Narcissus Viruses.

[Giles]

I wondered how carefully folk inspected their plants for signs of possible virus infection and how stringent they were about discarding bulbs that were possibly infected.
Every daffodil in my garden has slight yellow streaking in the foliage, and I was left doubtful if maintaining a virus free Narcissus collection was realistically achievable, especially if growing named forms/cultivars.

What approach do forumists take?
..discard all possibles?  ..discard only those with poor vigour/poor flowering?  ..give it a year, and see if symptoms persist?

[Matt T]

First, as all your plants are showing symptoms, I'd consider whether there is a cultural factor causing it. I'd try giving them all a bit of a feed/tonic and see if that resolves the streaking first. However, good cultivation practices can reduce the expression of viruses, which are still present and can be passed on by sap suckers. Once you've ruled that out and suspect a virus your course of action will depend on why you are growing them and how much you value them. If they are giving you a good floral display in the garden and you're not intending to be selling/sharing them then maybe you can keep them and enjoy them. If you're growing them for commercial purposes it would be better not to sell on such bulbs (although many commercial sources do so  ) If you are maintaining a diverse collection of rare and/or expensive plants, it may be best to dispose of any suspect looking plants (dustbin or burn, not compost heap).

[Giles]

Thank you for your thoughts, Matt.
My bulbs grow and flower nicely.
I had a rummage through the scientific literature and it seems that most commercially grown daffs are virused, even those that look normal.