I have Daphne plant in a tub and I notice that when I water it white sort of sawdust comes to the surface. Looks to me as though the soil has been invaded by something and will kill the plant. Can you advise what it might be?

Hi, it sounds like you have a type of aphid or weevil in your soil. If your container isn’t too big, suggest removing your Daphne from the container and rinsing off as much of the soil as possible and replanting into fresh new mix. Alternatively, look for an insect spray in the garden centre and spray to control it.