Four years ago I bought about ...£200 worth of mixed daffodil bulbs for my garden. The first year display was stunning but the second year there were only about half in flower. I dug up a few bulbs and noticed that the centres had been eaten and there was a grub inside which I took to be narcissus fly. Last year the show was very disappointing and this year there is only one solitary flower, however there are quite a lot of leaves. I have done some research on this and concluded that there is no cure for this pest but will this narcissus fly stay in the garden and infect any new bulbs I plant in the future? At the moment it's rather expensive to have a show that only lasts about one year.
Regards
I can't say for sure, but the bulbs might have already been infected when you bought them.
Interesting thing about these bulb flies is that the bulb will often survive the attack. It will take a few years, but it can recuperate and begin to produce flowers again.
I found 2 interesting articles about them that might help you understand them better. One point I found of particular interest was that if you remove the grub from the bulb, you should leave the frass behind, as it has antibiotic properties for the bulbs. Here are links to the articles:
https://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=657
https://www.pacificbulbsociety.org/pbswiki/index.php/NarcissusBulbFly
Interesting thing about these bulb flies is that the bulb will often survive the attack. It will take a few years, but it can recuperate and begin to produce flowers again.
I found 2 interesting articles about them that might help you understand them better. One point I found of particular interest was that if you remove the grub from the bulb, you should leave the frass behind, as it has antibiotic properties for the bulbs. Here are links to the articles:
https://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=657
https://www.pacificbulbsociety.org/pbswiki/index.php/NarcissusBulbFly