James Kirkham Ramsbottom

By April 1917 Ramsbottom was able to prove the disease was caused by an infestation of the Ditylenchus dipsaci nematode and developed a treatment involving dipping affected bulbs in hot water.

[1] He gained first place in the Royal Horticultural Society's (RHS) diploma examination and won a gold medal for scholarship.

[7] By 1916 attitudes had relaxed a little, and it was suggested that the society study the disease at a March meeting of the RHS Narcissus and Tulip Committee.

He noted that while many contained fungal infections, all of the bulbs he checked showed the presence of the nematode Ditylenchus dipsaci, first discovered by Friedrich Adalbert Maximilian Kuhn in 1858.

[4] Ramsbottom demonstrated that the mites and flies present were not the initial pathogen but were attracted by rotting caused by the action of the nematode.

[7] Having found the cause, Ramsbottom trialled different treatments to determine their effectiveness against the nematode and impact on the viability of the bulb.

[5][1] Ramsbottom went on to prove the effectiveness of his treatment in commercial stocks in 1919, in the process probably saving many early varieties, such as the "Carlton".

[7][10][11] Ditylenchus dipsaci is now known as the stem and bulb nematode because of its means of infection, proven by Ramsbottom, and it remains the most significant pest in daffodils.

[4][12] Ramsbottom's treatment for the infection remains the basis of modern nematode control in daffodils, though by the 1960s, a slightly higher temperature of 114–115 °F (46–46 °C) was preferred.

[6] After studying the disease, Ramsbottom spent five years experimenting with and perfecting apparatus for the commercial treatment of bulbs and worked closely with many growers.

[1] Ramsbottom's study on the stem and bulb nematode led to him becoming famous in horticultural circles in the United States.