Comparison of commercial elm cultivars and promising unreleased Dutch clones for resistance to Ophiostoma novo-ulmi

Elms, and especially Ulmus × hollandica have been dominant and very much appreciated trees in cities and rural landscape for centuries in the Netherlands. As a result of two Dutch Elm Disease (DED) epidemics in the 20th century these trees largely disappeared from the landscape. Despite the introduction of new cultivars with increased levels of DED-resistance, by the end of the 20th century the elm had disappeared from the top 20 list of trees produced by Dutch nurseries. New cultivars with increased resistance to DED are used to a limited extent only. Apparently the lasting problems with DED... Mehr ...