Feeding by Scolytus bark beetles to test for differently susceptible elm varieties
Dutch elm disease (DED), caused by the fungi Ophiostoma ulmi and O. novo-ulmi, has reduced elm populations severely in Europe and North America. Breeding programmes are in action to find less susceptible elm varieties suitable for re-establishing elm stands. Bark beetles, mainly Scolytus spp., are the only known natural vectors of DED. During twig feeding, beetles transfer Ophiostoma spores to hea