As I brushed against the beautiful blue flowering Salvia guaranitica I saw a burst of movement out of the corner of my eye. I would have loved to ignore it and just keep on pruning, but I’m an old and wily gardener, and I know it’s best to investigate anything unusual I see in my garden immediately. Sure enough, when I brushed the Salvia again, there was a burst of action. Tiny white insects swarmed for a moment and then settled back onto the undersides of the leaves. Oh no. Whitefly.