbicides.