They are whiteflies, a very common and pesky pest!

Thank you! I just read up on them and they sound incredibly annoying. Do you know what's the best chemical-free method of getting rid of them?

I'd be hesitant to suggest my usual remedies, since the foliage of lemon balm is so hairy. That can cause a problem, even with the (so called) organic methods of control.

But I'll bet that someone else here has some hands on experience to share with you.

Whiteflies are supposed to be attracted to yellow. IÂve heard you can get either yellow poster paper or a packet of yellow paper at a place like Office Depot, smear it with Vaseline, tape/attach it somehow to a nearby post or fence or prop it up with sticks, & they will get stuck in the vaseline. Sounds sad to me but they are a problem. Note: pest strips are yellow for the same reason I think.

I heard this from a presenter at a garden workshop but haven't had an infestation yet to try it out. If you find something that works, please update us here. Thanks!

Even though the white flies are annoying they don't actually do too much damage to your plants. When you use the balm you can just wash them off the leaves. Alternatively, if the plant has a real infestation lemon balm is so tough you could just cut the whole thing down to the ground and get rid of the affected foliage. If your climate is dry keep it watered and it will grow back lush and green. If you have sufficient rain just watch and wait. In fact lemon balm needs frequent haircuts anyway or it gets ratty.

Whitefly traps (yellow sticky traps) work well. Place a couple on stacks in the area where your lemon balm is and they'll soon be covered with whiteflys.

Here is a link that might be useful: WhiteFly traps

Thank you all for your advice. In my panic, I went out and bought a pesticide, eep! I've also cut off most the foliage. I'll make sure to use sticky traps next time and keep you updated on how that goes. Thanks again!

Maybe whiteflies don't become much of a pest in the UK, but they surely can here! A serious population can severely weaken an infested plant...and that darned black sooty mold!

Though the yellow sticky traps work great for this pest, they can also entrap things you may not want to catch. When I lived in SC, the little green anoles (lizard) became victims when I placed some of the sticky traps in one of my greenhouses. When I saw that, we collected all of the traps and threw them away.

That might not be an issue where you live, greenie. Good luck with the pests.

rhizo_1 whitefly are a serious problem in greenhouses here but are just a bit unsightly outdoors. Maybe we get plenty of rain and that keeps them on the hop. Sticky traps are used in greenhouses but rarely outside. I would still recommend cutting the balm back as it gets messy even without whitefly.

I think you're right, flora. Your cloudy, rainy climate just may help keep whitefly a bit under control in the outside environment. And I'm all for cutting the lemon balm way back!