Are there neonicotinoids in dahlia flower bulbs? I am starting to keep bees and I am concerned about the pesticides in my bulbs. Can you help me?
It's common practice for professional growers to use pesticides when cultivating flower bulbs. Greenpeace investigated the use of pesticides in commercially sold flowering plants in Europe and found that:
Only 2% of the samples contained no detectable residues. Insecticides regarded as of particular toxicological significance to bees were found frequently. In 68 of the 86 tested ornamental plants (79% of the samples) bee-harming pesticides were detected. [source: Greenpeace study held in 2014]
In september 2013 a ban was placed in Europe on the use of 3 types of neonicotinoids for certain agricultural use, but due to loopholes in the legislation many plants still contain the banned neonics. According to the same Greenpeace study I mentioned above
The three neonicotinoid pesticides ... were found in almost half of the samples: 43% of the samples contained Imidacloprid, 8% Thiamethoxam and Clothianidin was found in 7% of the total, partly in high concentrations.
So to conclude, if the bulbs aren't labelled as being organic it's likely that they contain pesticides. I suspect that the only way to know for sure is to get the bulbs tested in a laboratory. Alternatively you can try to find out where exactly the bulbs came from and contact the grower for more information.