Street whose nursery is based in Somerset said it was likely the fungus could be worse this spring thanks to the large amount of rainfall last summer and autumn.
"With the continual rain over the summer, the snowdrops didn't have a nice dry rest - a lot of them were under water," he said.
He added: "The increasing number of plant exchanges and trade in snowdrops by enthusiasts mean that the disease is being spread around far more than in the past, so it needs to be more widely publicised."
The disease is a problem for collectors who buy large numbers of snowdrops and plant them in them close together. It is caused by a fungus, Stagonospora curtisii which affects bulbs such as daffodils, hippeastrum, Crinum, nerine, Sternbergia and Galanthus.