Thousands of trees in France are felled and burnt every year in an attempt to prevent the transmission of spores.
The association says if the disease reaches London it could take three generations to replace the trees, and called on Defra to prevent “serious consequences” for the city’s air quality.
Defra said: “We take a vigorous approach to protecting trees and had the UK designated as an EU Protected Zone for this disease. Imports must be from disease free areas and importers must allow us to monitor the trade.”