Lavender Plants

My lavender plants have developed a white foam on the stem at the joints of the plant. Does anyone know what it is?

 

I'm not even sure if they occur there but a type of spittle bug, perhaps?

 

Very likely - the spittlebugs love the lavender here at the garden.

 

Thank you for your reply -- This is exactly what I have on my plants. Now I need to find out what kills them.

 

The variety(ies) that occur here do negligible harm to plants, and are only visible for a short season...
But if they seem unbearably unsightly, they can be removed with a jet from the garden hose.

 

Thank you very much for the information on how to deal with these pests.