Cause Twenty-one viruses are known to infect daffodil. Two commonly observed are narcissus yellow stripe virus (NYSV) and narcissus white streak virus (NWSV). Both are potyviruses and, after more research, may be found to be the same virus. Aphids are a natural vector for these viruses but spread is slow. These viruses can also be spread by alternately handling healthy and infected plants during flower packing and other operations. They are not seedborne. Other viruses common in the PNW and possible on daffodil include cucumber mosaic virus and tomato spotted wilt virus.
Utah reports daffodils infected with narcissus latent virus, narcissus late season yellows virus, and narcissus mosaic virus.
Symptoms NYSV-infected plants are characterized by light-green, grayish-green, or dull to bright-yellow stripes or mottles mostly confined to the upper two-thirds of the leaf. The surface of the discolored area is most often roughened near veins and may have a peculiar twist. White streaks or blotches may appear on flowers, which are reduced in size. The cultivar Magnificence develops only green stripes.
Narcissus White Streak symptoms appear about flowering time (after temperatures exceed 64°F) on leaves and flower stems as narrow, dark green to purple streaks. Streaks later become white, yellowish white, or gray and may coalesce. They soon become necrotic and sunken, and the leaves die. Plants decline and produce smaller-than-normal bulbs.
Frost injury, water logging, and herbicide damage may be confused with virus diseases. However, virus-diseased plants will usually be scattered, while plants without virus problems are in a more uniform area.
Cultural control
- Remove diseased plant.
- Plant foundation stocks as far as possible from newly purchased stocks or commercial fields.
- Purchase and plant virus-tested (and found to be free of known viruses) material.
- Plant only the largest bulbs.
- Control aphid vectors. See the PNW Insect Management Handbook for details.
Reference Agindotan, B., Nischwitz, C., Galvez, M. E., Compton, T., Nunziata, S., Rivera, Y., Mavrodieva, V. and Nakhla, M. K. 2023. First Report of narcissus late season yellows virus, narcissus latent virus, and narcissus mosaic virus in daffodil (Narcissus pseudonarcissus) in the United States. Plant Disease, 107:2564.
Hanks, G.R. and Chastagner, G.A. 2018. Diseases of Daffodil (Narcissus). In McGovern, R.J. and Elmer, W.H. (eds.) Handbook of Florists' Crops Diseases. Springer Int.