What can I do about Rosemary Leaf Beetles?
This is copied from the UK Royal Horticultural Society – RHS site: ‘Rosemary beetle can be controlled either with insecticides or hand picking of adults and larvae. If pesticides are used then these are best applied in late summer to early autumn or in the spring, when the beetles and larvae are active on the plants. Suitable insecticides that can be used include bifenthrin, thiocloprid or imidacloprid. Insecticides should not be used while plants are in flower because of the danger to bees. Only the ready-to-use formulation of thiocloprid (Provado Ultimate Bug Killer Ready to Use) is approved for use on edible herbs.’ They’re becoming a growing nuisance in the UK, after spreading in from the continent. I don’t have them, and my Rosemary plants are fine. I don’t know whether diluted washing up liquid will work, or other soap based insecticides. These are not poisonous killers, and just kill on contact -always beware of beneficial insects, including ladybirds, bees and lacewings though.
