Bulbs: Agapanthus borers, 1 by ardesia

ardesia wrote:
Recently I dug up a 4' clump of Agapanthus. They had not performed well for several years and I thought a change of location would help. When I got them out I found they were infested with what I am pretty sure is borers.

There is another clump of a different variety (not sure of it's name but it is a smaller plant with deep blue flowers) nearby that is still healthy and I was wondering if I should treat them with something to prevent or kill any more borers. Not much for using chemicals but I am open to any suggestions.

Thanks.