Vectors of Dutch Elm Disease in Northern Europe

Potential Dutch elm disease vector beetle species were caught with pheromone bottle traps and handpicked in 2019: in total, seven species and 261 specimens were collected. The most common was <i>Scolytus triarmatus</i>, but by percent, the incidence of <i>Ophiostoma novo-ulmi</i> was highest in <i>Scolytus scolytus</i>, followed by <i>Xyleborinus saxesenii</i> and <i>S. triarmatus</i>. We analysed the beetles<i>'</i> DNA using PacBio sequencing to determine vector beetles of <i>Ophiostoma novo-ulmi</i>. <i>Ophiostoma novo-ulmi</i> was found on six out of seven analysed beetle species: <i>Scolytus scolytus</i>, S<i>. triarmatus</i>, <i>S. multistriatus</i>, <i>S. laevis</i>, <i>Xyleborinus saxesenii</i> and <i>Xyleborus dispar</i>. The last two beetles were detected as vectors for <i>Ophiostoma novo-ulmi</i> for the first time. Previous knowledge on the spread of beetles is discussed.